Very interesting video! I have the exact same Hydronic 10 heater installed on my 1999 Catalina 470, and it has never worked since I bought the boat. And I never really needed it as I live where it's warm almost all the time. I'm investigating getting the system going again, mostly to heat water for showers and doing the dishes, and for the rare cold day. You've given me a lot of useful information, thank you!
I am in the process of understanding my central boat heating system based on Eberspächer Hydronic M 10. The yacht is a Garcia 54 and I have two radiators in the saloon and one in each of the three cabins and one in the master toilet. After searching for info, looking at endless videos and reading manuals I found your video that explains the system in a great way, easy to follow and makes my work easier. You just made my day. Awesome, thank you and keep up the great work.👌👍
Really glad it helped you! That was the objective of the video. I was in the exact same situation and had to dig around in manuals, spend endless hours following the pipes in my boat trying to understand my system :)
We have a Hurricane hydronic heating system on our Tollycraft 34. It's set up very similarly to your boat and performs very well. It was 10°F last night and we kept the boat at 50°F to prevent freezing.
floorheating would generally be a good idea i believe as it maximizes the surfaceare of energytransfer. your energy loss rom all windows etc. must outperform the abilities of your fans volume per time unit at a certain temperaturepoint. For safetyreasons i would go for an aditional airheater, so that you have redundancy aswell as means to speed up the process.
Hey Thorsten, great video. Thank you for sharing. I like the concept of keeping the air heating and water heating on the same system. Hadn't thought of that. Hope all is going great with the system a year later. Cheers!
Thank you most kindly. I have opted for warm air. But am considering useing an egr on the exhaust to give me hot water for the shower. Hopefully I'll be able to use natural thermosyphon . You video is very clear and concice . Cheers
Great video, Invaluable information, thanks, I do not have a heat exchanger on my engine so I am in the process of installing hot water heater and cabin heating in the same fashion.
Your video is very informative and interesting. I like the way you choreograph the video and the transition between different camera perspective is very smooth and nicely done.
For stiff radiator hose you can put the ends in near boiling water and they'll slip right on the fitting like butter. Not convient sometimes but it works wonders.
Great video. Jus trying to make a thermo to V run, from BMW but might end u using a thermo to C/V. But thinking of trying to loop into the existing water tank that is heated by the motor. And then onto a radiator or two but that is going to take some planning as there will have to be switches I guess.
Thanks, Thorsten, for your great coverage. I have installed the same heater in my Southerly 135, Only I had to start from scratch installing all of the hoses over many weeks. I am interested in the noise level of your fans. Mine are Eberspacher standard and are excessively noisy, particularly the supposed 4 Kw duct unit in the main saloon. I am looking for a silent solution. The older fan units you have may very well be superior to the newer units made to a budget in France. I live permanently on my boat and shower aboard every day. The fan unit in the head is vital to drying out the head after each shower. I don’t have the auxiliary water pump either, I will get one and add it, but you can achieve the same by adding a really power feed to the heater water pump. I like the idea of the backup function though. For water line modifications I have 4 long nose vise grip pliers to pinch of the hoses as near as possible to any section I am modifying. With these I spill very little. I have my Heater unit up in the roof of my equipment space and have the header tank below the water heater and I charge the system through a valve feed in line at floor level using an electric drill utility pump (Euro 10 at the hardware store). I see that you are in aviation so I offer a little tip. I suggest that some time you talk to the maintenance people and obtain a quantity of aircraft cable for the next time you have your mast off the boat. The reason is that this wire is silver plate, silicone sheaved, over sheaved with fiberglass braid, and over sheaved again with an anti friction cover (possibly Mylar). Ie this is cable of a much higher rating that will last many years more than standard wire, and it is not that expensive relative to the value of the mast, or the cost of taking the mast down to repair failed wiring. I look forward to future videos.
I found this researching a new 45 foot 4 screw freightliner :) IDK if this is why you had no fuse, but in the USA all heating engineered systems must be fail 100% heat, so dampers or pneumatic relay lines for cool / heat will give you full heat in summer. Those rules came from the US north east, but also apply in Arizona!
Awesome video, great explanation. I have an air heater now and I'm thinking installing a water heater instead to get warm tap water. Your video helps me to understand the complexity of the installation.
Great video. Building a sailboat and going to have same basic system. I have a Webasto heater. A couple of questions, if I may? I see you are running the glycol solution through a heat exchanger to warm the engine, so how does the warm engine coolant in the heat exchanger get circulated through the block? Is there another pump involved? Also, is the heater isolated from the accommodations, in it's own locker for example? Thanks for sharing. Always good to compare notes. Take care.
just got done finishing my install of a hydronic heating system. I have watched your video multiple times to get a good understanding. I share your assessment of sluggish performance from the heating of the air. I have copper tube radiators with computer fans. I am wondering if a car style heater matrix would deliver more heat to air transfer. I can't say I feel like replacing my heat exchangers to find out, but I sure am curious. thanks for the video. Cheers from Seattle, WA US
Hi. Great and helpful video. Thank you for that. Im about to re-do the hydronic system in my boat. Is your tapwater tank a combined 220v and heatexchanger type? if you run it only on 220v, and then run the circulation pump in the heating system, will you then get heating onbord? I wonder if this is a way to heat the boat at shorepower.. Best regards Yngve Haugesund
Great video! If you're around Bergen in summer 2021 I might be around for a visit (depending on corona restrictions and border restrictions) with my boat.
Please do! My plan for the summer right now is to sail up as far north as the weather (and my endurance) allows, but I will be in Bergen from time to time. Just give me a heads up when you are on your way.
Thanks for sharing. I plan to add this type of system in a van conversion. Two questions if you don’t mind. 1. Do you and how far ahead have to plan ahead when you want to get hot water for the sink? 2. Are you just using normal mixing valves to mix tank and hot water to get the desired water temperature? I’m wondering if somehow you could have separate thermostats even for the water, like different loops that can be run intermittently to achieve the correct temperature. This is more complex but obviously might be more accurate and even save water and energy I’d think.
