Power Vented Hot Water Tank Back drafting Cold Air

[roblouvasz]

Just as it says, the power vent draws from the basement air when running but cold air backdrafts when it's not running. Anything I can do to prevent it? One way flapper valve?

 

[Jackfre]

You have to follow the directions of the manuf. There is no better option.

 

[ripperd]

The only reason why air would be coming in, is if it had a different place to escape.

Where is the incoming air escaping to? Fix that, and you won't have much coming in any more.

 

[Showkey]

Just as it says, the power vent draws from the basement air when running but cold air backdrafts when it's not running. Anything I can do to prevent it? One way flapper valve?

What other devices are looking for “make up air” or creating a negative pressure in the home ???? Like an 80% furnace with inside air draw ? Or even a 90plus furnace with no outside air intake or a large cook top fan on high or fireplace in use ????

A strong prevailing wind will create some cold air but it should not be a consistent or constant flow. Is the termination an open pipe with no down turn ?

 

[mobetta]

Depending on the home, all the holes made to run the mechanical system through a house cause enough drafts from stack effect. older homes no care was given at all. Like HVAC guys and plumbers with chainsaws!!
New code requires sealing.

Make sure all penetrations are sealed in the mech room ceiling and any other that you can access. can foam, tuck tape, decent Caulk

 

[Jim greengo]

Put a 90 on the end of it.

 

[TTTTTT]

Not quite right there . A power vented hot water heater /tank does not draw air from the basement when it runs. It only exhausts the exhaust from the combustion of either NG or propane. It eliminate s the need for a chimney that would naturally be exhausted. A high efficiency furnace does either draw from the basement or draw from the outside if piped that way

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[Bert_]

Not quite right there . A power vented hot water heater /tank does not draw air from the basement when it runs. It only exhausts the exhaust from the combustion of either NG or propane. It eliminate s the need for a chimney that would naturally be exhausted. A high efficiency furnace does either draw from the basement or draw from the outside if piped that way

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Why don't you enlighten us all as to where that air comes from then...

 

[Bills Tools]

The makeup air for combustion on most power vented water heaters is drawn from basement. Air has to get into burner section for combustion. The down draft is why my power vented 75 gallon water heater runs non stop. The tank leaked back i April and I soldered it shut. Now I noticed it is leaking again. Instead of buying another power vented water heater, I bought a 50 gallon indirect water heater. No burners and very little heat lose. Plus first hour it can produce 200 gallons of hot water compared to the 75 gallon only producing 100.


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[Showkey]

This thread has left the rails.............train wreck

 

[WisJim]

Not quite right there . A power vented hot water heater /tank does not draw air from the basement when it runs. It only exhausts the exhaust from the combustion of either NG or propane. It eliminate s the need for a chimney that would naturally be exhausted. A high efficiency furnace does either draw from the basement or draw from the outside if piped that way

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Not always true. Every power vented water heater I have seen draws combustion gases from the burner which gets combustion air from the basement, they typically don't have directly supplied outside air for combustion. The OP's problem may be due to bathroom fans, range hoods, and/or other other exhaust fans running, or natural venting elsewhere in the building structure which finds the water heater exhaust as the best source of incoming makeup air. This problem sometimes occurs because of kitchen range hoods that should have dedicated makeup air supplied to them.