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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Do I need a rain\snow cover on this furnace vent?

Just bought a house that had a new furnace installed this summer. Vent number 1 in the image is for the furnace (2 is the water heater and 3 is sump). As you can see in the image, 2 and 3 both would ...
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331 views

Can I manually run the blower on my Lennox G12Q3 furnace?

I have a Lennox G12Q3-120-6 model furnace. Does anyone know if there's a way to manually run just the blower without heat? There are no switches on the outside that I can see (other than the power ...
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1answer
281 views

Is it normal for air to be leaking from where the drain hose connects to the central A/C unit?

I'm trying to determine if I have a leak around my central AC unit. Basically when the unit is on, I feel cool air blowing outside the "furnace plenum" as I believe its called. If you look at this ...
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2answers
543 views

What could be wrong with my furnace?

The furnace started blowing cold air so I checked the furnace and the burners weren't lit only the pilot was on. This happened last year and repairman said that if it got too hot would trip a sensor ...
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2answers
879 views

Is there a filter-reminder thermostat that uses run-time instead of total time?

My HVAC filter is in my crawlspace and is a hassle to change. I don't want to change it more than needed. "Change it every month" is bogus advice because in some months (like May) we don't have to run ...
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1answer
568 views

Why won't the heat shut off in one zone?

we have a three zone baseboard hotwater furnace. a few months ago one zone would randomly stay on, we did change the thermostat we have not noticed the problem again, but in another zone we have the ...
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1answer
216 views

Can I reduce the size of my hot water heater vent or direct the vent out the exterior (house has high efficiency furnace)?

The shower in my master bath is tiny. When I removed some dry wall to see if I could widen it, I found a large ~10" round vent running through the space(must be the furnace). Now that I have a high ...
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1answer
432 views

How well would a hydronic furnace work with a gas tankless water heater?

My current heating system (in Ontario) is an oil hot water tank in a closed loop with a hydronic forced-air furnace (Enerzone XAH 68). The water circulates through what is basically a heat exchanger ...
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4answers
1k views

Why do I have two parallel gas pipes?

I've got a water heater and a hot water radiator furnace sitting next to each other, both on gas. The strange thing is that there are two parallel gas lines feeding each one of these which come from ...
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1answer
178 views

Is there a standard length on the PVC furnace pipes coming outside the exterior?

We have a high-efficiency furnace. Two pipes are coming outside the house as expected. However, right now, there is at least 2 feet or more of extra PVC on the exterior showing. Is there any ...
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2answers
2k views

How do I troubleshoot an electric furnace?

I have a Coleman 3300-9051 electric furnace w/AC. The blower continually runs. Where do I find a repair manual and/or what could be the problem. How do I test it.
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1answer
251 views

Is it safe to put a gas furnace in the same room as an electric clothes dryer? [duplicate]

Possible Duplicate: Can an electric dryer be next to the gas furnace? We are currently remodeling our house. Is it safe to put a gas furnace in the same room with an electric clothes dryer? ...
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2answers
365 views

Is there a way to find out how often your furnace is running?

With winter finally setting in, and being the first year in our new house I would like to put some sort of measurement on how often the furnace is working, before I get the bill. Are there any known ...
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2answers
764 views

Can an electric dryer be next to the gas furnace?

I intend to relocate my washing machine and electric dryer within the basement. The dryer will then be about 2 feet from the furnace. Is that OK?
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4answers
4k views

Can I connect an outdoor wood stove to my current HVAC system?

How to install a wood stove as an auxiliary heat source? (Main is electric furnace with forced air) I've read this question, it doesn't really answer what I need to know. What I would like to do is ...
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0answers
211 views

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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0answers
239 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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0answers
204 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
1k 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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2answers
664 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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1answer
178 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
194 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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1answer
462 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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5answers
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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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2answers
158 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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1answer
7k views

How do I test a furnace limit switch?

When my thermostat reaches the desired temperature, the furnace fan shuts off briefly, then cycles on and off a few times. Several internet posts pointed me to the limit switch, which seems to make ...
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1answer
692 views

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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1answer
2k views

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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2answers
3k 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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5answers
2k 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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2answers
201 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
267 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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3answers
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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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3answers
11k 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
706 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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3answers
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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2answers
175 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?