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 do I compare furnace models?

I need a new furnace, and I have quotes from two companies, for three different brands of furnace, Carrier, Trane, and Lennox. Both companies have provided the model numbers of the units they would ...
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51 views

New Thermostat installed but compressor comes on immediately

I have a new Insteon Thermostat that I'm using to replace my prior Honeywell t-stat. This is installed to a relatively new HVAC system (both AC and Heat) that DOES have a "c" wire. I've attached the ...
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85 views

What makes a furnace pilot valve whistle?

I have a furnace that started whistling, recently. I have read that gas pressure changes can cause this. Others have remarked how seasonal gas changes can lead to a properly-adjusted furnace to ...
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107 views

My goodman furnace is not igniting my burners

I have a goodman furnace and when it is calling for heat the ignitor comes on and goes off and comes on again and the burners never comes on what could be the problem
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25 views

Central Furnace blower alwas on, even with thermostat disconected

A technician told me it was the electronic control board that has the blower relays on it , I replaced it and still has the problem, I've been reading here online about a limit switch for the blower ...
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57 views

Thermopride OL5-85 oil furnace no longer works

We bought this old house where the oil furnace worked for a while. Now it does not work even after adding enough oil and priming the furnace. We have already pushed the reset button..so I do not dare ...
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181 views

Furnace reaches temp, shuts off but wont come back on

I have an American Standard furnace (natural gas)with a manufacture date of 2004. The thing won't come on unless I power it off (have a switch right beside it that serves this purpose), let the fan ...
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34 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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62 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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77 views

What is this 6" vent coming out of the main furnace trunk going under my deck for?

I have a 6 inch round duct that comes out of the main trunk about 5 feet from the furnace. It runs through the basement and outside the house (under the deck). What is this? The furnace also has 2" ...
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27 views

Whether to replace oil furnace with oil furnace and heat pump or convert to propane

I am in need of replacing my oil furnace and central A/C. My residence is in SW Wisconsin. I am confused as to whether or not to replace with an oil furnace and heat pump or to convert to propane ...
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40 views

Should there be a cap next to my furnace ac drain?

In the picture below, the left side has a good amount of airflow while the ac/blower is running. The tube on the right is the drain that the condensation flows out of to the floor. Should there be a ...
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37 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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44 views

Is this electric furnace likely to be insulated with asbestos?

I inherited this electric furnace and I'd like to identify the material it's made from. I've not managed to find any record online, but the company itself no longer exists. Given its vintage (90s ...
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234 views

Why would a blower motor work with A/C, but burn out with furnace?

I've gone through 2 blower motors since I purchased the home 3 yrs ago. I never have an issue with the blower when the AC runs; but it keeps dying in the winter with the furnace. I've had 2 HVAC ...
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35 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 ...
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46 views

C Wire is there, now where do I connect it?

So I'm purchasing a home but the thermostat is pretty old. I'd like to replace it with a Nest or something nicer. I've searched and searched but can't find where I would connect the C-Wire (it's ...
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21 views

What could cause the blower of a Coleman furnace to come on all by itself?

I have a Coleman furnace in my mobile home. It was really hot today and the furnace blower came on all by itself. It has ran for 7 hrs. and wont shut off. How do I fix this and what is the ...
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250 views

How bad is it to attach a gas water heater to a gas furnace electrical circuit?

I'm looking to replace my existing water heater with a more efficient model. One of the things that makes better models more efficient is the replacement of the thermocouple / pilot control system ...
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224 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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36 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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131 views

Is it alright to run furnace and turn off gas?

Is running a furnace with the gas pipe shut can cause any harm to furnace?
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107 views

My A/C Unit stopped working after replacing blower motor

Any idea what I may have done wrong here or how to check? I replaced my blower motor (it was 100% compatible and had the proper capactitor), and upon starting it up the blower did nothing and the ...
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254 views

Where is my Common Wire? [duplicate]

I purchased a wifi thermostat and cannot located the common wire. My unit is old and is a Coleman 70 with no terminals inside labeling the wires. As you can see in the second image, there is a ...
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42 views

Can I add another heat run to my furnace?

I'm looking to add a bedroom to the basement and would like to add a heat run to the new room (return air will occur through an opening between the ceiling joists). This seems easy enough, but I ...
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53 views

Where should I connect the C wire in my furnace, trying to upgrade my thremostat?

I am upgrading my thermostat to a Honeywell Wifi one, and would like to add a common wire. My current furnace controller has 3 blue wires at the 24 v end of the transformer. Which of these (blue) ...
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142 views

What should I do after a low-voltage wire was cut putting the furnace door back on?

