Replace direct vent water heater


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Old 12-02-07, 05:42 PM
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Replace direct vent water heater

Hello

My direct vent water heater locates in my garage is leaking. Can I replace it with a conventional stardart hood vent.

The existing water heater using 6' diameter metal vent, it run directly from the heater to the sidewall then to the outside. Total vent lenght is very short (arount 20') since the heater locates right next to the garage door.

Can I using the standart type heater by connect an 6 to 4 reducer and connect from the hoodvent to this existing 6' metal vent ????

Thank you for your help.
 
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Old 12-02-07, 05:48 PM
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In order to install a standard water heater in place of the current DV model you would need to replace all the vent pipe and vent it up beyond the roof of the garage. From where it penetrates the wall to the vent cap would need to be b vent pipe (double walled).

Additionally, if it's not already, make sure the burner of the water heater sits 18 inches off the floor since it's in a garage. This is for safety reasons in the event gasoline vapors collect on the floor of the garage.
 
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Old 12-02-07, 06:05 PM
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Thanks to the reply.

Question: What happens if I am using the existing outside hood and not "vent it up beyond the roof of the garage". Currently it is about 8 feet above ground.
 
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Old 12-02-07, 06:14 PM
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An other question about vent: Why I have to use B Type vent? Because it is the regulation or because it must have this type of vent in order to work????

The existing vent is not double wall and it made by thick metal and large diameter (6"). If I keep using this vent by adding a 6 to 4 reducer in order to connect to the water heater hood vent then what will happens???
 
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Old 02-25-08, 01:10 PM
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If you decide to use your existing vent I can think of two possibly hazardous scenarios.

1. Exhaust fumes, including Carbon Monoxide will back up into your garage and possibly into the hous.

2. Your wall will catch on fire where the vent transitions outside by not using a b vent pipe.

Either scenario could be dangerous for you or your family. I'd recommend using the correct venting for that type of heater.

-Chris
 

Last edited by AllWorkNoPlay; 02-25-08 at 01:48 PM.
  #6  
Old 02-25-08, 04:51 PM
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Another thing that comes into play with your DV Heater. The 6 inch vent is really two vents in one. The outer 6 inch pipe is for your combustion air supply and there's a inner pipe (probably 3 or 4 inches) that is the exhaust.

Do not under any circumstance use a standard atmospheric vented water heater with this set up.

It is also not recommended venting B vent up the wall on the outside because of condensation. The hot gases from the water heater will get cooled off prematurely and condensate inside the pipe causing premature rotting of the pipe and possibly the water heater.

On the positive side, with the new flare guard style water heaters, the burner is no longer required to be 18 inches off the floor (unless local code states otherwise).
 
 

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