To answer your question: 1. In my setup it takes 15-20 minutes to get hot water. Usually we switch on the heater (in case we are not heating the cabin anyways) when we are done preparing lunch/dinner and let it heat during the course of the meal. Then we have hot water when we are done eating to do the dishes. But I assume that depends highly on the size of hot water tank you have. The volume of ours is (I think) 25 liters. 2. Yes, just run-of-the-mill mixing valves. Most likely you can install different loops with different thermostats. But then you need to actuate valves and synchronise that with more thermostats which adds another layer of complexity and all around more stuff that can break potentially. I am not sure if you could save water with that, but it might save some fuel/electricity, though in my setup probably not noticeably. But for much bigger boats that is certainly the case. If you think about adding more control over the output water temperature from the heater: Eberspächer offers control units for its heaters where you can fine-tune that. I would suspect that other manufacturers offer the same. And good luck with your installation!
Great information as I am researching installing hydronic heating in my Island Packet as living in the US I spend 6 months in Alaska even in the winter. The use of the system for domestic water is great. Thank you.
Great detailed video, thanks for that! I have a Webasco hydronic system on my 1883 C&C 43 Landfall. The engine is tied into the water heater together with the Webasco and has 4 valves that can be used to isolate them where they meet at this hot water tank. With the valves open, the engine could pump coolant throughout the entire loop and heat the boat (with just the engine) if I had a way to operate the individual fans in the heaters. Like you, I have a concern with having such a large loop with potential failure points that could lose coolant and put my engine at risk. Right now I feel pretty safe with the ability to only heat the domestic water keeping the valves to the entire heating system closed. Because you have a heat exchanger from the engine to the heating loop, your risk is minimal. I was wondering what heat exchanger you used and if you found much loss through exchanger vs having the large single loop system I presently have. I know these hydronic heaters are used in vehicles (trucks) in the same single loop but have fewer failure points that these much larger systems on a boat.
Great video, just more info into the memory bank, however your delivery of the very tiny jokes. " fans fanning" for instance was actually funny. While I will never have this type of system, the method of figuring out what was needed and not makes the video worth it to me. Thanks
Quality video documentation, thank you for sharing. I have almost no experience with marine heating systems (or heating systems in general), but I found your explanations to be accessible and informative. Can I ask how long the repair took you from start to finish?
Approximately one and a half week. Working 2 hours on it per day. Finding out how all of it works together was the hardest part, there was almost no documentation how everything was connected. So finding out which hose goes where and what it does was the really hard part, crouching around in the underbelly of the boat. Well, and driving back and forth to the hardware store because I forgot the one or the other thing ... I think if it would have been an installation from scratch, you have all the parts and a solid plan it can be done in two days. But with boats there seem to always pop up problems out of nowhere :-)
@@SailingSyvsover Wow, well, I'm still thoroughly impressed with that speed. I'll tell myself for my own self-esteem that you had some prior general knowledge about boat mechanical and electrical systems!
Thanks :-) It wasn't the first time I had to search along the cables, so knowing all the possible cable channels and nooks and crannies definitely helped. Earlier 2020 I upgraded the navigational system (chart plotter/auto pilot/instrumentation etc), so there isn't a panel that I hadn't removed before. The wet system, i.e. hoses etc was completely new to me. But asking around in the marina and at the shop helped a lot. There are no stupid questions :-)
Great video. Might I ask why you plumbed the cabin heaters in series as opposed to parallel? I’d think there would be several advantages to running them in parallel. 1. They would all be the same temperature. 2. You could plumb in shut off valves if you ever had to remove one for service and still have heat at the others.
Well, short answer is that the plumbing was that way in the previous configuration. Long answer is that it’s easier imho. I am not entirely sure how easy it is to realize a proper distribution that really divides the heat equally. I understand that it would be preferable, but on the other hand it introduces a new level of complexity. If you build something like that let me know how it goes!
Thanks for posting the fine video. It is very helpful! I am considering adding a similar system to my camper van to replace the little Propex heater since now the engine has been swapped to a diesel. Looking at your last schematic, it appears that the heroic heater is not warming the engine when it is off. Of am I missing something? I will need to also warm my engine in cold temps prior to starting. I understand that keeping the engine coolant separate from hydronic loop. Maybe an additional coolant pump to warm the engine? Much appreciated!
Thank you for excellent video and the detailed information! I already have most of the components working, except our boat hot-water tank is not heated by Webasto 90 heater, so i would need to add a heat exchanger and an auxiliary pump. I have a couple questions: 1. What heater exchanger unit did you use, could you share a link? 2. When you are motoring, so the engine is running and auxiliary pump is working, the water-tank is heating up …but what if you also want to warmup the boat. Can you control your fans separately and without turning on the heater? Thank you in advance!
Hi! To your questions: 1. I have unfortunately no brand for the heat exchanger. But any water/water plate heat exchanger should do as long as you can fit the connectors somehow. 2. If you take a look at the circulation diagrams (the link is in the description), you can see that the auxiliary pump is pumping the heating medium also past the heater fans in the cabin. So if you switch on the cabin fans (or they switch on thermostat controlled), you can heat up the cabin, too. In my setup they are separately controlled through thermostats, independently from the heater.
That`s a very good vid, love the humour. Have been getting ready for such a system for a while but keep running into exhaust routing problems. Do you know the exhaust temperature at the exit of the unit? If i could find this out i could simulate it with a heat gun and some of the exhaust ducting and figure out the heat loss to the exhaust exit and not cook anything else in between. Thanks, Warren
Sorry for the late reply! Your message didn't show in youtube studio, just see it on the normal page right now. I will measure it for you in the coming days! At the outlet it is hot enough to hurt. But I couldn't tell you right now if it is 50 or 100 degrees C (my hands are not that finely calibrated 🙂)
@@SailingSyvsover Hi, thanks that`d be great. Little laser heat measuring gun is the easiest. Have put the project back a bit while we go sailing but likely a trip away will lead to more enthusiasm. Cold water is an excellent motivator,,,
Can you add a oil pressure switch (NO) on the engine and when the engine starts it will pass the grounding leg to your relay activating it and cut it off when the engine stops. Would this make it automatic and then the remote switch would be left on all the time or off when you need to shut the system off.
Ok I haven't run out of fuel same system iv had for years . But heater has shut it's self down for no reason and wont restart after a few attempts it's got an e 10 code ? Plenty of fuel 12.7v with the glow plug on and 12.9-13.2v on a 390 amp triple leasure battery fuel line is around 4-5 ft long . I've tried priming it just doesn't want to know ?
Hey Thorsten, thank you for your useful info. I have a question, does your schedule also work when the radiators are conected in a paralel way? Thank you for the info. L
In this boat there was an exhaust installed already. I think you can buy the parts from Eberspächer or other manufacturers. It is just a stainless pipe which leads through the hull outside in the aft (well above the waterline). The only thing which you have to make sure is that it has the right diameter so that you can connect it to the exhaust pipe.
