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.

learn more… | top users | synonyms

2
votes
0answers
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: ...
2
votes
0answers
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 ...
2
votes
0answers
455 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 ...
2
votes
0answers
291 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 ...
2
votes
0answers
222 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 ...
1
vote
0answers
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 ...
1
vote
0answers
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 ...
1
vote
0answers
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.
1
vote
0answers
79 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 ...
1
vote
0answers
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 ...
1
vote
0answers
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 ...
1
vote
0answers
135 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 ...
1
vote
0answers
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?
1
vote
0answers
183 views

Why would a gas furnace shut down after 20-30 seconds?

I have an 18yo Lennox gas furnace (Modle 23G89). It starts and runs for 20-30 seconds then shuts off. The light blinks in a steady state- no code. Then I removed the filter to guarantee a clogged ...
1
vote
0answers
88 views

How to clean carbon build-up on Honeywell whole house air purifier made of aluminum?

Bought a house recently that has a Honeywell F300 whole electric house air purifier/cleaner. The cell's aluminum fins have a black baked-on dust that I expect is preventing the unit from working as ...
1
vote
0answers
55 views

Testing the exhaust of a natural gas furnace?

I recently had maintenance performed on my natural gas forced-air furnace. During this maintenance, the technician went outside and used an electronic handheld device with a wire-attached probe to ...
1
vote
0answers
47 views

Identify/troubleshoot this millivolt furnace valve

I have an old millivolt gas furnace that's stopped working. The pilot stays lit fine and the thermopile generates about 360 millivolts, and there's no problem at the thermostat (checked voltage and ...
1
vote
0answers
1k views

Can I use the T terminal in my furnace as the C for a Wifi Thermostat?

I've read many posts on this, and believe I know what to do, but want to make sure. My furnace (a Lennox G14 Series) does not have a C terminal which needs to be connected to the C terminal in my new ...
1
vote
0answers
110 views

Furnace reset problem

I have a new Goodman high efficient furnace model number GMH950703BXAG1. And this is the problem I'm having now: Turn on the furnace power (after ~1 hour off) Turn on the thermostat with Temp ...
1
vote
0answers
198 views

How can I install a furnace register in a kitchen-cabinet toe kick?

I'm planning to install new kitchen cabinets. I'll be covering up the kitchen's existing sidewall diffuser with new cabinets, so I'd like to relocate it to a new register in the toe kick of the sink ...
1
vote
0answers
154 views

Why won't a NEST that shares control of a furnace with a conventional thermostat turn on the heat?

I have three floors in my home. The bottom floor has its own gas furnace and the 2nd and 3rd floors share another gas furnace. Everything was working great until I added a NEST to the first and ...
1
vote
0answers
121 views

How should I shut down a woodburner that is attached to an electric furnace for the night?

I have a Monarch Add-A-Furnace wood burner connected by ductwork to my Armstrong Air electric furnace. I use the wood burner when it gets really cold outside, but shut it down at night because I do ...
1
vote
0answers
3k views

Why is my furnace limit tripping?

My furnace is tripping the high limit. It is a Downflow Payne 90+ have replaced the limit switch. I pulled the blower door off and checked all vents to ensure they are open and it still short cycles. ...
1
vote
0answers
2k views

What's causing my draft inducer to stay on?

I have a new, 3-year old, high-efficiency, gas furnace in my home. I recently realized that my draft inducer, which normally kicks on before the burners and before the main blower, is not stopping. ...
1
vote
0answers
336 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. ...
0
votes
0answers
12 views

Why does my kerosene furnace stop running?

I am having issues for months now with my kerosene furnace for a mobile home. It is a beckett relay and becket flame box. I have changed electrodes, I changed eye for flame sensor, the nozzle is not ...
0
votes
0answers
29 views

Where is this water coming from around my condensate pipe? (super confused)

Okay, so somewhat complicated story. When we bought our house 6 months ago the furnace was brand new but the AC unit was old. AC unit developed a leak that was expensive to repair, so we replaced it. ...
0
votes
0answers
34 views

Can a furnace safety limit switch with manual reset be changed out with an auto reset switch?

