How To Flush Descale Tankless Water Heater and Maintenance heat exchanger Navien NCB240 Combi Boiler
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- Опубліковано 15 лис 2017
- How to Flushing and descaling the heat exchangers on a Navien Combination boiler with vinegar. Clean condensate trap, clean water inlet filter, clean space heat strainer filter. Maintenance. This can prevent the 3 way valve from going bad. Another step I didn't do is to open the 3 way valve when flushing the space heat side to make sure the space heat and domestic plate exchangers get flushed.
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I've seen a tutorial for a water heater but I have a combi-boiler and wanted to make sure I knew what I was doing. This was an excellent video to show me that I was on the right track. Thank you
Really helpful, practical and comprehensive. Thank you.
Thanks. I've been trying to get someone to service my two Navien Combi's for over 18 months now.
I just bought a pump and 3 gallons of vinegar, and with your excellent tutorial, I'll be doing this myself from now on. Thanks for posting this, Well Done!
Solid instructions easy to follow no fluff, my favorite type of vids
Thank you for taking the time and making this video
great video - thanks, now I have a Sunday project
Thank you for this comprehensive video. I have the exact same system installed in 2016. So 2 years later I’m doing my first flush hopefully everything goes ok. Thanks for your help.
The two way valve is notorious for failing on these, so a flush is a good idea!
Two way or the three way valve?
How would you know your 3 way valve is bad?
@@tomfisher5329 It's a 3-way valve and he's right.... they're known to go bad. Navien has actually discontinued the original valve and put a new "revised" version into production for replacement when needed. The crappy thing is they won't be sending these "revised" valves out until the old stock has been depleted. I know this post is 4 years old but thought this might help someone who is flushing their combi-boiler. My 3 way valve went bad the first time and didn't flash a code... just the red-wrench symbol. It has gone again and I once again have the red-wrench symbol flashing (4 years later). My plumber just said to keep running it. After 4 years, I am just doing my first full flush/descale on my unit and so far the domestic side is clean like this video. I hope the other side isn't as grungy as his. Lol. I had a 110 code flashing initially and once I cleaned the air intake screen and the distillate cap.... then reset the system.... the code went away. These are actually very user-friendly to service yourself and the parts are also cheap! Also, the tools you need to do this yourself should cost you about $110.00 Canadian (small sump pump and a washing machine hose kit). Saves me calling a plumber and paying him $400 every year!
Thank you for the video! I have the Same Navien and it was very helpful.
Great to hear! Thanks
Thanks 4 the video. Came across one of these that needs to be descaled badly. Has hot water then goes warm then cold. They have hard water. I told them to also think about an in-line replaceable filter on the cold intake side to prevent this in the future
Good idea. Navien really emphasis water testing and quality for the space heating side, and good to filter domestic water too.
We just descaled the entire unit. Both hot and boiler side. Lots of scale from the hot water and black sediment from the boiler side. Let them both cycle for another an hour. Did the water final flush on the boiler side twice and both filters before and after I think that it’s gonna need service Hot water for a bit then back to Luke warm then cool. Burners are firing in unit But the boiler pipes get hot. Circuit board smells a bit But at least I did the cleaning. So it narrows the problem. It was making a clicking sound from the unit a week before it stopped performing
Very helpfully video, thank you
Thank so much for your nice details video
Thank you for the great video
Every year, my boiler is 15 year's overdue no wonder it started banging and shut down lol!
Thank you for the helpful video!
Only every year on the water heater side. Boiler side less frequent.
Great instructional video, thanks.
Is it possible for you to make a follow up video on how to add boiler conditioner?
I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system. One quarter of the boiler conditioner/flush. Or you could pump it in with a pump.
Excellent video. Subscribed and Thumbs up for your great hard work.
Thank you for the video I have a Navien my house has well water it was installed 4 years ago never was told it needed yearly maintenance to flush I have drained, cleaned and replaced filters but never flushed video is really helpful.
Lori DiNobile2 thanks, glad to hear! the heat side doesnt need to be flushed every year. Just water heater side
It especially should be flushed every year on well water.
A lot of guys say not to flush/descale the boiler side of the Combi units. They say to only do the domestic side. I'm confused? Looks to me as though the boiler side is the filthy mess that should get the most attention.
It's debatable if its necessary..Navien did say they recommend it. But I'd only do it every 5 years or so.
Good video.
