# Tankless water heater vent material question.



## snyper1982 (May 18, 2015)

Our shop has come across a weird issue. We have to change out a tankless heater, from a non condensing unit, to a condensing unit. I would think we could use the higher quality metal non condensing vent for the condensing unit as well, but unsure. Have any-of you come across this?


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## plumbdrum (Nov 30, 2013)

What's the manufactures instructions list for materials? Whatever it is ( more than likely plastic) you follow the instructions.


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## sierra2000 (Sep 19, 2011)

PVC.. Should say in the installation manual.


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## Ghostmaker (Jan 12, 2013)

Just a mention the PVC pipe manufactures do not allow it to be used as a flue. So if it fails it's on you and the manufacturer.


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## bct p&h (Jan 19, 2013)

Ghostmaker said:


> Just a mention the PVC pipe manufactures do not allow it to be used as a flue. So if it fails it's on you and the manufacturer.


One manufacturer does. I think it was IPC? You know that screened 90 that comes with power vented water heaters? They make it and they say it can be used for flues.


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## paultheplumber1 (May 1, 2014)

Some local code enforment officials will not allow me to use pvc. Does not matter what man specs say. Most of the time CPVC is allowed or in one jurisdiction we have to use a duravent material. This seems to be a highly controversial topic on here.


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## plumbdrum (Nov 30, 2013)

paultheplumber1 said:


> Some local code enforment officials will not allow me to use pvc. Does not matter what man specs say. Most of the time CPVC is allowed or in one jurisdiction we have to use a duravent material. This seems to be a highly controversial topic on here.



Unless the city, town or state puts in a ordinance or modification to their adopted gas code , you follow the manufactures instructions. Just because a inspector has an opinion he can't just make up a code. Tell him to show you where to find this code. I think your in RI and I know it's a topic out there and I've asked a plumber where it is written he doesn't know just that's what the inspector wants.


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## mccmech (Jul 6, 2011)

plumbdrum said:


> Unless the city, town or state puts in a ordinance or modification to their adopted gas code , you follow the manufactures instructions. Just because a inspector has an opinion he can't just make up a code. Tell him to show you where to find this code. I think your in RI and I know it's a topic out there and I've asked a plumber where it is written he doesn't know just that's what the inspector wants.


Thank you, sir, for posting this!!!!! So many plumbers quake when the mere name of an inspector is mentioned. I have always been of the mindset that the inspector is an enforcer of existing code. They do not have the autonomy to implement their own, without some documented proof from the local jurisdiction. It is very reassuring, to me personally, to hear one of "you" guys acknowledge what their responsibility is. Thanks again, sir.


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## plumbdrum (Nov 30, 2013)

mccmech said:


> Thank you, sir, for posting this!!!!! So many plumbers quake when the mere name of an inspector is mentioned. I have always been of the mindset that the inspector is an enforcer of existing code. They do not have the autonomy to implement their own, without some documented proof from the local jurisdiction. It is very reassuring, to me personally, to hear one of "you" guys acknowledge what their responsibility is. Thanks again, sir.




Why thank you, I always stay between the covers of my code


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## Dpeckplb (Sep 20, 2013)

Up here is system 636 PVC, or metal direct vent.


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## bct p&h (Jan 19, 2013)

mccmech said:


> Thank you, sir, for posting this!!!!! So many plumbers quake when the mere name of an inspector is mentioned. I have always been of the mindset that the inspector is an enforcer of existing code. They do not have the autonomy to implement their own, without some documented proof from the local jurisdiction. It is very reassuring, to me personally, to hear one of "you" guys acknowledge what their responsibility is. Thanks again, sir.


Inspectors are only supposed to enforce code, not write it or interpret it. We all know all Inspectors have one thing or another that they enforce more than others but it shouldn't be anything that isn't in the book.


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## paultheplumber1 (May 1, 2014)

Sometimes it's not worth arguing. I would press the issue if it was an isolated incident but it's becoming more and more of a theme at least around here. Even the supply house guys are pushing the use of CPVC vs the PVC for flue gas appliances. As a matter of fact the Crown Phantom series of condesing boilers come factory with a manditory 3' piece of CPVC for the vent before you convert to regular PVC.


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