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Rick
Rick , General Contractor
Category: Home Improvement
Satisfied Customers: 18713
Experience:  Licensed construction supervisor with 35+ yrs. experience.
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why is my natural gas wall heater pumping hot air out of the

Resolved Question:

why is my natural gas wall heater pumping hot air out of the top vent when the entire system is off?
Submitted: 3 years ago.
Category: Home Improvement
Expert:  Rick replied 3 years ago.

Rick :

Welcome, my name is XXXXX XXXXX I will do my best to help you with your issue.

I need the brand and model of your unit

Customer:

The furnace does not have any identification tags. It is an old style natural gas wall heater with the pilot light on the bottom. It has a grate at the top with a fan and vent opening that is pumping hot air into the room, even when the furnace is turned off (pilot light running)

Rick :

The pilot will put out a little heat but the main burner has to be running for it to generate any significant heat.

Customer:

Where is the main burner and why would it be working if the furnace is off?

Rick :

The main burner is inside the unit. The pilot lights the main burner. If the main is running you probably have a short in the control wiring

Rick :

If the main was running you wouldn't be able to touch the unit since it would be too hot

Rick :

what is the top vent you refer to?

Rick :

the flue?

Customer:

there are three vents (grates) - one for the pilot light and there is one above it. These do not open. The top vent is larger and opens. It has a large fan and an opening that I believe goes to the vent pipe in the roof.

Rick :

Ok so it's still connected to the exhaust vent/flue. So if you're getting a lot of heat out of this you need to have it serviced. In the mean time you can just turn of the gas to it (it should have its own shut off) if it's too hot

Rick :

sorry for the typo, it should say>turn OFF the gas

Customer:

could the heat be caused by an obstruction in the piping that goes to the flue vent in the roof

Rick :

not if it's turned off

Rick :

The heater will only get significantly hot if the main burner runs. Since I'm not there I can't know how hot it's getting. Like I said the pilot puts out a little heat.

Customer:

Thanks for your help. Have a nice evening

Rick :

even if the exhaust vent is blocked it won't affect the pilot

Rick :

You're welcome!

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