Thank you for your video.. so I have some questions.. the first part of the flush is for the heat exchanger as well? there is 2 parts to it, I was trying to do the first part (hoses on the right) and my pump was not pumping the vinegar up, I found out that it was because of the pressure from the boiler, so my 1st question: how do I release pressure from the boiler so that my pump can start circulating.. then I started doing the second part (heat exchanger with a german accent haha) and that worked okay, .. 2nd question: Just doing the heat exchanger (2nd part) alone will be enough?
Thank you for your video and help.
very informative video indeed. so, how do you go about pressurizing the system up to say 12-15psi after? thanks.
After flushing water through the system with city water, you just leave that water in, and let the city water increase the pressure of the heat loop. This system has a city water supply automatic feeder which pulls in water if the pressure drops. If there is no automatic feeder, just hook up a hose from city water to boiler side spigot and slowly introduce water to increase pressure
I was told on the high efficiency condensate LP heaters we need to flush the outside of the heat exchangers too, is this correct? otherwise they rot out I was told, since I lost 1 unit already... I was going to buy a flush kit for the inside, what do we do for the outside of the xchanger where exposed to the heat?
I have a 250/150 navien combo.I cleaned out the condensate filter.The condensate fill tube is located against the back wall.How do you fill it since the rubber stopper is against the back wall of the unit?Thanks for your help.Randy
Very helpful video. Where and/or how do you apply the boiler flush and how much?
I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system. One quarter of the boiler conditioner/flush. Or you could pump it in with a pump.
Thank you for the video. Do I need to isolate the space heater side as well, while I am flushing the water heater side ?
Hi, thanks. No you don't, they are separate.
Mr Larson - Your video on how to descale the Naview is just GREAT. Even a banker like me could do it. My service guy just replaced the 3 way valve. Do you have information on that step. Or next time please do a video on it. Does anybody have info on this step that might be reading this?
Great, thank you! I have not had to replace that yet luckily.
@@larsonhomeinspection9932 is there a way to descale the 3 way. My guy said that could be why it stuck in heat mode and could not get DHW
@@dukekraus4362 I would think the 3 way valve would have to be removed and cleaned. But yes, regular descaling can prevent this
This is an excellent video. I have an NTI condensing boiler. But I don't think it has a domestic hot water side. The boiler water goes into a heat exchanger???? But wouldn't that setup result in a lot more corrosion? Because new water is always being introduced? Sort of confusing. I have well water. Lots of calcium and rust. Nobody in this area seems to know how to flush these things and it's hard to find a service tech. I had a recent service but they didn't flush anything. It's also hard to figure out where the pump should go. But I'll probably need to do it myself. I get Kettling or banging but only after I take a shower when it's cranking up. If I shut it down for 10 minutes it seems ok. But this is a great video. Thanks.
Thanks! The boiler water heats the domestic hot water by means of a double plate heat exchanger, which keeps the boiler water totally separate from domestic. The boiler water stays in the system in a closed loop. They tankless water heaters are pretty particular when it comes to water quality. But if your on well water, they just should be flushed more regularly. Pre filters and softeners will take out iron. It is unfortunate a lot of plumbers dont seem to know or care about flushing them.
Im still having problems with my condensing boiler. Its different than yours. Mine only has one in and one out. Its not a combination boiler. The funny thing is i only get banging after i use hot water. It does not happen when using heat. I cant figure out why it only happens with hot water. The line divides after the boiler. When there is a call for hot water, a valve shuts off the heat. When the hot water tank is up to temp, the heat valve opens. If there was blockage inside the boiler, i would think it wouldn't make a difference. I dont know why the flow would be restricted to the hot water tank. So im still working on it. Still unable to get an HVAC guy to check it.
How did you handle the condescence line and the do's and don'ts.
thanks for the video! a few questions here, "turn off gas and call for heat to open 3 way valve" is this the only way to open 3 way valve for flushing space heat side? also do you have to bleed air out after flushing vinegar out of system?
I'm not sure if there's a manual way to open that 3 way valve. The 3 way valve is what commonly fails in these units. No you don't have to bleed air. Just shut off the valves. The boiler automatically purges any air in the system.
Good video.. I subbed
Thanks!
Great video. With your help I was able to flush my Navien NCB240 system. Could you elaborate on how to put Boiler & Heating System Cleaner into the baseboard heating system. I could depressurize the boiler and add the Cleaner but on boiler startup and "Air" removal would the Cleaner not be blown out onto the floor? How did you do it? ... Thx
You could pump it in with a utility pump/garden hose. Or you could drain fluid on one side of the system to create suction/siphon in another location. Then pour the boiler cleaner in the hose connected to that hose bib.
