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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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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1answer
413 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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1answer
191 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
617 views

How can I stop my house from waking my wife up every day in the winter?

I'd like to preface this post with the fact that I'm a complete diy amateur. I may say stupid things, or things that make no sense. Please feel free to correct me as I'm always open to learn. So, ...
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3answers
1k views

Does a whole house humidifier go on the intake or outlet of the furnace?

On what side of the furnace do I install the tank of the humidifier (the warm side or the return air side)?
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237 views

Furnace flashing 4 times (Ducane)

My Ducane furnace flashes 4 times, runs for 5 minutes, and then the burner goes off. When the limit switch is jumped it runs good. What needs to be changed here?
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1answer
2k views

Why does my pilot light go out when I release the pilot light knob?

My furnace pilot light will not stay lit. I can light it and depress the pilot switch for 2 minutes. But, once I let go of the button, the pilot immediately goes out. Does my thermocouple need ...
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2answers
936 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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2answers
168 views

Should my furnace closet have this huge duct opening into the unconditioned vented attic?

So my interior furnace closet has a huge duct in it that connects the closet to the unconditioned vented attic right above it. Needless to say, this is a huge air leak into the conditioned part of the ...
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2answers
3k views

How do I identify the C terminal on my HVAC?

How do I identify the C terminal on an HVAC, furnace, or boiler? If the terminals don't have a screw labeled C what should I look for on the wiring diagram? What steps should I take if a wiring ...
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2answers
7k views

How do I wire an old furnace motor so I can use it as a garage exhaust fan?

Since last I posted, I moved WAY south (lil warm down here) and the house I moved into was a foreclosure so a few things needed done, namely the AC and furnace. When the guy did the job he said he ...
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2answers
19k views

Why does my pilot light keep going out?

My furnace pilot light keeps going out so I changed the thermalcoupler now the furnace will come on and heat up to the degree set on my thermostat, then the pilot goes out and the furnace will not ...
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2answers
4k views

Is my furnace operating normally?

I just moved into my house and I am wondering if this is normal for a furnace. So I have my furnace set to 68 degrees. The temperature on the thermostat says 66 degrees. The furnace is on, but does ...
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1answer
61 views

Can I properly install Roxul mineral wool batts in a mostly-drywalled stud bay by pushing them up from below?

Using my nifty thermal camera, I discovered that my furnace closet's combustion air duct (visible in this question) is getting really hot when the attic heats up, and then (being sheet metal) it ...
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2answers
100 views

What could be causing my gas furnace to make a loud noise?

I have a comfort air natural gas furnace when it call for heat,their is a loud boom noise,could the hot surface ignitor have a crack or needs replacing?
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2answers
90 views

How do I make my gas furnace throw out warmer air?

I just bought a new house. It has a 2007 gas furnace. The make is a 2007 heil furnace . I would like to know how to adjust the furnace to make it throw warmer air out of the ducts.
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2answers
853 views

Can I remove the fresh air supply that is attached next to my furnace?

It looks like my gas furnace is already vented but I'm not sure. There are two white pipes from the top of the furnace that are vented outside. The furnace is a Trane XR90. We have cold winter climate ...
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1answer
184 views

What is a quieter alternative to gas forced air heating?

My small 1BR apartment has an old gas furnace that works great, but costs my landlord too much to insure. He plans to install gas forced air, an in-unit upright furnace. I'd love to suggest a ...
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2answers
340 views

Can I move my furnace room ventilation intake closer to my furnace?

I live in a 3 story townhouse with a garage in the basement. Off the side of the garage is our furnace room. The ventilation and exhaust for the furnace goes to the roof. For ventilation (air coming ...
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1answer
173 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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1answer
299 views

Will I see any performance gains if I reconfigure my thermostat to control the second stage of my 2 stage furnace?

Our furnace is a two stage one that was installed last year (a Bryant 80t). When it was installed, it was installed with a thermostat for a one stage furnace. This appears to be because this model ...
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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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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
363 views

Are High End Furnace Filters worth the cost?

