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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1answer
48 views

Can I replace the permanent filter in my furnace?

In my furnace (ruud ubhc-17j14sfa), there is a permanent, washable filter. It was there when we moved in 2 years ago. The house is about 10 years old now. The filter is pretty simple, more like a ...
0
votes
1answer
52 views

Pilot lights, but main burners don't on furnace with no flame sensor

I have a Rheem furnace in my house. It recently stopped working. It is the type where the pilot is not always on. Anyways, the ignition will kick in, and the pilot lights just fine. However, the ...
4
votes
5answers
18k views

Why would my Goodman gas furnace start but not stay on for more than 2-3 minutes?

I've got a problem with my 15 year old Goodman furnace. It starts w/o problem, inductor begins working, hot surface ignitor lights up and ignites the gas. Then the main blower starts working and the ...
1
vote
0answers
168 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 ...
0
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2answers
69 views

Are my heat pumps using the right amount of power?

I'm trying to figure out if our two heat pumps are being power hogs and if there is something to do about it, or if they're operating normally. We bought our home recently and haven't been in it but a ...
1
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1answer
80 views

HVAC Contractor Didn't Install Drip Pan

I recently got the A/C unit and furnace in my basement replaced. When the company came out to do the quote, they stated that they thought I should have a drip pan, and the proposal that they gave me ...
7
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2answers
37k 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 ...
3
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2answers
17k views

Why won't my furnace turn off?

My furnace is running OK and heating the house. The problem is that I have the thermostat set to 66°F and it does not turn off when it reaches that temperature. I can turn it off manually at the ...
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0answers
59 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 ...
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0answers
72 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 ...
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1answer
82 views

How to wire a C-wire from a humidifier to a Carrier furnace?

I need guidance on a wire. One wire connects the humidistat to HUM. Another wire should go from the humidifier to COM24Vac. My COM is taken as you see in the picture. Is it an issue to wire the second ...
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2answers
2k views

Hvac Fan only blows in 'fan on' mode while heating

Our HVAC Fan only blows in 'fan on' mode while heating. In other words the fan will not blow in heat mode if switched to "fan auto". Both fan on and fan auto modes work when cooling. See image below, ...
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3answers
358 views

Can a furnace with a variable speed blower be used in a multistory house?

I just had an HVAC guy out to give me an estimate on a new Carrier Infinity series furnace and he said the second floor rooms will always be colder because the thermostat is on the first floor and not ...
4
votes
1answer
1k views

How many wires can be connected to the C terminal at the furnace?

I'd like install a new Wi-Fi thermostat. The old one didn't have a C-wire but luckily there is an unused wire on both sides (one coming out of the wall and one at the furnace not connected yet), so I ...
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1answer
84 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 ...
1
vote
1answer
522 views

How can I replace an old dial thermostat on an oil furnace with Hydrostat 3250 Plus?

I recently bought a home with an oil fired Biasi furnace that has a Hydrostat 3250-Plus attached. It uses an old analog round dial thermostat, and I'd like to replace it with a new digital (wifi) ...
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2answers
27k views

How can I determine why my furnace is not blowing enough heat?

During a cold spell last week when temperatures got down to -23f (-31C) my furnace started showing issues with blowing enough air and the air was not very warm. Last winter it did not have any issues ...
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2answers
66 views

Can I retrofit a 2-speed or variable speed blower on a Payne PG8UAA forced air furnace?

My furnace blower is rather loud and runs at one speed. I wish to have the blower run at a slower speed to mix the air in the house when the heat is not called for. I see some furnaces have ...
0
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0answers
37 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 ...
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2answers
74 views

wiring in a electric furnace to electrical subpanel

I have a 30 amp double breaker in my main home panel feeding my detached garage 100amp sub panel. Can i run a electric furnace with a 90 amp breaker in the subpanel. Or is this setup all wrong
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2answers
2k views

How do I reduce the noise from my forced air furnace?

We recently had a new forced air furnace and return installed. The unit works great, but the return (which is in an adjacent closet to the furnace closet) is quite loud. What are some solutions I can ...
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0answers
307 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 ...
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2answers
169 views

Rain water leaking around attic furnace

I bought a house a few months ago and when I bought it I noticed what appeared to be a water spot on the ceiling of the top floor. Of course I didn't do anything about it until heavy rains over the ...
0
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1answer
166 views

hooking up a humidifier on a carrier infinity furnace

Hello I would like to hook up my desert spring rotary disc humidifier to my new carrier infinity model #59MN7 furnace. I see the control board in the furnace has a HUM (humidifier) terminal and a ...
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4answers
1k views

Is interior fresh air venting suitable for new furnaces?

