Pretty clever! I just put in a Takagi tankless and had a similar situation with the vent - had 6" single wall flashed to the roof with a 6 to 4 metal reducer. I ran 3" PVC and used the 4x3 reducer with the stop removed to bear on the tapered part of my metal reducer. I capped that with a slip over rubber collar to flash it.
Great video it is exactly what i needed to know, as i am replacing a 40 gallon tank heater with a Rinnai RX 180 IN condensing unit it is an indoor/outdoor convertible model. If you are familiar with that model, will you procedure as stated in your video work for me. It will be installed in an exterior water heater closet with a vented door but i want to run the exhaust through the roof flashing as you did in the video, the the roof existing roof vevt is very shirt only about 4 feet from top of old tank to top of old termination cap on roof. Thank you so very much. Greg
You don't keep it out, It goes down through the unit and goes out the condensate drain on this particular unit. Each brand has their own way of dealing with this issue. Thanks for the Question.
I just had a navien installed (Model NPE-150S2), and the vertical pipe looks like absolute dogshit coming out of my roof; is there some way to finish it to make it look better?
That T up top looks like it would let rain come down and into the water heater. All it's gonna take is a little wind to blow it right into the vertical pipe. Also, shouldn't the intake have a pipe with a screen in it to keep critters out?
Hi Don, The manufacturer's instructions call for a T on top. So, that is what we put there. As to the screen, there is a screen inside the unit that does that. If too much resistance is put on the intake, it will upset the heater. Thanks for the questions.
As a plumber, I am impressed with the idea of using the reducer to act as a Stop for the b vent storm collar. Pretty slick. But out of curiosity, why didn't you just use a 3" PVC concentric vent kit? That way you could get your makeup air from outside and not worry about creating a back draft through the heat exchanger in the winter. I ask only because I like to hear how and why other plumbers do their thing.
Navien doesn't recommend using the 3" concentric vent kit. And we are after all in South Texas. Back drafting isn't really a problem here. Also Navien has a damper in the exhaust to prevent backdraft. I could have simply transitioned to 3" withing 1' of the top of the heater, but I wanted to do the video on this job. My supplier of Navien asked me why I didn't do that & My answer was that in this instance, it would have been fine, but on a long run, the 2" pipe & fittings are a whole lot cheaper. And just as a final note, if I had gone with the 3" concentric, I would have had to wait for it to come in. They are scarce as hen's teeth in our area. Thanks for the questions.
@@adventuresofthatplumberdud9326 im venting a couple of Naviens tomorrow. I have the concentric kit coming tomorrow. It appears you're using regular schedule 40 PVC, I see their manual says that's permissible but then they go onto list a bunch of brands approved for use with their units. It's a little confusing. Are you just using clear PVC cement and making sure the line has proper fall back to the heater if you run horizontal?
I need to do the same thing for a condensing Navien NPE-240A2, but my existing B-vent runs from the garage, through the second story wall, and out the roof. The B-vent is a straight run, but I probably can't easily remove it. Can I leave it in place and use it as a chase-way to feed approx 20 ft CPVC pipe down from the roof to connect to the Tankless WH? Is the CPVC pipe likely to rattle around inside the B-vent? The CPVC pipe could be secured/supported at the tankless WH, the garage ceiling, in the attic, and at the roof. Is that enough to pass an inspection, or do I also need to open drywall in the second story to add a support? Should I stick with 2" CPVC pipe so the volume of hot gas gets pushed out the stack before it cools and CO descends back down the pipe and into the garage? Or is this approx 20 ft length better served with 3" pipe for less resistance? Does CPVC need to be allowed to expand lengthwise like the old B-vent?
Sorry for the slow reply, The pipe that comes off of a Navien is 2" PVC, and it is possible to do what you are asking, but it will be a tight fit. 2" PVC will barely fit inside 3" B Vent.
