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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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
504 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
748 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
7k 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
250 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
612 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
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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1answer
3k 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
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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2answers
485 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
35 views

What is required for seasonal maintenace of a heat pump?

Over the years I've had several local HVAC companies provide seasonal maintenance of the heat pumps and propane furnace in my house. It seems that every technician--even within the same company--does ...
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1answer
68 views

How can I improve the directional flow of my furnace exhaust pipe?

This one's for the creative folks. I'm in a condo on the top floor and I have a side neighbor. Both our furnaces exhaust out the back, under a four-foot roof section overhang (sticks out about a foot ...
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2answers
10k views

How far should my wall be from my furnace/water heater?

) we are refinishing the basement and are enclosing the furnace/water heater, leaving a thin 27" door. My water heater sits back beside my furnace and the enclosure is going to be square so I think ...
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2answers
1k views

Where's the C terminal on my boiler control?

The new thermostat I purchased doesn't run on batteries, and needs 24 volt power. I have only a red and a white wire connected between the boiler and the thermostat, but there is also a third, unused ...
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1answer
467 views

What could cause the furnace blower to come on constantly and no fire in gas burner?

When thermostat is turned up on my hot air furnace, the blower immediately comes on, blowing no heat, had it checked and with some luck the burner fired after about 10 tries of switching on and off. ...
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1answer
2k views

how to change furnace filter (bottom return) for Lennox G43UF

I have a Lennox G43UF furnace and I am not sure if I need to have both a filter for a side return and bottom return. If I do (which sounds logical), where would the location of the bottom return ...
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1answer
552 views

Could a high limit switch cause the furnace blower to run continuously?

My furnace was running fine. The I noticed that the unit was blowing cold air. Checked the furnace burners and they were off. I turned off the unit on the thermostat and the blower continued to run. ...
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1answer
371 views

Will a single ductless mini-split heat pump be able to distribute its air evenly throughout my ranch house?

I am in the middle of a deep energy retrofit of my house, and a quick-and-dirty online manual J calculation of the projected loads once my projects are completed shows an estimated heating and cooling ...
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1answer
791 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
3k views

Why is the circuit breaker for my furnace stuck in the off position?

The breaker for my furnace is stuck in the off position. We were away for the winter and had someone shut it off, and now the breaker won't turn on at all. We shut off the thermostat upstairs thinking ...
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1answer
203 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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2answers
877 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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5answers
22k 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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1answer
1k 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
20 views

Furnace fan starts slow and is getting slower

here is a sound clip, start at about :55 or listen to whole thing! https://clyp.it/3h54oe2q model is tg9s060b12mp11 luxaire, which comes up as York most places. Anyhow, what's the best way to ...
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0answers
283 views

How can I reduce noise from an air handler unit in an open closet?

How can I reduce the noise from an air handler unit? I have a Goodman AR42-1 air handler unit in an open closet. The setup looks like this: When the air handler activates it sounds like this: ...
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1answer
44 views

Can't get fan working on thermostat

I recently purchased a new thermostat. My old thermostat worked for heat (no AC either) but the fan wouldn't go on when I turned to "On" (in hopes to move some cool air from the basement up during the ...
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1answer
936 views

my furnace fan stays on even when at temperature

I recently installed a 2nd generation NEST thermostat. I'm not home very often, but I was paying particularly close attention to the furnace after installing this thermostat and I noticed that the ...
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0answers
50 views

Why would my Maytag FG6RC high efficiency furnace restart in the middle of a heating cycle?

My furnace is probably 7-8 years old, and this heating season the furnace has developed a strange problem. The furnace starts normally, but before the temperature reaches the thermostat setting the ...
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2answers
709 views

What could be causing my furnace burners to fire up, then shut off due to partially open door?

I have a 10 year old Carrier gas furnace that keeps shutting off every 24-48 hrs. First I thought it might be the flare sensor but then I checked the bottom door and it wasn't completely closed. I ...
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1answer
279 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
490 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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0answers
295 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
225 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
39 views

Can I replace my furnace's high limit switch with a comparable third-party part?

I have an older Lennox furnace. The high limit switch (#60T15,130F) has gone bad. I haven't been able to find on-line this part number with the exact temp limit specs, and Lennox no longer carries ...
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5answers
568 views

Low voltage fuse blowing in furnace

I have an outside A/C compressor and indoor furnace fan combo in the attic. The unit was off and the 3 amp fuse was blown. I replaced the fuse and used the thermostat to turn the fan on followed by ...
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2answers
10k 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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3answers
2k 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
791 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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3answers
40 views

Sealing gas duct vents with silicone

Is it okay to use silicone to seal gas furnace heater supply ducts? If so, do you know how long the silicone will need to cure before the system is useable? Some background: I've been trawling around ...
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2answers
55 views

Do natural gas furnaces have internal breakers?

I rent a house with a natural gas furnace. The furnace was not working at the beginning of this winter, and so we called the landlord to fix it. The landlord hired a repair man, who came and noticed ...
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4answers
2k 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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2answers
200 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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3answers
61 views

Will a high efficiency furnace vent etch the brick on my house?

My neighbour just informed me that they had to change the vent on their high efficiency furnace. The furnace vents between our two houses and it used to have an elbow on it directing it along the ...
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2answers
72 views

Very old furnace- I need a technician to inspect it-What would be a good check up list?

First of all you should know that this is about a 25 years furnace that is very simple and that if nothing is wrong with the heat exchanger it should last forever since, IMHO, the parts are very ...
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2answers
318 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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2answers
5k 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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2answers
32 views

Condensation on cold air intake

Our home is relatively new (built in 2014), but something I noticed is that the PVC pipe going into our furnace (which connects to the outside of the home) is developing some condensation (which can ...
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1answer
49 views

Can using a new evap coil on top of an older furnace cause problems?

I am getting quotes for a new R410A condenser unit/evaporator coil from several HVAC contractors. A salesperson refused to give me a quote unless I purchase a new furnace as well. He said that he has ...
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1answer
39 views

What and how many appliance can share a room?

Can a central air gas furnace, gas dryer, electric washing machine, gas water heater be in same room (12x8ft) in the basement? dryer has its own vent to outside, Gas water heater, seems to use the ...