# IPC 502.2 chapter 5 water heater - rooms used as a plenum.



## Garyp (Jul 14, 2017)

states : water heaters installed using solid, liquid, or gas fuel shall not be installed in a room containing air-handling machinery where such room is used as a plenum. 
Does this mean that you just cant install a water heater in a room with an air-handler at all when the room is used as a plenum to fire the water heater, or does it mean not to install a gas water heater with an air handler in a room where the room is used as a plenum when the air handler uses a non ducted return? someone please explain this to me.


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## Debo22 (Feb 15, 2015)

Here's a link explaining that

http://www.plumbingzone.com/f3/why-post-intro-11368/


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## GAN (Jul 10, 2012)

Where the room itself is "the open plenum", the negative air pressure may caused CO to be drawn back into the air handler causing CO poisoning.


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