My inspector said prove that you can take the intake air from the attic. Seems obvious that a 1300 sq ft house with a 2x8 roof and 2 1x3 vents are each end would easily provide the intake air for a 2 in intake pipe. Can you help with some calculations.
Sorry for the slow reply, I just noticed there were comments that were unanswered. I would ask him to show me where in the code it says I can't. I can tell you that on a Navien, the manual says you can, provided there is adequate ventilation. Good Luck.
We didn't reduce the exhaust, please watch the video again. it is one piece of 2" Pipe from the heater all the way to the T on top. the 3"X2" reducer is an adapter to make it fit the existing roof flashing.
@@adventuresofthatplumberdud9326 i see, Original Pipe was 2" so you used 3" adapter to fit it on to the roof exhaust without having to modify! i got confused because my its a 3" from unit to roof and actually the Id its bigger than 3" something like 31/4 or so so i just added a Coupling to the pipe and it fit right in not on the outside but on the inside without even touching the existing exhaust
I'm planning on adapting your solution for the NPE-180S I'm installing. I'm in N. California with average rainfall and little to no snow. Couple questions: 1) How do you determine the length of pipe protruding from the roof? Reading the comments I'm still a little unsure about the termination with regard to rain. From the Navien Installation and Operation Manual, NPE Condensing Water Heaters, v5.3 (May 29, 2019), pg. 34: "To avoid moisture and frost build-up and to maintain clearances to openings on adjacent homes, 45 degree elbows, 90 degree elbows, or tees may be attached to the end of the termination vent pipe to direct the exhaust plumes away from buildings, as long as the total allowable vent lengths, maximum number of elbows, and distances to air intake restrictions are observed." 2) Any concerns using a 90 degree elbow for the exhaust vent to keep rain from entering?
The length above the roof should be 18"-24". We always use a T on too of the vent pipe. In the off chance some rain does fo down the vent, it is directed down through the burner assy & comes out the condensate drain. I have seen them improperly installed with nothing on top & they worked just fine. The 180S by the way is the same setup as the 240A. I would however suggest that you go with an A model.
How can you use PVC for exhaust? What are the temps coming out of that? You'd think they would be pretty high, above 200F exhaust gas temp. We just got a Takagi and it says you have to use Category III.
The temperature of the exhaust coming out of this unit is around 100 degrees, that is well within the limits of PVC pipe. Your Takagi isn't a condensing unit, therefore you must use category III Stainless vent pipe. This unit reclaims 99% of the heat generated by the burner. Yours will reclaim about 70%-80% of the heat. That is just one of the many reasons we think Navien is the best heater on the market.
Thank you for the video. Is it a good idea to run the PVC pipe thru the exist Type B vent all the way up to tip of the B vent? This way no need to remove the exist B vent. Thank you
Sorry for the late reply, I had no idea that I had comments. No, it is a corrosive exhaust and would quickly deteriorate the metal vent. The manufacturer states that it must be PVC or ABS pipe.
When we started out, we were not, just putting the grid piece that comes with the heater, but now we put a street 90 in the intake & put the grid in that. I figure that way nothing can fall into the heater.
why didn't you put a plastic screen or something on the pipe you did with the original flashing?? wont squirrels and other thingks like birds try to get in there??? we have all kinds of squirrels and small birds around my area. no way i would leave those holes without screens plastic or another type screen.
If you mean the original flashing, we reused that hole and put 3" PVC Pipe through it. If you mean the outlet for the water heater, we do install a plastic screen that comes with the heater. You have to e very carful when covering these vents, if you put too much backpressure on the heater, it will stop working & throw an error code.
I have a navien combi unit , it is in my basement. Can I vent it to my roof? It is currently spitting out the side of my house. Any ideas would help greatly, thanks 🙏
With Tankless, there is no thermal expansion, so an expansion tank is no necessary, However, your town or jurisdiction may require one, and if that is so, then he needs to add one.
so the gas line that fed the original tank water heater was sufficient to supply the tankless? the tankless heaters are usually about 5 times the btu of the tank heaters
Yes sir, there was a 3/4" gas supply already there. But just for future reference, Navien heaters can run on 1/2" supply under most conditions. Thanks for your question.