There are many levels of furnace filters. I can get cheap ones at walmart of a few bucks. Then there are ones that cost upwards of $30. I realize that if you have allergies or low immune systems, ...
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1answer
47 views

Is the furnace undersized?

I have a 2700 sq ft rambler home with cathedral ceilings over a large portion of it - over the hallway, 2 living rooms and kitchen. We replaced the furnace that was installed when the home was built ...
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1answer
93 views

Can a non-expandable filter be used in place of an EZ flex furnace filter?

My Carrier furnace has the EZ flex filters (16x25x5). These come with the plastic end caps that fit on the expandable filters. Can a regular filter, non expandable, of the same dimensions be used as ...
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1answer
2k views

Why won't my Heil 7000 natural gas furnace ignite?

I have a Heil 7000 gas furnace Model: NUGK100DH12 Serial: L933050100 When we turn it on at the thermostat, the exhaust blower will kick on. We checked to be sure the gas is reaching the unit and ...
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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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1answer
698 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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1answer
78 views

Is my Heat pump and gas furnace installation incorrect?

I moved into a house about 2.5 years ago, and the previous owners had a heat pump installed, together with a gas furnace. Recently I had my furnace repaired (faulty igniter) and the HVAC technician ...
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0answers
200 views

Are w1 and w2 both energized during a second stage heat call from the thermostat?

Short version: does two-stage thermostat always close W1 circuit when it closes W2 circuit, or they might be closed independently? Long version: I have two-stage furnace, currently connected to older ...
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1answer
389 views

Furnace Draft Inducer Repair: is previously installed back plate necessary?

I'm replacing a non-functioning draft inducer on the Goodman furnace in my house (GMP075-3). The previous inducer was mounted with a sheet metal back plate between it and the wall of the furnace. ...
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0answers
236 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
201 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
3k views

How do I build a firewall around my furnace/water heater?

I'm in the planning stage of finishing my basement. I'd like to section off the furnace and water heater, and am assuming that I should fireproof that section of the build. What's the best way to go ...
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2answers
805 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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2answers
528 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
169 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?
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2answers
649 views

Why is my furnace blower coming on so early in the ignition process?

Alright, I installed a new furnace a few months ago and have begun to notice an issue with the blowers. When the furnace first starts up, the exhaust blower should turn on to expel gas, then the ...
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4answers
821 views

Are 5" thick filters for furnace/Central AC still available?

My furnace/AC was installed about three years ago. It uses 16" X 25" X 5" filters. The problem is when I try to find a replacement at my local home center: at Lowe's, Home Depot, (you name it), I ...
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1answer
133 views

Which way does the air flow through my furnace?

Below is my furnace and I need to change the filter however I am unsure which way is the airflow direction. Red or Blue?
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1answer
206 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
246 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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3answers
8k views

Why is my Lennox g40uh series furnace not turning on?

I have a Lennox g40uh series furnace and it just stopped working today. I can reset the furnace and can see that on the control board both LEDs (green and red) are blinking together which indicates ...
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2answers
58 views

How can I safely put a plug on an old furnace motor that has just two wires

My Old furnace motor has just 2 wires, Black and white. How can I safely put a plug on it to use it? I want it to power a chicken plucker.
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1answer
951 views

How can I figure out why the low voltage furnace fuse blows on heat but not cool?

I have a Tempstar Model NTC6100KFG1 gas furnace. Furnace was working fine through the summer blowing the AC. It's been off for a month or two as we've been changing seasons here. When I went to turn ...
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1answer
171 views

Replacing Oil Furnace with Heat Pump

My wife and I would like to remove the older oil heat from our home and replace it with a heat pump. We currently have an Amana central air conditioning unit (3 ton), and an oil furnace in the ...
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2answers
183 views

How do I interpret my furnace clearance diagram?

My brother-in-law and I are going to be finishing my basement. We just got the permit from the building inspector. When they returned my plans there was a note that told me to make sure furnace and ...
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1answer
2k views

Why does my pilot light go out continuously?

My furnace pilot light keeps going out. The furnace will come on and heat up to the degree set on my thermostat, then the pilot goes out and the furnace will not come back on. Could the thermostat be ...
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1answer
435 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 ...