Nice video I am looking to install one of these in my home to replace a boiler from 1963 and even having been an HVAC service person and pipefitter I was not 100% clear on the maintenance required so thank you for the video. Do you like the combi boiler and has it worked well for you?
Great to hear! Yes, its not common knowledge. I love the system. There are some hot water sandwiches sometimes, but I've never had any other problems. Our local city wasn't even allowing combis for some reason. They are not much more than just the boiler itself. Navien have a great reputation.
Great video. Thanks much. At the end of your video you flushed any remaining vinegar in the space heating side with water from the domestic cold side. I thought I was doing this step right, however, I accidentally opened the space heating cold supply for about 30 seconds and flushed. After realizing my mistake, I shut the space heating cold supply off and proceeded to flush with the domestic cold supply. Did my mistake introduce fresh water into the space heating side?? If so, will this cause problems and what can be done about it? Thank you again!
Thanks! Adding a little fresh water won't hurt a thing
Great detailed video. I have few more questions thou. When is best time to flush/ maintenance boiler, ie winter or summer. Also don' t need to clean air filter?
Thanks. Best time is off season. Yes, there is a screen on intake that should be cleaned
@@larsonhomeinspection9932 Thanks for the reply, as non professional, this type of how to is really helping me and people like me. Also video 5.57 after you cleaned condenses pipe, you said you need refill condenses pipe with water, (including bleach). My question is why do you need refill it with water? and if I refill it do i use same hole to refill (ie where you squirt blech?) thx
Do you need to flush the space heating side of the unit?
Great video!
you have an electric outlet right next to the water drains and hoses...is it a GFCI outlet/circuit?
Thanks! No that's not required for a boiler. Not a bad idea though.
@@larsonhomeinspection9932 True. it is not needed, however a surge protector is warranted as it is a electronic system subject to power surges
Hi, in your video, you said you have to fill the water to the spaceheater system without air, i was wondering what that process is going to be but your video stopped while you flushing the spaecheater system with public water. my question is, what's next step? do you have to fill it up manually? or just disconnect the hoses and the unit will fill the system by itself after you turn back on all the valves? thx again for the great video.
My spaceheating (secondary) loop to the house was already filled with water. I isolated the loop from the boiler so I could flush just the boiler. Once you're done flushing the boiler, you can just close the hose bib valves, and open the primary loop (spaceheat) valves. The water will stay in the boiler. To fill the whole system, you hook up a city water supply (washer hose) to a hose bib on the supply side loop, isolate valves below it (isolate secondary from primary) , open a hose bib on the return side loop to allow air and water to run out, and run water through the loop. Once it's flowing only water, close the valves. An air scoop and air separator should be installed on the supply side, and a purge in the boiler itself will eventually eliminate the air in the system. I just meant you don't want to drain, and refill the water in the spaceheating system often, because it reintroduces oxygen to the boiler water.
Great job on this video. Was not sure on which step you mixed in the Hercules product? Did you at one point mix it into the bucket with the Vinegar to flush and descale? I noticed at 9:25 of the video the water started turning from slight blue to slight pink/red I assume that was the Hercules being circulated cleaning the system along with the vinegar? Thank you much appreciate you posting this video. Cheers!
Thanks! I should have clarified; the system already had the Hercules in the system before doing the flush. I add a bottle and leave it in the system. You sure could add boiler flush to the vinegar for the space heat side flush. The flushed water that came out is pink due to the Hercules flush in the water, and my system had orange antifreeze in it at one point.
To add boiler conditioner : I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system.
RE: the screen for the space heating side - I want to check that screen. So I just need to turn off the two isolating valves for the space heating ? (thanks for posting the video - very nice). [I just called a service guy and asked him to do all maint., but all he did was domestic hot water - he ignored anything related to the space heating side, I did not realize it at the time,. but i do now!]
Close the isolation valves, open that pump drain petcock to drain some water, then you can take it out.
great video, im having a problem with flushing my combi boiler. DOmestic side was no issues, but the main heat exchanger does not circulate water almost as if there is an internal valve that is shut off. any input would be much appreciated. thanks in advance
Probably stuck 3 way valve
Question about the closely spaced tees - what purpose do they serve? It seems like it would be less efficient to have cool water potentially bypass the boiler and go straight back into the space heating system. Why isn't the boiler installed inline so that all water circulated through the space heating system must pass through the boiler?