My installer did not use a sanitary T at the top of the vent pipe on the roof. He used a 45 degree elbow with a plastic screen. I have a little concern about rain water entering the unit and causing damage.
He should have used a Tee, that is what the instructions call for. If water does enter the unit, it should be channeled into the condensate drain, but if it is a really hard rain, it could overwhelm the drain and cause damage to the unit. I would definitely get it changed.
If it is in an installation that isn't used often, such as a beach house, I would suggest screens. But this is a single family home where the heater gets used frequently.
B Vent can't be used on a condensing Tankless water heater as corrosive water condenses in the vent. Plus the Manufacturer specifies PVC pipe as the vent material.
@@adventuresofthatplumberdud9326 Gotcha. That's what I thought aswell until Noritz came out with the EZTR50 Bundle. Has the exhaust vent tieing into the existing HWT venting.
We always do. This was not a complete installation when we shot the video. Hurricane Harvey came through shortly after we installed this heater and had no leaks from that.
I am not sure what you are saying here. We didn't use the old vent at all, just the roof jack. Been doing it this way for about 5 years with no issues whatsoever.
Navien requires a T on their exhaust, If you go above the roof with the intake, it requires a candy cane. If you take combustion air from the attic as we do in Texas, you can just put a 90 on top of the heater.
Terrible plumbers give us HVAC guys bad rep that was awful install and need to follow venting in navien installation manual at least new flashing for pvc venting and you are supposed be using cvpc schedule 80 on exhaust and supposed use an intake for combustion air what are you guys chuck in a truck would not be proud. Of that install terrible hack city
Well Brian, it is very obvious to me that you are not at all familiar with Navien Water Heaters. They do not require schedule 80 CPVC pipe for their vent, in fact, schedule 80 CPVC won't even fit the vent collar on top of the unit. So, maybe you should stick to doing HVAC and leave the plumbing to the professionals.
Great video it is exactly what i needed to know, as i am replacing a 40 gallon tank heater with a Rinnai RX 180 IN condensing unit it is an indoor/outdoor convertible model. If you are familiar with that model, will you procedure as stated in your video work for me. It will be installed in an exterior water heater closet with a vented door but i want to run the exhaust through the roof flashing as you did in the video, the the roof existing roof vevt is very shirt only about 4 feet from top of old tank to top of old termination cap on roof. Thank you so very much. Greg
Pretty clever! I just put in a Takagi tankless and had a similar situation with the vent - had 6" single wall flashed to the roof with a 6 to 4 metal reducer. I ran 3" PVC and used the 4x3 reducer with the stop removed to bear on the tapered part of my metal reducer. I capped that with a slip over rubber collar to flash it.
I have been doing plumbing for a long time and I never seen that tool before. That is pretty handy
I guess you haven't been doing it long enough...
Yes, they have been around for many years. They make them from 1" all the way through 4" for sure. a bit pricey, but worth the money.
Very cool video! You can also use spray paint to help the exhaust vent match the color of the roof.
Great video it is exactly what i needed to know, as i am replacing a 40 gallon tank heater with a Rinnai RX 180 IN condensing unit it is an indoor/outdoor convertible model. If you are familiar with that model, will you procedure as stated in your video work for me. It will be installed in an exterior water heater closet with a vented door but i want to run the exhaust through the roof flashing as you did in the video, the the roof existing roof vevt is very shirt only about 4 feet from top of old tank to top of old termination cap on roof. Thank you so very much. Greg
Fantastic video. Ty
You're Welcome, Thanks for the compliment.
i like what you did with the vent through the roof.. I was just wondering how you keep moisture out the exhaust when you get blowing rain or snow
You don't keep it out, It goes down through the unit and goes out the condensate drain on this particular unit. Each brand has their own way of dealing with this issue. Thanks for the Question.