Does each air handler in each cabin handle both the heating and cooling for the boat or do you need 1 air handler for heating and 1 seperate air handler for cooling. If the boat already has a reverse chiller system, could a boiler heat system be added using the existing cabin air handlers? Would seperate lines need to be run to each air handler to handle the addition of the new heating / boiler system?
Great video! Can you tell us what controller/timer your system is using? I am putting a very similar system in an caravan but I am not sure what timer/controller to use.
Sorry for the late answer! The controllers for the fans/radiators are unfortunately some no-name product. It is really just a simple temperature control switch controlling the 12V to the fans. The fans are switched on if the temperature goes below the programmed threshold on the display (gives the fan 12V, so that it can blow air through the radiator and into the cabin). It switches off if the temperature is reached. The Hydronic itself does not need a control unit in this setup. It keeps the water-temperature at a constant value (around 70°C) and circulating constantly as long as it is on. Hope that helps.
Great video! I am doing exactly the same project, upgrading the Espar D10 to the latest Espar 10 (M-II). What did you do for the wiring harness? Were you able to use the old harness?
Great video, no sailboat experience for me yet, only gathering information for future yet I was able to get a good working concept of what all is involved with such a system, as well as the positives & drawbacks. One question though, do you have any idea on your diesel consumption while running high/low? The boats I'm looking at don't have huge fuel tanks, so it would be nice to have an idea on endurance. Here on the Northern Gulf of Mexico, it doesn't get anywhere near as cold as you get, so I wouldn't have to run it as much.
Glad that you liked the video! There are 4 power modes for that model. Nominal fuel consumption is as follows: Power 0.9 l/h Large 0.65 l/h Medium 0.4 l/h Small 0.18 l/h It cycles between the latter two in my installation after the initial warm up. You can find more detailed information in the manual here (along with power consumption): www.butlertechnik.com/downloads/Eberspacher_Heater_Hydronic_M-II_Technical_description,_installation_instruction_manual.pdf
Do you mean the electric boiler in the system? I am actually not sure what power the electric element in there has. If you mean the hydronic heater it has a maximum power of 9500W. But that is only if it is really running at its max capacity. It usually runs around at its 1500W power mode. The radiators were already installed in the boat. But you get almost the same radiators from e.g. Eberspächer.
That's a beautiful system. I just rerouted my Espar D5W SC to the hot water tank and am having trouble with bleeding the system. Where in your system did you add the bleeder valve? I also have some concern that the unit does not have the capacity to effectively supply the hot water tank and 3 radiators. Any comments would be appreciated.
I added the bleeder valve where I suspected an air bubble to be forming. For me that is right after the heater. In my installation right after the heater the heating fluid is first pumped down and then later has to go "uphill" again. So I suspected it could create an airlock. Like in a siphon under a sink. But it might be different for you depending on how your system is laid out. If I recall correctly, it is recommended to have the heater at the lowest position in the system to prevent exactly that, but that was not possible for me. I can only recommend you to look for places where it is most likely that air can build, like "hose loops" going first down and then up, then install a bleeding valve at the most convenient location. As for the heating capacity, how big is your boat? And how big is the water tank? Radiators are notoriously slow to heat up any space in comparison to air-heaters. I am working in on an upgrade with an additional defroster unit which I will install as soon as I find the time. I'll make an updated video on it when it is done. I suspect that it increases the speed of which the boat is heated to initial temperature immensely.
@@SailingSyvsover The boat is a 2003 Bavaria 36 and it has a 6 gal hot water tank. Other than the header tank, the heater is at the highest point in the system without any significant hose loops. I may try leaving the cap off the header tank (similar to bleeding a diesel engine coolant system) and then may consider installing a bleed valve. Thanks
Thank for a very interesting video! Couldn't You have used the old tank as a heat exchanger? You could have run glycol through the heater, pump and the tank and thus increasing the volume of (glycol) fluid the heater works with. Then You could run the radiators as it's own circuit (albeit with another pump) through the old tank's spiral. If the heater circuit and the radiator circuits are separated You might be able to run the heater more steadily. Although Your model of heater seems to have a really good range of heating power.
Excellent video. I’ve been trying to find a solution for hot water, but already have a Webasto air system for heating. So I doubt I go this route, but always good for ideas and thought. I wonder if you have an issue with the defrosters (radiators are always slow) - I installed a defroster on the engine cooling system and it is really fast and warm which is a great thing early season as we leave the mooring. I did that about 3 years ago and was very easy. Maybe there is some build up or sediments in your defrosters from that old water tank?
Thanks! The defrosters/fans in the boat are quite small and more or less made to be very silent. They deliver slow and steady heat and you have to get close to hear them. In that respect they are more like radiators with a bit of airflow. The system as it is is designed to be kept on for hours on end without being a noise nuisance. I thought about sediment, too, but the return flow would be a lot less if there would be some serious blockage and they output the heat, just not at the rate I'd hoped for. I did flush the whole system (in both directions) and the return flow was crystal clear. I got a proper 4.1kW defroster unit which I install at some point so that I can switch it on and off independently and will make an update about that. The fan is significantly louder and outputs a lot more air. I am pretty certain that this will alleviate the problem of the initial heating. Once everything has its initial temperature I can switch the defroster off and the normal fans take over to keep the temperature. That is the plan at least :-)
@@SailingSyvsover, sounds like the design is a good one slow and steady. And yes the defroster I have is extremely noisy. Good plan to add such a device on a separate switch, with the motor running the added noise makes no difference. But it is not for long term running when it comes to sanity ;-).
@@milesbuckhurst504 We use the heating mostly after we arrived, especially when sailing. To keep the sheets organised we often throw the ends down the companionway, so much of the heat would dissipate outside anyway. Upon arrival I hope that I can switch on the defroster for 30 minutes or so to get some baseline heat in the salon. Afterwards the fans should have enough power to keep that baseline and heat the fore and aft cabin.
Det er pin B1 (i stikkontakten til styrekabelen) for den gamle hydronic 10 med positiv signal. Det er beskrevet på side 17/18 i manualen, se f.eks. her: www.butlertechnik.com/downloads/Eberspacher_Heater_Hydronic_10_Installation_Manual.pdf
Etter å ha studert koblingsskjema og en telefon til elektro diesel i bergen så kan man laske over 10 til elve på hovedkontakten og vips har man kontinuerlig drift.