Great question. Modern high-efficiency boilers have a much lower flow rate through their heat exchanger than cast iron boilers. The tees are a hydraulic separator to allow the flow through the primary loop to be higher than what goes through the boiler. Also, if there were a blockage or valve shut in the secondary loop, it prevents dead heading, and allows boiler pump to circulate water freely.
The pumps and pipe sizes are calculated so all of the hot boiler water goes into the supply side and doesn't recirculate back to the return.
I am a contractor who installed the 240 NCB. Got no heat but have DHW. Wondering if I need to clean as you did probably? I have no error codes that is what is confusing. Will talk to Navien later today. Thanks
Im guessing the 3 way valve is stuck. Flushing can prevent that problem, but might not fix it once its stuck. Worth a try. Or maybe tap on the valve?
Thanks for you video in the detail. I have one question. The first part with domestic Hot water wasn't any problem, but for the second part (heat exchanger) my pump didn't circulate . Water didn't came out from red valve. Please tell me what need to do that my pump can start circulating?
There’s a three way switch in the unit. Once you’re done flushing the hot water side, turn the unit back on and set the thermostat to call for heat. Once the boiler is in heating mode then turn off the gas. This will cause the unit to shut down with an error message which is fine. Turn off the power and you should be able to flush the heat exchanger.
@@iansnape2646 No need to turn off the gas. Once you call for heat and the Navien has started heating that zone, simply kill power to the Navien. The 3-way valve will be open on the space heating side (rather than the domestic hot water side), and you can then flush the space heating side of the boiler.
Good video. You didn't have to have your thermostat call for heat and swing open the 3 way valve before flushing the heat side of the system? Is this a necessary step or am I overthinking it?
Yes that might be necessary. Didn't need to on mine or it was already open. Great question!
You mentioned a boiler conditioner. Could you explain how and when you added that and clarify what product you were using?
Hercules Boiler cleaner. I added it to my boiler antifreeze and pumped it in the system. You can also open a drain valve on one side of your loop to drain some water out, and then open a drain valve on another side, which will suck air in via siphon, and pour the cleaner through a hose so it sucks it in.
Great video! I hope you can help me as my "certified" Navien tech doesn't have a clue. I stupidly waited too long to descale my NCB-210 and the DHW side is fine but my Heating side is quite sick. When I try flushing with the pump on the cold side I get NOTHING out of the hot side. Reversing it I get good flow. When I run the system the loop gets hot but I am getting a rhythmic knocking almost like the sound an old sailing ship makes as is moves in the water. I have tried vinegar and commercial flush. Is my heat exchanger toast? Thanks!
@@aliencivilizationn Hello... My final fix was replacing the, 3-Way valve. A bit of a bitch to get to but an easy procedure. Only about $35 on Amazon or Supply House. The latter a fantastic source for HVAC stuff. Good Luck!!
Good! It fixed my issue and even though it was hard to get to it saved me a couple of hundred bucks doing it myself. You might have leaks at the union under the valve so take care to use tape & sealant and use silicone grease on the union washer...
how would you go about purging the air out of the baseboard in your home with this unit?
I have the exact same combi unit that does both domestic hot water and radiant heat as you have in this video. If I wanted to purge the air out of the 4 zones I have what would you recommend? My question first off is, do I need to shut the iso valves on the domestic water side or do I leave them alone? 2nd question is do I need to shut off the iso valves on the boiler side or leave them open too? 3rd question is should the unit be on or off?
anyways as far as purging the loops, I have 4 circulator pumps for the 4 zones. Lets say I am doing the first zone, would I close off the other 3 zones at the pumps I am not purging and on the return side, would I also close off the 3 zones I'm not purging? I know you have to hook up a garden hose to the spigot and open the hose bib on that zone and let the air escape. my last question is right after the return manifold before it goes back to the boiler, theres a ball valve. Does that stay open or closed? Appreciate any advice you would have to offer
ya, hook up a garden hose to introduce, and have a garden hose on the end of the loop purge valve to remove air. Purge each zone individually if you can. Let the water run through that zone and flush the air/water until only air comes out. Doesn't matter if the domestic or boiler valves are closed. Some systems have little air purge bolts in the radiators on the upper level to remove air.