Been looking for a good way to go through b vent. Thumbs up 👍🏼 on this one!
Thanks, it has been a lifesaver, sure makes it easier. We have also found that using an appropriate size hole saw works better to remove the stop.
It was the easiest way we could come up with and remain 2". Of course, you could always increase to 3" PVC and still use the existing flashing.
I just had a navien installed (Model NPE-150S2), and the vertical pipe looks like absolute dogshit coming out of my roof; is there some way to finish it to make it look better?
That T up top looks like it would let rain come down and into the water heater. All it's gonna take is a little wind to blow it right into the vertical pipe. Also, shouldn't the intake have a pipe with a screen in it to keep critters out?
Hi Don, The manufacturer's instructions call for a T on top. So, that is what we put there. As to the screen, there is a screen inside the unit that does that. If too much resistance is put on the intake, it will upset the heater. Thanks for the questions.
Does one have to worry about rain water drajning back through 2"?
Great job man. Very helpful video
As a plumber, I am impressed with the idea of using the reducer to act as a Stop for the b vent storm collar. Pretty slick. But out of curiosity, why didn't you just use a 3" PVC concentric vent kit? That way you could get your makeup air from outside and not worry about creating a back draft through the heat exchanger in the winter. I ask only because I like to hear how and why other plumbers do their thing.
Navien doesn't recommend using the 3" concentric vent kit. And we are after all in South Texas. Back drafting isn't really a problem here. Also Navien has a damper in the exhaust to prevent backdraft. I could have simply transitioned to 3" withing 1' of the top of the heater, but I wanted to do the video on this job. My supplier of Navien asked me why I didn't do that & My answer was that in this instance, it would have been fine, but on a long run, the 2" pipe & fittings are a whole lot cheaper. And just as a final note, if I had gone with the 3" concentric, I would have had to wait for it to come in. They are scarce as hen's teeth in our area. Thanks for the questions.
@@adventuresofthatplumberdud9326 im venting a couple of Naviens tomorrow. I have the concentric kit coming tomorrow. It appears you're using regular schedule 40 PVC, I see their manual says that's permissible but then they go onto list a bunch of brands approved for use with their units. It's a little confusing. Are you just using clear PVC cement and making sure the line has proper fall back to the heater if you run horizontal?
I need to do the same thing for a condensing Navien NPE-240A2, but my existing B-vent runs from the garage, through the second story wall, and out the roof. The B-vent is a straight run, but I probably can't easily remove it. Can I leave it in place and use it as a chase-way to feed approx 20 ft CPVC pipe down from the roof to connect to the Tankless WH? Is the CPVC pipe likely to rattle around inside the B-vent? The CPVC pipe could be secured/supported at the tankless WH, the garage ceiling, in the attic, and at the roof. Is that enough to pass an inspection, or do I also need to open drywall in the second story to add a support? Should I stick with 2" CPVC pipe so the volume of hot gas gets pushed out the stack before it cools and CO descends back down the pipe and into the garage? Or is this approx 20 ft length better served with 3" pipe for less resistance? Does CPVC need to be allowed to expand lengthwise like the old B-vent?
Sorry for the slow reply, The pipe that comes off of a Navien is 2" PVC, and it is possible to do what you are asking, but it will be a tight fit. 2" PVC will barely fit inside 3" B Vent.
Nice video, good tips...but please fix your camera focus! Don't you need a 90 elbow on the sides of the roof "T" so rain is not blown in?
No, there is a condensate drain on these units that also serves to take any water that comes in the vent away.
My inspector said prove that you can take the intake air from the attic. Seems obvious that a 1300 sq ft house with a 2x8 roof and 2 1x3 vents are each end would easily provide the intake air for a 2 in intake pipe. Can you help with some calculations.
Sorry for the slow reply, I just noticed there were comments that were unanswered. I would ask him to show me where in the code it says I can't. I can tell you that on a Navien, the manual says you can, provided there is adequate ventilation. Good Luck.