And just for clarification because I don't mention it in the video explicitly: It is a 12V system. In the manual it states for the power modes "Medium ~ 39 Watt" and "Small ~ 35 Watt" under power consumption. Which would then be 2.92A and 3.25A (at exactly 12V). So it is very close to that.
Great video, thanks for sharing your experiences. I am currently restoring a. 50year old Nicholson 38 and have been puzzling over how to integrate hydronic diesel heater with engine coolant. Obvious now I see it but the heat exchanger is the way to go. Keeping the two systems separate but connectable if you see what I mean. Any recommendations on a suitable size a spec of an appropriate heat exchanger? Cheers Jon
I am not even sure what the exact specifications of mine are. It was there when I bought the boat :-) So I cannot recommend you any number/spec to look after. But I would definitely go for the biggest you can fit comfortably and which you can afford. The more surface area the better the heat exchange rate.
Jeg bruker ingen timer faktisk. Det var heller ingen fra før. Hydronicen går i "lav" modus eller helt i "sove" modus når vannet i kretsløpet har høy nok temperatur og temperaturen endrer seg ikke vesentlig deretter. Hvis temperaturen går ned så slår han seg på igjen. Siden jeg er alltid om bord når jeg bruker systemet trenger jeg ikke en timer. Håper det hjelper ...
@@SailingSyvsover hvordan starter og stopper du den? Jeg har montert første gen m10, med den fulgte en timer, men den går max to timer. Ønsker å få den til å gå uendelig.
@@gacco11 I manualen "HYDRONIC M-II Technical description, installation, operation and maintenance instructions" finns det på side 30 en beskrivelse av de enkelte kontaktene i kontrolkabelen/pluggen På den eldre modellen er det kontakt A1, på den nye C4 med funksjonen "Heater on" (gul kabel). Jeg antar at i din installasjon er det timeren som gir 12V til kontakten. I min installasjon gir jeg 12V direkte (gjennom en bryter i kontrollpanel) på den. Så lenge bryteren står på går hydronicen. Du kan jo prøve å måle med en multimeter om det er den som styrer hydronicen. Hvis det er den så kan du antageligvis går "forbi" timeren. Men for å si mer måtte jeg nesten se installasjonen din ... Håper det hjelper!
@@gacco11 Ja, slik er det i min setup. Men som sagt: jeg ville måle det med multimeter for sikkerhets skyld før du setter inn en bryter. Mål om det er +12V på den gule kabelen når timeren slår på varmeren og om spenningen er tilbake til 0V når varmeren slår seg av. Og hvis det er tilfelle så kan du prøve å sette inn en bryter i stedet for timeren.
Good thing my boat it's just 9.5meter long with just one room for a bed room . Heating ? Well I have 3 options on the boat . Option 1 Electric heater 1000watt. Option 2 Diesel heater to air . Option 3 Just burning wood . So i have all 3 on board . For hot water ? Don't need id we have on the port a shower / toilet and the wasmachine with coins. For cleaning dishes a waterkoker will de the job. And we have here water boiler . It's works on 12/24 and 220volt. You have than 6 to 10 liter of 80c of hot water.
I am fitting a diesel water heater to a home hot water service, simply because natural gas is a horrible rip off now. When I worked out the cost per 1 kw/hr of energy, it was AUD $20. This is all in a country that is third largest exporter of natural gas in the world. LoL, no fuse/breaker between old heater and battery.........omg, fires on a boat are very undesirable.
As far as I know at 60 °C Legionellae die within 32 minutes. That temperature is reached easily in the water tank. Other than that regular disinfection of the whole fresh water system with chlorine like I do anyways every season. Never heard that that is an issue (at least here in Norway).
@@SailingSyvsover I know little... but when I have researched similar radient heating for camper/boat/house there is a lot of info out there about not mixing water supply with heating system... or legionnaires' disease can occur.
@@gr8jpn Maybe they mean that you should not use the heating medium itself. I am not sure honestly. And even Eberspächer itself advertises on their homepage with the sentence "Heats the domestic water in addition to the passenger compartment" ...
@@gr8jpnIt's a 'closed loop' or 'Indirect' system. The heating fluid (In this case, an antifreeze type mix) circulates through a copper coil which runs through the hot water tank, acting like a heat exchanger, and heats the water indirectly so there is no cross-over or contamination of the domestic hot water, which is fed from the boats fresh water supply. Hope this helps :)).
Very interesting video! I have the exact same Hydronic 10 heater installed on my 1999 Catalina 470, and it has never worked since I bought the boat. And I never really needed it as I live where it's warm almost all the time. I'm investigating getting the system going again, mostly to heat water for showers and doing the dishes, and for the rare cold day. You've given me a lot of useful information, thank you!
I am in the process of understanding my central boat heating system based on Eberspächer Hydronic M 10. The yacht is a Garcia 54 and I have two radiators in the saloon and one in each of the three cabins and one in the master toilet. After searching for info, looking at endless videos and reading manuals I found your video that explains the system in a great way, easy to follow and makes my work easier. You just made my day. Awesome, thank you and keep up the great work.👌👍
Really glad it helped you! That was the objective of the video. I was in the exact same situation and had to dig around in manuals, spend endless hours following the pipes in my boat trying to understand my system :)
We have a Hurricane hydronic heating system on our Tollycraft 34. It's set up very similarly to your boat and performs very well. It was 10°F last night and we kept the boat at 50°F to prevent freezing.
floorheating would generally be a good idea i believe as it maximizes the surfaceare of energytransfer. your energy loss rom all windows etc. must outperform the abilities of your fans volume per time unit at a certain temperaturepoint. For safetyreasons i would go for an aditional airheater, so that you have redundancy aswell as means to speed up the process.
Hey Thorsten, great video. Thank you for sharing. I like the concept of keeping the air heating and water heating on the same system. Hadn't thought of that. Hope all is going great with the system a year later. Cheers!
Thank you most kindly.
I have opted for warm air. But am considering useing an egr on the exhaust to give me hot water for the shower. Hopefully I'll be able to use natural thermosyphon . You video is very clear and concice .
Cheers
This video is so helpful. I'm looking to install a new hydronic system on my 44' sailboat, and this really helps my planning.
Glad it was helpful, and good luck with the installation!
Thank you for sharing and working through the pro's and cons. Very informative!
My pleasure!
Great video, Invaluable information, thanks, I do not have a heat exchanger on my engine so I am in the process of installing hot water heater and cabin heating in the same fashion.