Hi,
I've this unit Combi about 3 years and did not maintenance regularly because the contractors/builders did not tell me (new house after one year they're gone). Recently, I paid a plumber $250 to flash heater exchanges did not flush a space heater. $450 to replace 3 ways valve. Your video very helpful. DIY save lot money. I wanted to try and I am worry about air inside the system. How to purge? etc... Could you give me more info./details
Thanks
hook up a garden hose to introduce water, and have a garden hose on the end of the loop purge valve to remove air. Purge each zone individually if you can. Let the water run through that zone and flush the air/water until only air comes out. Some systems have little air purge bolts in the radiators on the upper level to remove air. Your system should also have an air scoop and air eliminator/separator to constantly remove air out of the system.
Great video this is my exact unit and it helps a lot. I also have the same issue where my auto feed water 3 way stopped working after year 4. It is a cheap part to replace and I might try that after the winter. It isn't that difficult to pressurize the unit on the heating side without the auto feeder, but these steps helped. If it shoots up super hot it means there is not enough water from my experience. @@larsonhomeinspection9932
Great video. How do you refill the space heating side of the heat exchanger once you finish flushing cold water through it? I tried just turning on my unit and the auto feed refilled it but then I had a ton of air trapped in my system. Thanks
I have the same question, the video ends before that side is refilled with water. At 8:45 you mention that boiler water is filled and never drained and you don't want to introduce new water but if your draining water out of the unit on the space heating side, don't you need to replace it with new water?
I too am dealing with this issue with my mom's boiler. I was able to download the "Quick Installation Guide" and there it states that you must remove the air vent cap before refilling the unit. Then you are to replace the cap when the unit is full. That's all well and good, but, how do you know when the system is full? Will water come out the top of the air vent? That's my guess but it would be nice to know one way or another. Another issue I had is when I removed the cap, a whole bunch of really small fiber/paper washers/O-rings fell out of the cap. Be careful with that as I don't know what order they're to go back in. If anyone here has gotten an answer, please share. Thanks
The boiler is isolated (valves closed) from the rest of the system when I am flushing it. So most of the water stays in the branch lines. Shut the outlet valve before you turn off the inlet valve so the new water stays in the heat exchanger.
@@eddiemarano9998 yes air comes out of that vent cap, and when water comes out you know it's full. It constantly purges air from the system.
How do you open the 3-way valve to flush out the space heating side of the DHW exchanger?
By turning the thermostat up to call for heat. With the gas valve off
I have lasts endurance for both domestic hot water and heating. Does it need to be flushed? Do you recommend switching to these navien in future.
any tankless water heater should be flushed every year or 2
Great video. Question - you mention not to introduce fresh water into the boiler side. However, doesn't it get introduced as part of the boiler flush?
A little bit. Boiler side only flush every couple years.
Thank you. I did mine yesterday. The video really helped me. How do you add inhibitor on the heating side? I have copper fin baseboard. Should I add it?
@@desigoose definitely. Drain some water out of one port, open another port with a hose attached so it will create suction through siphon. Pour inhibitor into hose. Or pump it in.
Thank you
You stated after you flush the heater side of the navien you should allow air into how to you do that.
hi, so if you have the domestic side valves open, it doesn't affect the left side inlet and outlet? i see you were doing the vinegar pump while both of the domestic valves were open. so, opening the valves on the domestic side and then opening the service valves on the left side, the water from the right domestic valves won't come out of the left boiler side outlet?
they are 2 different systems in one unit. the water takes different paths. left side which is space heating is a closed loop.
@@Jallelab99141 correct
I have the same system. Had no problem doing the domestic hot water side. On the space heater side I open the service valves close the isolation valves, cleaned the strainer, open the drain plug . Closed the pump drain plug reinstalled the strainer. Installed the pressure line from the sump pump that’s sitting in my bucket with water and descaling solution and I’m not getting any water to come out of the other side. Pump is working I checked that. Thought I had some type of “vapor lock” going on so I shut down the sump pump took the strainer back out and only a little water came . What’s going on? Any help would be appreciated
I think the answer is provided by the author in another comment .... "Turn the gas off to the boiler, turn the power to the boiler on and turn thermostat up so it calls for heat. This will open the 3 way valve"
I accidentally drained the water in the non-domestic side and the pressures dropped. How do I refill the water on the non-domestic side?
My combi unit does not have the service ports on the space heating hot water sides. This seems like a major install error. is that correct?
Yes they should have definitely installed them
@@larsonhomeinspection9932 So if there are no service ports on the space heater side, there's no way to flush, even if you get the 3-way valve to open? Because that simply routes the space-heating loop through the isolated plate exchanger? If so, my option is to either get them installed or flushing the whole hydronic loop...
@@autonomy5649 correct
How did you get the boiler flush into the system. When did that happen?