Wouldn't reducing the Exhaust make the unit Turn off because its not extracting enough Heat causing unit to go in to safe mode?
We didn't reduce the exhaust, please watch the video again. it is one piece of 2" Pipe from the heater all the way to the T on top. the 3"X2" reducer is an adapter to make it fit the existing roof flashing.
@@adventuresofthatplumberdud9326 i see, Original Pipe was 2" so you used 3" adapter to fit it on to the roof exhaust without having to modify! i got confused because my its a 3" from unit to roof and actually the Id its bigger than 3" something like 31/4 or so so i just added a Coupling to the pipe and it fit right in not on the outside but on the inside without even touching the existing exhaust
@quirino18 if it is a Navien Heater, that voids the warranty. The vent cannot be run in anything except PVC or CPVC pipe.
I'm planning on adapting your solution for the NPE-180S I'm installing. I'm in N. California with average rainfall and little to no snow. Couple questions:
1) How do you determine the length of pipe protruding from the roof?
Reading the comments I'm still a little unsure about the termination with regard to rain. From the Navien Installation and Operation Manual, NPE Condensing Water Heaters, v5.3 (May 29, 2019), pg. 34: "To avoid moisture and frost build-up and to maintain clearances to openings on adjacent homes, 45 degree elbows, 90 degree elbows, or tees may be attached to the end of the termination vent pipe to direct the exhaust plumes away from buildings, as long as the total allowable vent lengths, maximum number of elbows, and distances to air intake restrictions are observed."
2) Any concerns using a 90 degree elbow for the exhaust vent to keep rain from entering?
The length above the roof should be 18"-24". We always use a T on too of the vent pipe. In the off chance some rain does fo down the vent, it is directed down through the burner assy & comes out the condensate drain. I have seen them improperly installed with nothing on top & they worked just fine. The 180S by the way is the same setup as the 240A. I would however suggest that you go with an A model.
@@adventuresofthatplumberdud9326 Great, thx for the reply and the info. Nice work!
How can you use PVC for exhaust? What are the temps coming out of that? You'd think they would be pretty high, above 200F exhaust gas temp. We just got a Takagi and it says you have to use Category III.
The temperature of the exhaust coming out of this unit is around 100 degrees, that is well within the limits of PVC pipe. Your Takagi isn't a condensing unit, therefore you must use category III Stainless vent pipe. This unit reclaims 99% of the heat generated by the burner. Yours will reclaim about 70%-80% of the heat. That is just one of the many reasons we think Navien is the best heater on the market.
Thank you for the video. Is it a good idea to run the PVC pipe thru the exist Type B vent all the way up to tip of the B vent? This way no need to remove the exist B vent. Thank you
Sorry for the late reply, I had no idea that I had comments. No, it is a corrosive exhaust and would quickly deteriorate the metal vent. The manufacturer states that it must be PVC or ABS pipe.
Do you put anything on the air intake side? Like a short piece of pvc with a 90?
When we started out, we were not, just putting the grid piece that comes with the heater, but now we put a street 90 in the intake & put the grid in that. I figure that way nothing can fall into the heater.
@@adventuresofthatplumberdud9326should go to the outside
why didn't you put a plastic screen or something on the pipe you did with the original flashing?? wont squirrels and other thingks like birds try to get in there??? we have all kinds of squirrels and small birds around my area. no way i would leave those holes without screens plastic or another type screen.
If you mean the original flashing, we reused that hole and put 3" PVC Pipe through it. If you mean the outlet for the water heater, we do install a plastic screen that comes with the heater. You have to e very carful when covering these vents, if you put too much backpressure on the heater, it will stop working & throw an error code.
I have a navien combi unit , it is in my basement. Can I vent it to my roof? It is currently spitting out the side of my house. Any ideas would help greatly, thanks 🙏
Yes you can!