Your video is very informative and interesting. I like the way you choreograph the video and the transition between different camera perspective is very smooth and nicely done.
Glad you liked it!
Great job on the installation and the explanation of how it works
For stiff radiator hose you can put the ends in near boiling water and they'll slip right on the fitting like butter. Not convient sometimes but it works wonders.
Great video. Jus trying to make a thermo to V run, from BMW but might end u using a thermo to C/V. But thinking of trying to loop into the existing water tank that is heated by the motor. And then onto a radiator or two but that is going to take some planning as there will have to be switches I guess.
Thank you for sharing this video, really awesome for its clarity, especially for a non-pro as I am. I'm looking for the
Glad it was helpful!
Excellent video. I am in the planning stages of boat purchase in the Spring. Will be a full-time live-aboard, cold climate as well as warm climate.
Glad it was helpful!
Thanks, Thorsten, for your great coverage. I have installed the same heater in my Southerly 135, Only I had to start from scratch installing all of the hoses over many weeks. I am interested in the noise level of your fans. Mine are Eberspacher standard and are excessively noisy, particularly the supposed 4 Kw duct unit in the main saloon. I am looking for a silent solution. The older fan units you have may very well be superior to the newer units made to a budget in France. I live permanently on my boat and shower aboard every day. The fan unit in the head is vital to drying out the head after each shower. I don’t have the auxiliary water pump either, I will get one and add it, but you can achieve the same by adding a really power feed to the heater water pump. I like the idea of the backup function though. For water line modifications I have 4 long nose vise grip pliers to pinch of the hoses as near as possible to any section I am modifying. With these I spill very little. I have my Heater unit up in the roof of my equipment space and have the header tank below the water heater and I charge the system through a valve feed in line at floor level using an electric drill utility pump (Euro 10 at the hardware store). I see that you are in aviation so I offer a little tip. I suggest that some time you talk to the maintenance people and obtain a quantity of aircraft cable for the next time you have your mast off the boat. The reason is that this wire is silver plate, silicone sheaved, over sheaved with fiberglass braid, and over sheaved again with an anti friction cover (possibly Mylar). Ie this is cable of a much higher rating that will last many years more than standard wire, and it is not that expensive relative to the value of the mast, or the cost of taking the mast down to repair failed wiring. I look forward to future videos.
Great video! Thanks a lot. I plan to install a similar system in my Volvo C304
Great video, and your humor adds to the understanding. One question if I may. What water tank and ssize are you using?
I found this researching a new 45 foot 4 screw freightliner :) IDK if this is why you had no fuse, but in the USA all heating engineered systems must be fail 100% heat, so dampers or pneumatic relay lines for cool / heat will give you full heat in summer. Those rules came from the US north east, but also apply in Arizona!
Awesome video, great explanation. I have an air heater now and I'm thinking installing a water heater instead to get warm tap water. Your video helps me to understand the complexity of the installation.
Thank you!
Great video. Building a sailboat and going to have same basic system. I have a Webasto heater. A couple of questions, if I may? I see you are running the glycol solution through a heat exchanger to warm the engine, so how does the warm engine coolant in the heat exchanger get circulated through the block? Is there another pump involved? Also, is the heater isolated from the accommodations, in it's own locker for example? Thanks for sharing. Always good to compare notes. Take care.
just got done finishing my install of a hydronic heating system. I have watched your video multiple times to get a good understanding. I share your assessment of sluggish performance from the heating of the air. I have copper tube radiators with computer fans. I am wondering if a car style heater matrix would deliver more heat to air transfer. I can't say I feel like replacing my heat exchangers to find out, but I sure am curious. thanks for the video. Cheers from Seattle, WA US
Excellent video. Thank you!
Hi. Great and helpful video. Thank you for that. Im about to re-do the hydronic system in my boat.
Is your tapwater tank a combined 220v and heatexchanger type? if you run it only on 220v, and then run the circulation pump in the heating system, will you then get heating onbord?
I wonder if this is a way to heat the boat at shorepower..
Best regards Yngve
Haugesund
Great video! If you're around Bergen in summer 2021 I might be around for a visit (depending on corona restrictions and border restrictions) with my boat.
Please do! My plan for the summer right now is to sail up as far north as the weather (and my endurance) allows, but I will be in Bergen from time to time. Just give me a heads up when you are on your way.
Thanks for sharing. I plan to add this type of system in a van conversion. Two questions if you don’t mind.
1. Do you and how far ahead have to plan ahead when you want to get hot water for the sink?
2. Are you just using normal mixing valves to mix tank and hot water to get the desired water temperature?
I’m wondering if somehow you could have separate thermostats even for the water, like different loops that can be run intermittently to achieve the correct temperature. This is more complex but obviously might be more accurate and even save water and energy I’d think.
To answer your question:
1. In my setup it takes 15-20 minutes to get hot water. Usually we switch on the heater (in case we are not heating the cabin anyways) when we are done preparing lunch/dinner and let it heat during the course of the meal. Then we have hot water when we are done eating to do the dishes. But I assume that depends highly on the size of hot water tank you have. The volume of ours is (I think) 25 liters.
2. Yes, just run-of-the-mill mixing valves.
Most likely you can install different loops with different thermostats. But then you need to actuate valves and synchronise that with more thermostats which adds another layer of complexity and all around more stuff that can break potentially. I am not sure if you could save water with that, but it might save some fuel/electricity, though in my setup probably not noticeably. But for much bigger boats that is certainly the case.
If you think about adding more control over the output water temperature from the heater: Eberspächer offers control units for its heaters where you can fine-tune that. I would suspect that other manufacturers offer the same.
And good luck with your installation!
Great information as I am researching installing hydronic heating in my Island Packet as living in the US I spend 6 months in Alaska even in the winter. The use of the system for domestic water is great. Thank you.
Great detailed video, thanks for that! I have a Webasco hydronic system on my 1883 C&C 43 Landfall. The engine is tied into the water heater together with the Webasco and has 4 valves that can be used to isolate them where they meet at this hot water tank. With the valves open, the engine could pump coolant throughout the entire loop and heat the boat (with just the engine) if I had a way to operate the individual fans in the heaters. Like you, I have a concern with having such a large loop with potential failure points that could lose coolant and put my engine at risk. Right now I feel pretty safe with the ability to only heat the domestic water keeping the valves to the entire heating system closed. Because you have a heat exchanger from the engine to the heating loop, your risk is minimal. I was wondering what heat exchanger you used and if you found much loss through exchanger vs having the large single loop system I presently have. I know these hydronic heaters are used in vehicles (trucks) in the same single loop but have fewer failure points that these much larger systems on a boat.
