Questions tagged [furnace]

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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972 views

Lennox furnace 3 flashing lights

Have a new construction house, and lived here about 2.5 yrs. Turned on my furnace last night worked fine. This morning, it kept turning on then kicking off with no burners coming on. I noticed the ...
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180 views

Furnace draft inducer switch tripping

I have an older furnace and a brand new natural gas instant water heater that I installed. I only start this way because the furnace had one thing break last year, so I'm not sure if things on it are ...
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1answer
70 views

Fan comes on but the air conditioner does not

During hot days when the air conditioner is on a lot it comes to a point in the evening when the air conditioner shuts down and the fan (from furnace) stays on. This will go on all night as the house ...
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71 views

Converted Oil Furnace to Natural Gas - Fuel Smell Issue

This weekend, we had our fuel oil furnace replaced with a natural gas one. The oil furnace broke near the end of the winter and we were waiting for a deal to kick in on a whole new furnace + A/C unit. ...
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2k views

Furnace Mainboard wiring with AC unit

I went to install a Nest on my upstairs HVAC unit. After installing the Nest I thought it was functioning properly. The next afternoon I came back to the house It was still hot, so looking into this ...
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53 views

Lennox G20 furnace

I was reading about using the T terminal for the C wire for internet thermostat. I have different wiring Thermostat Furnace RC R W. W Y Blank Rh T G. G ...
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615 views

Goodman furnace starts after turning on / off 7 times

I have a Goodman furnace from 2000 has been running great until recently it does not seem to cinc with thermostat. when you shut unit down and turn back on it will go through all motions of starting ...
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45 views

furnace wont kick in

My furnace seems to work intermittently. overnight its seems to stop... i have checked the thermostat and it shows says it is heating. fan is on auto, but nothing coming out. when i turn heat to off, ...
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23 views

coleman gas heat only furnace,

When heat comes on, furnace runs for about 8 mins then cycles off. When the heat clicks off I get a switch open code from the board. While the furnace is running I get a normal operation code. As soon ...
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2answers
436 views

Furnace Blower fan doesn't start

I have a keeprite high efficiency furnace that Was a part of my new house. It's 2016. The Honeywell thermostat is set at 23 deg C. This is what happens when the temperature is below the cut-off I ...
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62 views

Is a side-vented furnace the same as a high-efficiency furnace?

I'm replacing the thermostat in my home and there is a separate step for "high-efficiency furnaces that are greater than 90% efficiency" I have a furnace that is power side-vented with a PVC pipe. Is ...
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231 views

Thermostat for my furnace has no power during fan-off delay?

I have an older Tempstar 5000 furnace and a newish Honeywell wifi thermostat. The furnace works fine and the thermostat appears to be wired correctly (4 wires including C wire) but for some reason, ...
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161 views

Framing distance around chimney in basement

I'm in the process of trying to air seal my basement. During the process I pulled out some fiberglass insulation that was shoved on each side of my masonry chimney in the ceiling where it enters the ...
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3k views

Furnace keeps going out during cold periods, needs procedure to reset

I have had a reoccurring problem with my Rheem gas hot air furnace. Model# RGVC 07EA ER and SER #KN5D1041F47889671. This is a 28 year old furnace that is a horizontal attic mounted furnace. I have had ...
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168 views

Suburban SF-30 RV furnace has trouble lighting when it is cold

I have a Suburban SF-30 furnace in my camping trailer. It runs most week days during the winter so it gets a lot of use. I have been noticing for a while that it struggles to light. It seems the ...
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235 views

Furnace Ignitor Ticking Continuously

My furnace is a Carrier 58GS075. It seems to cycle correctly: Igniter sparks and ignites* 20-30 second pause. Main burners are opened and ignite. 30-60 seconds and blower turns on. Remains on until ...
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38 views

Is inlet pipe required for a 95v furnace

In mid 2015 we got a 95v American Standard furnace. After a year, we got inspection done which was required for warranty. The inspection guy said No intake pipe is ran at all. Unit must have an intake ...
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1answer
8k views

Goodman gas furnace limit switch opening, blower only runs with a/c

I apologize in advance for some of my incorrect terminology. My father has a 2004 Goodman GMH80904BN gas furnace with a/c. The a/c has functioned properly all summer here in Ohio, we have recently had ...
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345 views

Installing new thermostat without a C wire. Can I use my heater/R wire instead? Random 13V as well

I'm installing a thermostat, but I don't appear to have a C wire. My old thermostat had R/RH,Y,G,and W. It's an AC system that was setup before I got here. The actual AC unit is a long way away and ...
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103 views

Building a deck - can I extend the side wall vent of my propane furnace underneath it?