I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system. One quarter of the boiler conditioner/flush. Or you could pump it in with a pump.
I have the same system and the heat side seems to be air locked. Can you do a video on how to flush out the heat distribution side of the system to get airlock out?
hook up a garden hose to an inlet, and have one on the outlet, run water through until all air is gone.
Where is the cold water inlet for the closed loop space heating side? Does that inlet need to always stay open since that system is a closed loop? How do you add water to the closed loop side?
There is a port on the far right of the unit to introduce water to the space heat side. This should be piped to domestic water. This one has an auto feeder to introduce water when it gets down to a certain pressure, so yes it is always open. Or can use a garden hose on a purge valve.
I follow your video step by step to flush my system. On the hot water side, it went very well, but when I switch to boiler to flush the heat exchange it was lock up. I can not flush. It seems like the 3 ways valve was close the heat exchange. Would you please tell me what I should do to open the valve in boiler side so I be able to flush the boiler heat exchange. Thank you.
Turn the gas off to the boiler, turn the power to the boiler on and turn thermostat up so it calls for heat. This will open the 3 way valve
VO NGUYEN did it work? I’m having the same issue
@@larsonhomeinspection9932 In my experience from doing this process yesterday, there's no need to turn off the gas. Once you call for space heat and the Navien has started heating that zone, simply kill power to the Navien. The 3-way valve will be open on the space heating side (rather than the domestic hot water side), and you can then flush the space heating side of the boiler. Note that I kill power to the Navien at my circuit breaker panel, not from the front panel of the Navien. Not sure if that makes any difference.
I have Navien CH-240 and lately the domestic water isn't heating unless I go downstairs and turn on the closest hot water tap which is my laundry tub. I turn it on the heater kicks in to generate some hot water. This has just happened recently. Any suggestions why this is happening?
Probably the flow sensor
I have had my combi boiler for just over a year now and will be flushing it shortly. My question for you is regarding operation. Do you ever lose hot water when using the shower? I have a clawfoot tub with individual hot/cold valves that has never given me a problem, and a stand up shower with a mixing valve. Mixing valve is fully adjusted to let maximum hot water temp through. My shower head is 1.75gpm, which I know this boiler requires .5gpm in order to start heating. Shortly after running the shower with the handle turned fully to hot I will lose hot water and it will be freezing cold. I find that when I turn on my bathroom sink's hot water I regain hot water to my shower. I will be contacting navien for answers as well, but just wondering if you've experienced anything like this.
iamtheed hello
That is unusual. No I've never had a drop in hot water. It may be your mixing valve or something wrong with the tankless controls.
How do you air out of the space heating side lines? I got air in lines last year
ya, hook up a garden hose to introduce water, and have a garden hose on the end of the loop purge valve to remove air. Purge each zone individually if you can. Let the water run through that zone and flush the air/water until only air comes out. Some systems have little air purge bolts in the radiators on the upper level to remove air. Your system should also have an air scoop and air eliminator/separator to constantly remove air out of the system.
You are freaking me out, you sound like AvE if he had a swear jar.
Haha, he's my idol
I did this to my navian 240 combo tankless today and my water will not get hot now. Any idea what’s causing this? It was fine before
probably air in the system
My plumber just installed one ncb240 for me, we have not start the unit yet. my spaceheating supply line is smaller than yours, will this be an issue?
Andy Larson my plumber install 3/4 line from the boiler and then 1 inch when it intercept the close t. I have four zone valves with one circulation pump, four bathroom three kitchen with 2300 square feet
Right off the boiler? It should be at least a 1" pipe. Then it goes into a 1-1/4 pipe for the closely spaced tees. This is Navien's recommendation. If you have a small house with only one zone, a 3/4 might be ok. Could you post a pic?
I believe that's undersized for 4 zones and a house of that size. Four 3/4" zoned pipes would require a 1-1/4" primary pipe for proper flow. It will likely make the pumps work harder (more head loss) if multiple are running simultaneously, and will increase the return temperature, thereby reducing the boiler's efficiency.
The supply and return connections on the boiler are 1", so I don't think it's good to reduce it to 3/4".
How do you inject the boiler conditioner into the boiler side
I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system. One quarter of the boiler conditioner/flush. Or you could pump it in with a pump.
Ive read that Navian doesn't recommend servicing the space heater side.
I came across a UA-cam video that said the same. But there are other videos that show the space heater side being flushed. It's a real shame that Navien doesn't document descaling/maintenance processes in the user manual. And their not inclined to help if you call them directly as a homeowner.