Great video, just more info into the memory bank, however your delivery of the very tiny jokes. " fans fanning" for instance was actually funny. While I will never have this type of system, the method of figuring out what was needed and not makes the video worth it to me. Thanks
Great video and guide.... is condensation a problem for you and if so how do you mitigate that?
Hey man,
Nice video l look all the way to the end really interesting👍
Ever tried warm beer?
Dark beer between 34-38°C is quite a pleasure on a cold day 🙂
Skål og alt vel ⛵☃️🍻
Quality video documentation, thank you for sharing. I have almost no experience with marine heating systems (or heating systems in general), but I found your explanations to be accessible and informative. Can I ask how long the repair took you from start to finish?
Approximately one and a half week. Working 2 hours on it per day. Finding out how all of it works together was the hardest part, there was almost no documentation how everything was connected. So finding out which hose goes where and what it does was the really hard part, crouching around in the underbelly of the boat. Well, and driving back and forth to the hardware store because I forgot the one or the other thing ... I think if it would have been an installation from scratch, you have all the parts and a solid plan it can be done in two days. But with boats there seem to always pop up problems out of nowhere :-)
@@SailingSyvsover Wow, well, I'm still thoroughly impressed with that speed. I'll tell myself for my own self-esteem that you had some prior general knowledge about boat mechanical and electrical systems!
Thanks :-) It wasn't the first time I had to search along the cables, so knowing all the possible cable channels and nooks and crannies definitely helped. Earlier 2020 I upgraded the navigational system (chart plotter/auto pilot/instrumentation etc), so there isn't a panel that I hadn't removed before. The wet system, i.e. hoses etc was completely new to me. But asking around in the marina and at the shop helped a lot. There are no stupid questions :-)
Great video. Might I ask why you plumbed the cabin heaters in series as opposed to parallel? I’d think there would be several advantages to running them in parallel. 1. They would all be the same temperature. 2. You could plumb in shut off valves if you ever had to remove one for service and still have heat at the others.
Well, short answer is that the plumbing was that way in the previous configuration. Long answer is that it’s easier imho. I am not entirely sure how easy it is to realize a proper distribution that really divides the heat equally. I understand that it would be preferable, but on the other hand it introduces a new level of complexity.
If you build something like that let me know how it goes!
Thanks for posting the fine video. It is very helpful! I am considering adding a similar system to my camper van to replace the little Propex heater since now the engine has been swapped to a diesel. Looking at your last schematic, it appears that the heroic heater is not warming the engine when it is off. Of am I missing something? I will need to also warm my engine in cold temps prior to starting. I understand that keeping the engine coolant separate from hydronic loop. Maybe an additional coolant pump to warm the engine? Much appreciated!
Super Intro!
Good video sprinkled with the right amount of sarcasm.
Very helpful and informative many thanks
Thanks for the informative video . Great stuff. Best regards from Jarle
Ingen årsak! Hvis du er i Bergensområdet kom og si hei :-)
Thank you for excellent video and the detailed information! I already have most of the components working, except our boat hot-water tank is not heated by Webasto 90 heater, so i would need to add a heat exchanger and an auxiliary pump. I have a couple questions: 1. What heater exchanger unit did you use, could you share a link? 2. When you are motoring, so the engine is running and auxiliary pump is working, the water-tank is heating up …but what if you also want to warmup the boat. Can you control your fans separately and without turning on the heater? Thank you in advance!
Hi!
To your questions:
1. I have unfortunately no brand for the heat exchanger. But any water/water plate heat exchanger should do as long as you can fit the connectors somehow.
2. If you take a look at the circulation diagrams (the link is in the description), you can see that the auxiliary pump is pumping the heating medium also past the heater fans in the cabin. So if you switch on the cabin fans (or they switch on thermostat controlled), you can heat up the cabin, too. In my setup they are separately controlled through thermostats, independently from the heater.
@@SailingSyvsover Makes sense. Thank you.
That`s a very good vid, love the humour. Have been getting ready for such a system for a while but keep running into exhaust routing problems. Do you know the exhaust temperature at the exit of the unit? If i could find this out i could simulate it with a heat gun and some of the exhaust ducting and figure out the heat loss to the exhaust exit and not cook anything else in between. Thanks, Warren
Sorry for the late reply! Your message didn't show in youtube studio, just see it on the normal page right now. I will measure it for you in the coming days! At the outlet it is hot enough to hurt. But I couldn't tell you right now if it is 50 or 100 degrees C (my hands are not that finely calibrated 🙂)
@@SailingSyvsover Hi, thanks that`d be great. Little laser heat measuring gun is the easiest. Have put the project back a bit while we go sailing but likely a trip away will lead to more enthusiasm. Cold water is an excellent motivator,,,
Excellent video. thanks for sharing.
Nicely done... very nicely done.
Thank you!
Great Video and well helpfull stay safe thanks from the uk 👍👍
Thanks, you too!
Can you add a oil pressure switch (NO) on the engine and when the engine starts it will pass the grounding leg to your relay activating it and cut it off when the engine stops.
Would this make it automatic and then the remote switch would be left on all the time or off when you need to shut the system off.
Ok I haven't run out of fuel same system iv had for years .
But heater has shut it's self down for no reason and wont restart after a few attempts it's got an e 10 code ?
Plenty of fuel 12.7v with the glow plug on and 12.9-13.2v on a 390 amp triple leasure battery fuel line is around 4-5 ft long .
I've tried priming it just doesn't want to know ?
Fantastic video - thank you
thank you the was amazing and very helpful~
thanks for that it was very informative also thanks for the diagram
You're welcome
Hey Thorsten, thank you for your useful info. I have a question, does your schedule also work when the radiators are conected in a paralel way? Thank you for the info. L
How would you calculate the correct size of heater for boat size?
Great video. Very informative.
Glad it was helpful!
Nice video - very well explained
Glad you liked it
Great explaining !
Thanks for the effort! Great video!
My pleasure!
Very helpful, thanks for sharing. How do you vent the hot exhaust, out through a thru-hull or to a chimney on the deck?
In this boat there was an exhaust installed already. I think you can buy the parts from Eberspächer or other manufacturers. It is just a stainless pipe which leads through the hull outside in the aft (well above the waterline). The only thing which you have to make sure is that it has the right diameter so that you can connect it to the exhaust pipe.