@@adventuresofthatplumberdud9326 are there any steps other than just running it up and out? Feel like condensation will build
can you use the 4" for intake at the same time?
Only if you purchase a Concentric vent system.
Could you run the exhaust vertically up the old water tank chimney?
no!!!
No, it is a corrosive exhaust and would quickly deteriorate the metal vent. The manufacturer states that it must be PVC or ABS pipe.
Also my installer did not use an expansion tank for my Navien 240S tankless water heater. Can this be a bad idea?
With Tankless, there is no thermal expansion, so an expansion tank is no necessary, However, your town or jurisdiction may require one, and if that is so, then he needs to add one.
why not just shove the pvc pipe into the bvent? Have a separate pipe for intake and you're done.
Because if you do that Navien will void the warranty. I had a customer that the installer did that and they did indeed void her warranty.
so the gas line that fed the original tank water heater was sufficient to supply the tankless? the tankless heaters are usually about 5 times the btu of the tank heaters
Yes sir, there was a 3/4" gas supply already there. But just for future reference, Navien heaters can run on 1/2" supply under most conditions. Thanks for your question.
My installer did not use a sanitary T at the top of the vent pipe on the roof. He used a 45 degree elbow with a plastic screen. I have a little concern about rain water entering the unit and causing damage.
He should have used a Tee, that is what the instructions call for. If water does enter the unit, it should be channeled into the condensate drain, but if it is a really hard rain, it could overwhelm the drain and cause damage to the unit. I would definitely get it changed.
Okay I’m going to change it to a tee. I noticed in your video that your tee doesn’t have bird screens. Does it not need screens?
If it is in an installation that isn't used often, such as a beach house, I would suggest screens. But this is a single family home where the heater gets used frequently.
you can get away with a 90 or two 90s pointed down (no rain) but always bid screen
Why not just adapt to the B Vent
B Vent can't be used on a condensing Tankless water heater as corrosive water condenses in the vent. Plus the Manufacturer specifies PVC pipe as the vent material.
@@adventuresofthatplumberdud9326 Gotcha. That's what I thought aswell until Noritz came out with the EZTR50 Bundle.
Has the exhaust vent tieing into the existing HWT venting.
Put a pan in
We always do. This was not a complete installation when we shot the video. Hurricane Harvey came through shortly after we installed this heater and had no leaks from that.
You can't vent straight into the old one like that it has to penetrate all the way. The moisture will build up and come back in the house.
I am not sure what you are saying here. We didn't use the old vent at all, just the roof jack. Been doing it this way for about 5 years with no issues whatsoever.
Pretty sure Navien requires a candy cane for the top of the venting for their warranty.
They do not - that's the intake never the exhaust
Navien requires a T on their exhaust, If you go above the roof with the intake, it requires a candy cane. If you take combustion air from the attic as we do in Texas, you can just put a 90 on top of the heater.
Terrible plumbers give us HVAC guys bad rep that was awful install and need to follow venting in navien installation manual at least new flashing for pvc venting and you are supposed be using cvpc schedule 80 on exhaust and supposed use an intake for combustion air what are you guys chuck in a truck would not be proud. Of that install terrible hack city
Well Brian, it is very obvious to me that you are not at all familiar with Navien Water Heaters. They do not require schedule 80 CPVC pipe for their vent, in fact, schedule 80 CPVC won't even fit the vent collar on top of the unit. So, maybe you should stick to doing HVAC and leave the plumbing to the professionals.
Great video it is exactly what i needed to know, as i am replacing a 40 gallon tank heater with a Rinnai RX 180 IN condensing unit it is an indoor/outdoor convertible model. If you are familiar with that model, will you procedure as stated in your video work for me. It will be installed in an exterior water heater closet with a vented door but i want to run the exhaust through the roof flashing as you did in the video, the the roof existing roof vevt is very shirt only about 4 feet from top of old tank to top of old termination cap on roof. Thank you so very much. Greg