OK why the boiler side is dirtier if is a close loop system
Good question. The flux paste/solder and dirt stay in the system in a closed loop. In an open loop, they get flushed and cleaned out with clean water. Also, my system is pretty old and had antifreeze in it, which also added sludge and color.
After flushing the unit my preset temperature fluctuates. I have preset 140F for heater and 120F for domestic water and how it fluctuates between 138 - 144F and 118 - 126F. I believe before it was accurately holding 140 and 120. Any suggestions on how to fix it?
Sorry, I'm not sure.
@@larsonhomeinspection9932 after you flushed heater side, you just rinsed with water for 5-10 min by connecting to domestic cold water and then closed the maintenance valves , turning on system valves and that's it? Did you needed to do anything else?
Ruslan Nikandrov it all depends on the load it will fluctuate!
i descaled my combi unit and now the psi is reading 0.00/ e351 error code seems like its not getting water pressure . any ideas what causing it
probably air in the system
Good video. Very helpful but I’m having an issue. After I flushed the system and did everything you did I started getting and E 016 error code (overheating heat exchanger) not sure why. Air in the system maybe? The unit boots up fine but when I turn the hot water faucet on the system starts to heat up, then starts to knock and then goes into E016. Any suggestions would help. It’s been 4 days with no hot water😫
jimg81 bummer, but that's not enough information to diagnose the problem
The water heater side? That is unusual..must be air in the system. Did you figure it out?
I can't believe you soldered everything. Was this your 1st one?
My Pennys It was. I'm not a pro plumber. Don't have a pro press!
Lol I'm not a pro plumber either! I was only introduced to propress at work, we use it, I love it. You did an excellent job. I just can't believe you had to solder all of that lmao! Thanks for the video, very useful to me.
I remember my first combi like it was yesterday. Really it was like a couple months ago lol
My Pennys thanks!
My Pennys ya, it's fast, but they haven't stood the test of time yet. After all it is just an o ring, and rubber breaks down. Solder lasts!
How do you get boiler flush into boiler side?
I had a 4' washer hose installed on a purge valve for inlet, and another hose at the end of the loop. Opened the end loop valve to drain water. This started a siphon on the inlet, so I could pour the conditioner directly into the garden hose (holding it above the valve) which would get siphoned into the system. One quarter of the boiler conditioner/flush. Or you could pump it in with a pump.
I don't understand your comment, "Another step I didn't do is to open the 3 way valve when flushing the space heat side to make sure the space heat and domestic plate exchangers get flushed." Which 3-way valve? Do you mean the valves that you closed to isolate the space heat plumbing from the vinegar during the flush?
Also, isn't there an air filter at the top of the cabinet that should be checked/cleaned?
I mean by making the unit call for heat, and call for DHW, it opens the 3 way valve for that heat exchanger. So basically flushing on the heat side, while making the unit call for each system to flush each heat exchanger. Probably not necessary.
Yes there's a intake screen filter.
@@larsonhomeinspection9932 OK, thanks. Another question: When I watched my HVAC guy clean the boiler last year, I saw him unscrew the probe that goes into the burner (near the little window where you can see the flame when the system is running). He then scraped the tip of the probe clean. I don't see that in the Navien maintenance documentation. Do you have an opinion on that process? Good idea?
@@sgoldste02Haha I'm not certain if that's the best way. Cleaning the flame sensor.
@@larsonhomeinspection9932 Thanks for the great video! I had no problem flushing the domestic hot water side, was gunky after 2 yrs of operation. I attempted heating side but have the navien supplied manifold under the boiler. Took me a few to realize there are two small screws on the side of the heating flush ports to open/close them. Earlier in the comments you only mentioned calling for heat, now you say heat and DHW. I attempted flush with just heat and while the openings in the flush valves are small, it didn't seem like it was flushing anything after about 15 minutes so I quit. Please confirm I need to call for heat and DWH to flush correctly. Do I shut off supply to DWH so I'm not running water all that time?
@@larsonhomeinspection9932 Haha, I just did this procedure again yesterday, and ran into the 3-way valve situation. I was able to flush the domestic hot water side with no problems, but when I switched over to the space heat side, I couldn't get the vinegar to flow through the unit. So I powered up the boiler, made a zone call for heat, then powered the down the boiler again. That worked and allowed me to flush the space heat side of the boiler.
I have hot water but no heat can you help ??
Try to remove and clean 3 way valve
Hi please help me I’m a single mother/homeowner and my unit doesn’t have heat. What steps should I take to fix this without calling a plumber.