I have a Ruud natural gas furnace from 1987. Overall it works well. I've had my home warranty service send out an HVAC tech a couple times for the high limit switch needing to be reset. It's a manual ...
0
votes
0answers
37 views

Is the Thermostat controlling the wrong zone? (Multi-zone heating with gas furnace)

UPDATE 12-29-2015: I've poked around and found, what I believe is, the board controlling the zones (Trol-A-Temp Mini-zone). Before I make any changes there, I chose to replace the thermostat on the ...
0
votes
0answers
31 views

Oil furnace fan timing, limit temp setting

I just installed a new Crown oil furnace and a two wire thermostat. The furnace fires up fine but the blower won't turn on until it shuts down and the high temp limit control takes over. Then the ...
0
votes
0answers
75 views

My furnace has a C - common wire but air conditioner uses it - how to hook up smart thermostat?

I bought an ecobee3 smart thermostat which requires the C wire. At my furnace there is no circuit board but there was a diagram and I was able to locate the C - common wire, but it seems to be used ...
0
votes
0answers
48 views

new furnace hurts eardrums

I just got a new furnace in my 800 sq. ft apartment. Single stage 80% efficiency 40K BTU Coleman. It seems much louder than my old one. The burners and the blower. And when I walk past the (single) ...
0
votes
0answers
41 views

Furnace on the Fritz - Any help greatly appreciated

I have a Tran XL90 - Model #: TUX100R948W6 It does not turn on in the "Auto" position on the thermostat. The fan does come on in the "On" position. However, it doesn't blow hot air. It has 3 ...
0
votes
0answers
18 views

miller mobile home furnace

When I press the reset button my furnace turns on and goes what seems to be a complete cycle. At this time the heat comes from the register nice and strong. When it comes on the second time it shuts ...
0
votes
0answers
187 views

No C wire terminal on my electric plenum but there is on my furnace. How do I solve?

I had a brand new furnace installed recently but also now picked up a wifi thermostat. The problem I now encountered while installing the thermostat is that my system also has an electric plenum as ...
0
votes
0answers
44 views

wiring for rheem 2 stage furnace

I am trying to wire a Honeywell 2 stage thermostat to a Rheem classic 90 gas furnace. At the furnace there is a white wire with a red strand connected to the R post, a blue to the C, green to G, ...
0
votes
0answers
49 views

Need help with a Trane XR90 gas furnace not heating

Diagnostic blinking light is 3. Tried calling Trane with no returned call and its getting really cold tonight. 30 degrees. Help plese
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
0answers
69 views

What should I do if both the diagnostic LEDs are off on a Lennox G40UH(x)series heater control board?

My Ignition control Board on the G40UH(x)series both of the diagnostic LED's lights both are off, any suggestions in how to resolve this problem
0
votes
0answers
41 views

The thermostat is set at 73 however the furnace doesnot kick on until it is down to 67.

The 96 % goodman furnace was just installed. The service man changed the thermostat but I think her switched some of the wires. When I have it set at 73 it does not kick on until the tempature is ...
0
votes
0answers
7 views

How to wire a Feeder Furnace?

I have a feeder oil furnace and I need to know how to wire the oil burner to the oil control box please help
0
votes
0answers
48 views

What can cause short life of the igniter in furnace?

what could cause short life of silicon nitride 80v,IGN00145.furnace trane xcm95 2years old put in 3rd igniter.
0
votes
0answers
177 views

Furnace blower intermittently stops working

The blower on my furnace is set to be on constantly. The last two nights in a row I have woken up in the middle of the night to hear that the blower is not running and that the temperature is dropping ...
0
votes
0answers
29 views

What could cause the furnace to not come on after airing out the house?

Turned the furnace system off and manually turned fan on at the thermostat to air out the house after staining woodwork. Now the system is turned back to Heat and Auto Fan but will not cycle on. The ...
0
votes
0answers
76 views

Main burner will not light, but the pilot is ok

I have an old Heil unit 100,000 BTU, it has been working fine up until Tuesday night. The pilot light is on. I replaced the gas control valve, I know it has limit switches should I replace them all or ...