Gas Heater Substitution

Old 07-09-10, 06:34 AM
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Gas Heater Substitution

I currently have a forced exhaust propane fired water heater. It has a blower fan that forces exhaust air into a 3 inch PVC pipe that runs about 4 feet up and 1 1/2 feet horizontal to the outside of the house.

When this thing quits, would it be possible to replace it with a standard naturally vented water heater or isn't there enough draft in the current exhaust pipe system as described. Also, would there be too much heat in the exhaust gases for the PVC to handle.

A new standard gas heater is about $400 vs. $1300 - $1500 for a blown heater.

Old 07-09-10, 01:14 PM
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You can't run a standard water heater through a pvc power vent exhaust. Depending on the code where you live you may have to run the exhaust through the roof and not the side of the house, sorry.
Old 07-09-10, 03:50 PM
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Another option might be an electric heat pump water heater & a cheap electric heater for a tank. Google "airtap" to see what I'm talking about. Not as expensive as replacing what you have, and cheaper to run as a side benefit. It only needs a 110 outlet to run.
Old 07-09-10, 04:00 PM
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A natural draft water heater requires metal vent pipe and must be vented through the roof. The natural draft doesn't develop enough force to vent the combustion gasses out a wall vent. The exhaust gasses would simply spill into the dwelling space through the draft diverter on top of the water heater.

A power vented water heater can use plastic pipe because quite a bit of room air is used to dilute the hot combustion gasses enough to use plastic. Of course, every cubic foot of excess air must be replaced by a cubic foot of cold air infiltrating the house, and generally that excess air must be heated or cooled to the room temperature.

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