Jennifer A. There should be error codes on the boiler. You can look them up in the operator manual. Other quick things to check are if the power's on to the unit, and if the intake or exhaust outside are blocked with snow or ice. Does your hot water work?
Larson Home Inspection possible water damage to the circulator pump. No error messages on the box
You should hear or feel if the circ pump is working. I suggest calling a HVAC tech asap. Hard to diagnose via messages.
Larson Home Inspection thanks will do!
Are you a contractor or you're just doing this for your own home?
I am not a contractor. Just did this in my own home.
@@larsonhomeinspection9932 well damn! you seem to know everything about it. even my current HVAC guy who only works on the classic tank and furnace type boilers and heaters says he dont want to mess with no navien box so, kudos man!
@@shilezi thanks!
To messy couldn't understand very well didn't explain what to shut off what to hook up anyway thanks for the video
JiJi Mu'mens ON sorry you felt that way. Yes, this job is not for the faint of heart. You need to have a basic understanding of hydronics and the valves. The video would be an hour if I explained everything.
I'm a handyman and trying to learn this knew system my site is bringing but your video was not to helpful for me at least but like I say thanks for the video and take alot to do so and patience .
No way to have one of these systems with our well water! Seems like the descaling could eventually be built in to these units as to be semi-automatic...
I have hard water I put a home softener system first
do you have an private email I can ask some questions I just installed 100,000 btu navian combi. have some questions bout start up and some others
call 8005198794 option 2
This guy is AvE right?
My Rheem Combi maintenance instructions suggests flushing at 4 GPM, or 240 GPH. The Wayne 1/3 HP sump in your video has this spec: "High performance; max. flow rate is 4600 Gallons Per Hour; 3060 GPH at 10 ft. of discharge lift". I know your unit is a Navien, but is there any concern that the sump pressure could damage the unit?
*BUMP*. Rheem says using a sump pump (like the one in your video) could destroy the unit. Another contractor says he uses "Everbilt non submersible transfer pump. 6GPM". What do you say? Isn't the responsible thing, for the benefit of others who may follow your instructions, to respond to my inquiry?
Navien Support 2
11:51:03 Thank you for contacting Navien. How may I be of assistance?
Dan
11:51:51 Hi, I'm looking at the NCB-240/130H Combi. I don't see a recommendation for GPM flow rates when doing flush maintenance. Can I safely use any sump pump, or is there a recommended upper limit on flow rate?
Navien Support 2
11:52:43 normally any smaller size pump would be fine 1/8 and about 2-4gpm should be fine
Dan
11:54:49 OK, but could the unit be damaged by using, e.g., a Weber 1/3 HP sump (50GPM)?
Navien Support 2
11:55:20 that would be a bit too strong.
Above is a conversation I had with Navien about this very unit. I'm disappointed that Larson hasn't responded to an inquiry about what could be a very serious issue.
@@danmorton9461 I don't check youtube comments very often. Sorry for just getting to this. I don't make money off these videos, just for information. I'm not a substitution for a technical support tech from the company or for a plumber. I wouldn't worry too much about how large of a sump pump gpm. Think about how many gpm come out of all your fixtures in your house when they are all on.
Seems like a high maintenance pain in the ass...is it worth it vs a regular boiler???
I have hot-water baseboard heat in my home, one hvac contractor is trying to sell me a high efficiency Bosch 96% combi gas boiler to serve my baseboard heat AND personal hot water for showering, tubs etc.
Another hvac contractor tells me the Bosch combi will never make enough hot water for the household, it requires a lot of maintenance and suggests a regular 85% gas fired boiler.
Also, how many gpm of hot water does it produce for bathing etc?
.Get a combi! Definitely worth it. Two for the price of one. Not sure on Bosch, but the navien ncb-240 is 200,000 btu with 4.5 gpm flow rate. We can take 2 hot showers in MN winter at same time no problem. Youdont haveto flush the boiler every year, just the domestic side. I would take an 10% efficiency gain, and basically a free tankless water heater for the same price and install time. Also saves a ton of floor space.
I have a combi Navien. No problems heating a large 3 story old house with old cast iron radiators. It also handles our hot water. No problem even running 2 showers at once it keeps up plenty fine. I honestly find upgrading my old style boiler and old style water heater to the tankless the best investment I've made yet. Summer gas bill is about 25% lower and winter gas bill is about 10-15% lower.
Good video .
Joaquim de souza thanks!