I'm building a low deck outside of my house, and the vent wouldn't have a 1ft clearance. Deck extends about 7ft out from the house. Would it cause any problems if I were to extend the vent's 2inch ...
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1answer
957 views

Honeywell VR8300A3500 Single Stage Heat Gas Valve to Ecobee3 with C wire

Hey everyone have a quick question regarding a honeywell VR8300A3500 Single Stage Heat Gas Valve and the introduction of a Ecobee3 wifi enabled thermostat with a "C" wire. just want to make sure i am ...
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118 views

Asbestos? What do you think?

I originally thought so, but now I'm not so sure. Thoughts? It was located around HVAC vents.
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679 views

Nordyne furnace doesn't start at all (model gl1ra 090c-12b 903785GA)

What are the reasons this model furnace won't start at all anymore. No sound when I flip the on switch. I already tried replacing the ignitor and that didn't work. Thank you for any help!
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8k 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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1answer
54 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 problem?...
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165 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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36 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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1k 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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624 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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124 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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3k 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 ...
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154 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 ...
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361 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 setting ...
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224 views

Would a radiant barrier help stop this heat transfer?

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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314 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 ...
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316 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 ...
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8k 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. ...
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1answer
617 views

Furnace failing intermittently, is it a faulty furnace pressure switch?

Furnace info Type: York Stellar Plus (HE down-flow condensing) Model number: P2UDD12N09501C Problem My furnace is intermittently failing, i.e. it stops producing heat. When it fails, the induction ...
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1answer
722 views

Temperature in Condo hotter than thermostat setting- Gas Furnace

I recently bought my first place (a condo) and I have a gas furnace. The thermostat is set for 72 and most of the time it seems to be following this alright but periodically even though the thermostat ...
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32 views

connect switch handy box to plenum?

would it be code to attach the 2 x 4 handy box with the switch on the plenum as the old furnace set up would hook up on the new furnace with the bx cable coming off bottom of handy box to furnace ...
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23 views

Furnace fan operates only when heating is on

I don't have AC unit at my house, and summer heat is really bad when I sleep at night in my bedroom upstairs. Since I don't have AC, I think manually setting the fan "on" while I sleep will ...
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21 views

vinegar for Trane furnace

I installed a new gas heater with a condensing unit in 2019 winter. Here is the detail. My question is... Every year, I'd better pour some vinegar after opening the cap of the picture? If yes, how ...
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9 views

air filter location for Nordyne Furnace Model KG7SL 090D-35C

I'm trying to change and replace the air filter for my furnace. It's Nordyne Furnace Model KG7SL 090D-35C. Picture attached. However I can't figure out where the air filter is located. Can someone ...
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10 views

Installing a Honeywell HZ432 for four zone wireless heating

need help with wiring setup. Current setup Gas furnace (heating, no cooling): standard four zone gas furnace setup with hot water circulator 4 zones (3 wired, 1 wireless) Setup: Honeywell THM5320R (...
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25 views

Why is the combustion chamber on my furnace vibrating and humming when the air conditioner is on?

I replaced the blower motor, blower wheel (squirrel cage), and run capacitor in my Goodman GMS80904BNBB furnace (1994 model I believe) because it showed signs of bearing and capacitor failure. First ...
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24 views

Furnace breaker wont stay on

I tried turning on the AC and it won’t run. Checked the breaker box and the furnace breaker is flipped. The breaker won’t stay in the on position When I flip it bacm. So I must have a short ...
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13 views

Connect two LP-GAS High-Eff +95% Furnaces to one LP Tank

Connect two LP-GAS High-Eff +95% Furnaces to one LP Tank will reduce supplier refill to one location on House. Furnaces 100K BTU and 60K BTU. To reduce refill to one location (currently two tanks on ...
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9 views

Increase fan speed (wiring) on Bryant Legacy Furnace

I have a two story house. The second floor gets hot even with the AC going. Right now, with no AC running and the thermostat set to “fan on”, the blower is set up to run at low speed. Since it’s a 3 ...
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10 views

Weak airflow after replacing furnace and add new A/C

I had Furnace HVAC before and I made a mistake not knowing what I had. We never had A/C. Recently I purchased this package from Costco: LENNOX ELITE SERIES AIR CONDITIONER SYSTEM XC13 LENNOX 80% 2-...
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21 views

Leaky expansion tank overflow

I have a gas fired furnace with forced hot water. Off of the expansion tank there is a drain pipe. Recently it started leaking, roughly a mason jar a day. Why is this happening and can I solve the ...