Does each air handler in each cabin handle both the heating and cooling for the boat or do you need 1 air handler for heating and 1 seperate air handler for cooling. If the boat already has a reverse chiller system, could a boiler heat system be added using the existing cabin air handlers? Would seperate lines need to be run to each air handler to handle the addition of the new heating / boiler system?
Great video! Can you tell us what controller/timer your system is using? I am putting a very similar system in an caravan but I am not sure what timer/controller to use.
Sorry for the late answer! The controllers for the fans/radiators are unfortunately some no-name product. It is really just a simple temperature control switch controlling the 12V to the fans. The fans are switched on if the temperature goes below the programmed threshold on the display (gives the fan 12V, so that it can blow air through the radiator and into the cabin). It switches off if the temperature is reached. The Hydronic itself does not need a control unit in this setup. It keeps the water-temperature at a constant value (around 70°C) and circulating constantly as long as it is on. Hope that helps.
Great video! I am doing exactly the same project, upgrading the Espar D10 to the latest Espar 10 (M-II). What did you do for the wiring harness? Were you able to use the old harness?
There were some changes logically, that is the reason why I had to add the relay. But as far as I remember was the harness itself the same.
Great video, no sailboat experience for me yet, only gathering information for future yet I was able to get a good working concept of what all is involved with such a system, as well as the positives & drawbacks. One question though, do you have any idea on your diesel consumption while running high/low? The boats I'm looking at don't have huge fuel tanks, so it would be nice to have an idea on endurance. Here on the Northern Gulf of Mexico, it doesn't get anywhere near as cold as you get, so I wouldn't have to run it as much.
Glad that you liked the video!
There are 4 power modes for that model. Nominal fuel consumption is as follows:
Power 0.9 l/h
Large 0.65 l/h
Medium 0.4 l/h
Small 0.18 l/h
It cycles between the latter two in my installation after the initial warm up.
You can find more detailed information in the manual here (along with power consumption): www.butlertechnik.com/downloads/Eberspacher_Heater_Hydronic_M-II_Technical_description,_installation_instruction_manual.pdf
@@SailingSyvsover thanks. Looking forward to looking at more of your videos soon.
Excellent video...
Great video thank you for the information
Glad it was helpful!
thank you fo rthe great video. What is the brand/model of your balance tank? Please
Do you mean the expansion tank? Should be an "Alde Wall Mounted Expansion Tank" 1.5L with 22mm port. Looks identical anyways.
Just use a hairdryer to heat up the hose, makes it so much easier!
Very helpful video, thank you so much! What power is that boiler? And where did you get your radiators from?
Pete
Do you mean the electric boiler in the system? I am actually not sure what power the electric element in there has. If you mean the hydronic heater it has a maximum power of 9500W. But that is only if it is really running at its max capacity. It usually runs around at its 1500W power mode.
The radiators were already installed in the boat. But you get almost the same radiators from e.g. Eberspächer.
That's a beautiful system. I just rerouted my Espar D5W SC to the hot water tank and am having trouble with bleeding the system. Where in your system did you add the bleeder valve? I also have some concern that the unit does not have the capacity to effectively supply the hot water tank and 3 radiators. Any comments would be appreciated.
I added the bleeder valve where I suspected an air bubble to be forming. For me that is right after the heater. In my installation right after the heater the heating fluid is first pumped down and then later has to go "uphill" again. So I suspected it could create an airlock. Like in a siphon under a sink. But it might be different for you depending on how your system is laid out. If I recall correctly, it is recommended to have the heater at the lowest position in the system to prevent exactly that, but that was not possible for me. I can only recommend you to look for places where it is most likely that air can build, like "hose loops" going first down and then up, then install a bleeding valve at the most convenient location.
As for the heating capacity, how big is your boat? And how big is the water tank? Radiators are notoriously slow to heat up any space in comparison to air-heaters. I am working in on an upgrade with an additional defroster unit which I will install as soon as I find the time. I'll make an updated video on it when it is done. I suspect that it increases the speed of which the boat is heated to initial temperature immensely.
@@SailingSyvsover The boat is a 2003 Bavaria 36 and it has a 6 gal hot water tank. Other than the header tank, the heater is at the highest point in the system without any significant hose loops. I may try leaving the cap off the header tank (similar to bleeding a diesel engine coolant system) and then may consider installing a bleed valve. Thanks
Thank for a very interesting video! Couldn't You have used the old tank as a heat exchanger? You could have run glycol through the heater, pump and the tank and thus increasing the volume of (glycol) fluid the heater works with. Then You could run the radiators as it's own circuit (albeit with another pump) through the old tank's spiral. If the heater circuit and the radiator circuits are separated You might be able to run the heater more steadily. Although Your model of heater seems to have a really good range of heating power.
The problem with the old tank was that it was full of rust and the loops not water-tight anymore ... Otherwise I might have used it somewhere else :-)
@@SailingSyvsover thanks. Makes sense
thank you good info
Excellent video. I’ve been trying to find a solution for hot water, but already have a Webasto air system for heating. So I doubt I go this route, but always good for ideas and thought. I wonder if you have an issue with the defrosters (radiators are always slow) - I installed a defroster on the engine cooling system and it is really fast and warm which is a great thing early season as we leave the mooring. I did that about 3 years ago and was very easy. Maybe there is some build up or sediments in your defrosters from that old water tank?
Thanks! The defrosters/fans in the boat are quite small and more or less made to be very silent. They deliver slow and steady heat and you have to get close to hear them. In that respect they are more like radiators with a bit of airflow. The system as it is is designed to be kept on for hours on end without being a noise nuisance. I thought about sediment, too, but the return flow would be a lot less if there would be some serious blockage and they output the heat, just not at the rate I'd hoped for. I did flush the whole system (in both directions) and the return flow was crystal clear.
I got a proper 4.1kW defroster unit which I install at some point so that I can switch it on and off independently and will make an update about that. The fan is significantly louder and outputs a lot more air. I am pretty certain that this will alleviate the problem of the initial heating. Once everything has its initial temperature I can switch the defroster off and the normal fans take over to keep the temperature. That is the plan at least :-)
@@SailingSyvsover, sounds like the design is a good one slow and steady. And yes the defroster I have is extremely noisy. Good plan to add such a device on a separate switch, with the motor running the added noise makes no difference. But it is not for long term running when it comes to sanity ;-).
