The furnace is part of an HVAC or central heating system used to generate heat. Typically this is done with gas, a heat pump, or an electric element. For hot water and radiator based heating, use the boiler tag.

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How can I clean out the pressure switch port at the inducer housing on a Lennox G40UH furnace?

I have a Lennox G40UH(x) furnace, but the gas does not ignite, because water may have entered the system while raining, or the the pressure switch port at the inducer housing has just to be cleaned. ...
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268 views

Why won't my condenser turn on when I run my heat pump?

I have a York Affinity condenser. When I run my heat pump, I expect it to turn on somewhere in the cycle but it doesn't. It generally does this once a year. The usual fix is to cycle the power of the ...
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212 views

How do I know if my high limit and low limit are set correctly on my aquastat?

I have a boiler that is only providing heat for my forced hot water baseboard system (4 zones). I've always thought that the high limit on the aquastat was too low (the temperature on the boiler ...
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2answers
2k views

Is it OK to turn off power to a fuel furnace?

Is it OK to turn off the power to a fuel furnace to replace the thermostat? Will the furnace start back up once power is restored? This is on a new furnace with an old thermostat and fuse panel.
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889 views

furnace creating a ground?

our gas furnace has a junction box on the side of it for the 110 feed for the blower, the feed has no ground wire , if i put a meter on the hot wire and metal box i get 110/120 , without a ground wire ...
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181 views

Are discount furnaces safe to use?

More newbie questions ;-) The house we're looking to buy has an older furnace that "may be manufactured by the Permier/Consolidated furnace company" according to general inspections. We're in the ...
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1answer
201 views

Where can I find resources on Gas Furnace manufacturers

We are going to replace a 30 year old residential gas furnace. We have estimates for furnaces from Rheem, Trane and Bryant. This is a rental, so we aren't going for the 95% with tax rebate but ...
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528 views

Furnace Airflow

I have central air. When the furnace comes on, we can feel air coming out of the registers for a few minutes, then the airflow stops. If we turn it off for a few hours, we can turn it on again and get ...
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How do I prevent ice stalagmites from building up on the furnace exhaust?

I have a high efficiency furnace that exhausts via a pvc pipe out the side of the house, the trouble is the moisture from the exhaust forms an ice stalagmite in my driveway in the cold weather. Are ...
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166 views

What to do about furnace that's drawing gas odors into the room instead of heat?

I have a gas furnace. It was heating up the place fine and worked for years until the other day. All of a sudden it started drawing air that smelled like strong gas odors into the room rather than ...
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Insulating ducts in a crawlspace

Consider a source duct from the furnace/AC. The ducts run in a vented crawlspace. The floors atop the crawlspace are a mix of hardwood and kitchen vinyl. The symptoms are: the longer run vents ...
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How do I fix a condensate drain line that froze in my split electric system with heat pump?

I have a split electric system with a heat pump. It looks like my condensate drain line is frozen. I switched to supplemental heat which does not use the heat pump. Is this enough for now? Our ...
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4k views

How can I tell what kind of heating system I have?

Seems like a simple question, but I've had a very hard time finding a definitive answer to this. I went to the hardware store to buy a replacement for a faulty thermostat and when I arrived and ...
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3k views

How often should the air filter in the furnace be changed?

Does the period of change of this air filter have an affect on the longevity of the heating and a/c system? What is a good rule of thumb to require replacement?
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225 views

Oil-fired furnace sight window repair

I have an 20+ year old oil burner and a tankless boiler/furnace. There is a small round (2-3" diameter) window above the burner that lets you see the flame, I assume as an aid to tuning the burner. ...
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1answer
283 views

Massive reduction in air flow in furnance with air filters

After I put in a 3M filter into my furnace the air flow was massively reduced. So, does that mean the filter is wrong or something is wrong with my furnace.
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Why is my furnace blowing cold air?

My HEIL 7000 natural gas furnace has stopped working what are the most likely causes, and how to verify faulty parts? Normal operation routine Thermostat sends "need heat" signal. Exhaust blower ...
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16k views

Why do our baseboard heating pipes make a loud banging noise after a new furnace was installed?

We had a new furnace installed about a month ago. The heating in our house is hot water baseboards. Ever since the new furnace was installed, when the heat comes on or turns off, there is a loud ...
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1answer
866 views

Why does my gravity vented wall Furnace keep turning off/

We have an Empire gravity vented wall furnace: That turns off. According to the instructions, this is because the vent safety switch. But when I open up the furnace, it appears to be vented just ...
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2answers
1k views

Does it matter where my furnace condensate pump gets power from?

The existing condensate pump for my furnace recently died. It was hard-wired directly into the electrical panel of the furnace but I was able to disconnect it. However, when looking for a new pump, ...
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1k views

Can I close the garage vent on my furnace?

My furnace duct system has a vent in the garage, right over the furnace. Is it necessary for the proper operation of the furnace to keep that open? I'd hate to waste the money heating up my garage, ...
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188 views

How do I choose a furnace airfilter?

I have a furnace/air-conditioner that can support filters of various thicknesses: 1", 2", or 4". Filters are available in various MERV ratings. How should I decide which filter to use?