I have the basic Honeywell thermostat that a lot of people have. All the thermostat wires go to the blower in the attic (for the central air). They are spliced with wires that then go to the furnace. ...
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192 views

why does my gas furnace exhaust constantly

why does my high eff gas furnace exhaust run constantly ( when furnace isn't on ) the furnace turns on and off a few times before running then the blower comes on. now the exhaust wont stop without ...
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29 views

Gas frunace trouble shooting

Blower kicks on early and will only run 1 cycle. Have to turn down thermostat and turn it back up again to get furnace to come back on. It is gas.
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86 views

Limit switch failure

My XL80 trane failure! Limit switch SWT1258 fails at least twice a year now, first one lasted 10 years and then all replacements only last 3 to 10 months. Seems the switch is used too much but air ...
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99 views

Can I replace my draft inducer blower with a model of a slightly different speed?

My furnaces draft inducer blower sounds like a snow blower running, so I set out to replace it. Finding a replacement part proved difficult, but I found a site advertising a compatible part and ...
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24 views

Would a frozen water pump hose for a furnace make the furnace run all the time?

Water pump for furnace and the water run to outside wall, the water hose was blocked and pump motor was dead. Can this cause the furnace (fan) run all the time cost more electricity.
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819 views

Connected C-Wire to new Smart Thermostat and Furnace board and still no power

I need help. I've been surfing the internet and have had no luck finding answers to my situation so am hoping for some guidance. I've seen other questions here answered but none that suit my ...
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103 views

Why does my gas furnace run once then wont come back on until reset when temps are below 30 outside?

THE PROBLEM: My gas furnace will run one cycle and then not come back on until the switch is reset. Once the switch is reset it will kick on immediately run once and again I will have to reset before ...
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102 views

Goodman gas burner not lighting

Goodman warm air gas furnace. Gas burner would not light.Status code light blinked continuously. Igniter glows red hot. I cleaned flame sensor with fine grade sand paper. Checked transformer line ...
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226 views

how do you manually turn on the gas to your house?

During an account switch our gas got turned off. The account is straight now but national grid goes on coffee break from 12am sat till 7am monday and for us, enough is enough. 3 family 3 story ...
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39 views

Goodman GM100 Failure to recycle

Our Goodman Furnace Model GM100 Serial# 9412063230 will start up and run but will not recycle after initially satisfying the thermostat. If you wiggle the gray,(ground), wire on the gas valve, it ...
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8 views

Goodman GM100 fails to recycle [duplicate]

Our Gm 100 Furnace fails occasionally to recycle after working fot a while. I have determined that something is becoming disconnected in the black terminal "box" on the gas valve. If I move the gray ...
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630 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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80 views

Why does my furnace only heat up to a certain temperature?

Why does my furnace only heat up to a certain temperature, then it stops heating the home? My programmable thermostat is set to go up to 70 degrees (to heat the home) and for some reason when it ...
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49 views

Can a full expansion tank prevent the furnace from going on?

Woke up this morning and the furnace wasn't working. The furnace is relatively new, and there appears to be a small amount of water dripping from the top of the expansion tank. I know that the ...
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209 views

Decrease dust in an old house, forced air

My house was built in 1940. I have noticed the forced air pushes out a lot of dust. This is evident from lint collecting on the bathroom vanity below a vent. It only collects lint during Summer and ...
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52 views

furnace question

I have a tenant that constantly sets the thermostat at 90 degrees for the heat. I have told her several times to stop because she will burn the unit up. What are the consequences of this and how long ...
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28 views

Why won't my furnace turn off after replacing the igniter?

My igniter on my Frigidaire furnace went out. before replacing it I reset a limit switch that set off. I changed the ignitor and everything works, however now the thermostat is not shutting it down at ...
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125 views

Will heat set off a smoke detector placed in an attic?

A heating furnace is in a partially floored attic. used for storage only We have placed a smoke detector above the furnace and wonder if the heat in the summer would set it off.
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64 views

Should I Expect Reimbursement for a 2 Year Old Furnace? [closed]

I'm having an addition put onto my home and it is significant enough to warrant a larger furnace. Unfortunately, I recently had to replace my furnace. It is a two years old Trane brand furnace, two ...
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137 views

Replaced Thermostat, Furnace worked for 1 cycle now blows cold

Hello I just replaced my old White-Rodgers thermostat because it just wasn't working consistently (sometimes it would turn on the furnace, but mostly it wouldn't). I swapped it with a White-Rodgers ...
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66 views

Why won't my my furnace stop running unless I shut it off at the breaker?

I can't get my furnace to shut down unless I turn off the breaker. Why is this happening, and how do I fix it?
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63 views

Amana Furnace 90% eff. need help

Furnace will run for half a day to a day producing heat, then it will stop producing heat but the furnace will try to run still blowing air. Also, if I flip the switch off and then back on 10 seconds ...
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48 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 ...