@@milesbuckhurst504 We use the heating mostly after we arrived, especially when sailing. To keep the sheets organised we often throw the ends down the companionway, so much of the heat would dissipate outside anyway. Upon arrival I hope that I can switch on the defroster for 30 minutes or so to get some baseline heat in the salon. Afterwards the fans should have enough power to keep that baseline and heat the fore and aft cabin.
Great video!
Thanks!
Nice video!
Thanks!
Can you service the water pump within the Eberspacher without having to disassemble the whole of the Eberspacher I.e. do it in situ
Looks like it. It is outside of the casing and is electrically connected with a little plug. Mechanically it is held in place by a hose clamp.
Good video
So you no longer need a hot water tank?
Great Video, Thank You! :))
Glad you liked it!
New viewer. Loved ur vid.
Thanks!
Mener du sa den gamle hydronic 10 har mulighet for å kun kjøre vannpumpen, hvordan?
Det er pin B1 (i stikkontakten til styrekabelen) for den gamle hydronic 10 med positiv signal. Det er beskrevet på side 17/18 i manualen, se f.eks. her: www.butlertechnik.com/downloads/Eberspacher_Heater_Hydronic_10_Installation_Manual.pdf
Etter å ha studert koblingsskjema og en telefon til elektro diesel i bergen så kan man laske over 10 til elve på hovedkontakten og vips har man kontinuerlig drift.
So, the average current draw after the system stabilized was around 4 amps?
Between 3 and 4 amps, that is correct.
And just for clarification because I don't mention it in the video explicitly: It is a 12V system. In the manual it states for the power modes "Medium ~ 39 Watt" and "Small ~ 35 Watt" under power consumption. Which would then be 2.92A and 3.25A (at exactly 12V). So it is very close to that.
to get those hoses on, dip them in boiling water for 30 seconds , then they will push on easy.
Thanks for the tip!
Great video, thanks for sharing your experiences. I am currently restoring a. 50year old Nicholson 38 and have been puzzling over how to integrate hydronic diesel heater with engine coolant. Obvious now I see it but the heat exchanger is the way to go. Keeping the two systems separate but connectable if you see what I mean. Any recommendations on a suitable size a spec of an appropriate heat exchanger? Cheers Jon
I am not even sure what the exact specifications of mine are. It was there when I bought the boat :-) So I cannot recommend you any number/spec to look after. But I would definitely go for the biggest you can fit comfortably and which you can afford. The more surface area the better the heat exchange rate.
Would appreciate a section in all of your tech videos; "this is how you explain the cost to your partner".
Quote from the internet: “My greatest fear is that after I die, my partner will sell my gear for the price I told her it cost when I bought it.”
Hvilken timer bruker du? Satt på en eber timer, den gå max to timer så stanser den. Hvordan har du koblet den?
Jeg bruker ingen timer faktisk. Det var heller ingen fra før. Hydronicen går i "lav" modus eller helt i "sove" modus når vannet i kretsløpet har høy nok temperatur og temperaturen endrer seg ikke vesentlig deretter. Hvis temperaturen går ned så slår han seg på igjen. Siden jeg er alltid om bord når jeg bruker systemet trenger jeg ikke en timer. Håper det hjelper ...
@@SailingSyvsover hvordan starter og stopper du den? Jeg har montert første gen m10, med den fulgte en timer, men den går max to timer. Ønsker å få den til å gå uendelig.
@@gacco11 I manualen "HYDRONIC M-II
Technical description, installation,
operation and maintenance instructions" finns det på side 30 en beskrivelse av de enkelte kontaktene i kontrolkabelen/pluggen På den eldre modellen er det kontakt A1, på den nye C4 med funksjonen "Heater on" (gul kabel). Jeg antar at i din installasjon er det timeren som gir 12V til kontakten. I min installasjon gir jeg 12V direkte (gjennom en bryter i kontrollpanel) på den. Så lenge bryteren står på går hydronicen. Du kan jo prøve å måle med en multimeter om det er den som styrer hydronicen. Hvis det er den så kan du antageligvis går "forbi" timeren. Men for å si mer måtte jeg nesten se installasjonen din ... Håper det hjelper!
@@SailingSyvsover slik jeg forstår det du skriver så skal gul kabel ha pluss når varmeren skal gå. Det kan løses med en enkel bryter?
@@gacco11 Ja, slik er det i min setup. Men som sagt: jeg ville måle det med multimeter for sikkerhets skyld før du setter inn en bryter. Mål om det er +12V på den gule kabelen når timeren slår på varmeren og om spenningen er tilbake til 0V når varmeren slår seg av. Og hvis det er tilfelle så kan du prøve å sette inn en bryter i stedet for timeren.
Good thing my boat it's just 9.5meter long with just one room for a bed room .
Heating ?
Well I have 3 options on the boat .
Option 1
Electric heater 1000watt.
Option 2
Diesel heater to air .
Option 3
Just burning wood .
So i have all 3 on board .
For hot water ?
Don't need id we have on the port a shower / toilet and the wasmachine with coins.
For cleaning dishes a waterkoker will de the job.
And we have here water boiler .
It's works on 12/24 and 220volt.
You have than 6 to 10 liter of 80c of hot water.
I am fitting a diesel water heater to a home hot water service, simply because natural gas is a horrible rip off now. When I worked out the cost per 1 kw/hr of energy, it was AUD $20. This is all in a country that is third largest exporter of natural gas in the world. LoL, no fuse/breaker between old heater and battery.........omg, fires on a boat are very undesirable.
What did you do to ensure you won't get legionnaires' disease from using water tank for heating?
As far as I know at 60 °C Legionellae die within 32 minutes. That temperature is reached easily in the water tank. Other than that regular disinfection of the whole fresh water system with chlorine like I do anyways every season. Never heard that that is an issue (at least here in Norway).
@@SailingSyvsover I know little... but when I have researched similar radient heating for camper/boat/house there is a lot of info out there about not mixing water supply with heating system... or legionnaires' disease can occur.
@@gr8jpn Maybe they mean that you should not use the heating medium itself. I am not sure honestly. And even Eberspächer itself advertises on their homepage with the sentence "Heats the domestic water in addition to the passenger compartment" ...
@@gr8jpnIt's a 'closed loop' or 'Indirect' system. The heating fluid (In this case, an antifreeze type mix) circulates through a copper coil which runs through the hot water tank, acting like a heat exchanger, and heats the water indirectly so there is no cross-over or contamination of the domestic hot water, which is fed from the boats fresh water supply. Hope this helps :)).
that is hilarious. I know exactly what you mean. it is always a mess.