I have two new Carrier Infinity CNPVP high efficiency direct-vent furnaces in my basement for my 3500 sf house. The air intakes for both units are not plumbed outside but instead are drawing air from ...
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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) ...
11
votes
6answers
30k views

Does lowering the blower speed of a forced-air furnace lower its efficiency?

My gas furnace has two options for the blower speed: MED, and MED-HI. It had been set on the higher speed, but that was too harsh, so I lowered it to the slower speed. Does that have any impact on the ...
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3answers
217 views

Closing off heating ducts

We have a natural gas furnace that currently heats our entire 2400 square foot home. We plan on putting in a rental suite in the basement which will require closing up all the duct work into the suite ...
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1answer
7k views

Why is my furnace blower running at low speed?

My Payne gas furnace (PG8UAA 42091) automatically shuts down after it lights and burns for two minutes. It then gives a 33 fault code. I've done some research and some testing and have narrowed the ...
3
votes
5answers
25k 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 ...
1
vote
1answer
166 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. ...
3
votes
1answer
111 views

Furnace: are flames in between the tubes bad?

In a Carrier Weathermaker 8000 gas furnace, is it normal for some of the flames to be coming out of the spacers in between the tubes? It seems like they shouldn't be there, since they aren't going ...
1
vote
1answer
60 views

Actual efficiency of an old oil furnace?

We purchased a house with what appeared to be a relatively well-maintained oil furnace, about 30 years old (installed in 1984). We don't have any records of annual oil usage, or any way to find that ...
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0answers
43 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 ...
1
vote
1answer
439 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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0answers
4k views

Why does my pilot light go out continuously? [duplicate]

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 ...
3
votes
5answers
75k views

Why does my pilot light keep going out?

My furnace pilot light keeps going out so I changed the thermocouple. Now the furnace will come on and heat up to the degree set on my thermostat, then the pilot light will go out and the furnace will ...
0
votes
0answers
23 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 ...
2
votes
1answer
41 views

0v at DC thermostat terminal in furnace

I have an old (mid 80s) Rheem gas furnace I hope will last me through at least one more California winter. It's been known to go down into the upper fifties, so it has its work cut out for it. In any ...
0
votes
1answer
62 views

Furnace Fuse Blows Immediately

This afternoon, our Ruud furnace suddenly stopped working. After poking around a bit, I realized that the 3A fuse on the control board had blown. I ran to the hardware store and replaced it, but no ...
0
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0answers
230 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 ...
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0answers
7 views

Can I use any C terminal on a furnace to supply power to a thermostat? [duplicate]

I have a dual heat system with a gas and electric plenum. trying to install a wifi thermostat and found that the C wire on the furnace is connected but once it goes up and through the electric plenum ...
0
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0answers
60 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, ...
3
votes
1answer
131 views

How does old wood furnace work?

My mother in law has an old wood furnace in her workshop. It obviously is different than the typical wood stove you see. Does anyone have one of these? Or can anyone explain the theory behind its ...
0
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0answers
70 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
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2answers
69 views

Replace or wash this furnace filter?

My mom's furnace has ductwork until right next to the furnace, where the return air instead goes into an obsolete electronic air cleaner that is basically as big as the furnace itself. The issue is ...
5
votes
6answers
63k views

How much energy will continuously running a furnace fan use?

We have a bi-level (tri-level? There's a small entry way and utility room, then an upstairs living area and master bedroom and a downstairs living area with bedrooms) in mid-Michigan. The downstairs ...
0
votes
1answer
76 views

Cant I just use a 24v wall instead of a tranformer?

I can just use a 24v wall transformer that I have plugged into my sprinkler system and use that in place of the transformer on my electric Central coleman furnace right? I would connect the hot line ...
2
votes
1answer
252 views

What is the optimal duty cycle for a furnace?

A heat load calculation of my home says it requires ~36K BTU/hr of heat at a normal winter temperature (40°F), and ~52K BTU/hr at the design temperature (24°F). An HVAC contractor has proposed ...
0
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1answer
45 views

How do I switch the furnace to heat mode?

I have an older good Sears furnace. It was on cool mode this summer and the fan could come on. I can't find how to switch it back to heat mode! Thanks. Linda