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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7
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6answers
10k views

Where should my furnace filter go in a Lennox G40UHX series furnace?

I have a Lennox G40UH(X) series furnace, which is installed in our attic (We have a single-story house on a slab). Because the furnace is installed in the attic, it is "laying down" on its side, and ...
4
votes
3answers
4k views

Why does the pilot light go out when the furnace is running?

Every time the furnace fires up, it blows out the pilot light. Sometimes it will run a full cycle and blow out when it shuts down, and sometimes it will blow out about a minute into the cycle. We ...
2
votes
2answers
424 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, ...
4
votes
1answer
3k views

What would cause my furnace to only work with the filter removed?

My Carrier furnace works fine without the air filter in place on the return. With the filter in place it works for a while and then stops with a complaint about "limit, or flame rollout is open" ...
3
votes
2answers
5k views

What would cause a furnace to shut off prematurely?

I've got a Carrier Weathermaker 8000 furnace that shuts off about 90 seconds or so after ignition, started doing this recently. I get flashing code "33" which indicates: The code indicates: 33 ...
3
votes
2answers
566 views

What is this name of this vent attachment next to my furnace?

What is the name of this silver vent attachment thing at the bottom of the picture? It is attached to the side of our gas furnace. The black part is an insulated air duct which goes to a vent ...
2
votes
1answer
4k views

Why does my pilot light go out when I release the pilot light knob?

My furnace pilot light will not stay lit. I can light it and depress the pilot switch for 2 minutes. But, once I let go of the button, the pilot immediately goes out. Does my thermocouple need ...
0
votes
1answer
61 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 ...
1
vote
1answer
186 views

Why does my Thermo Pride oil furnace need constant restarts?

We have a Thermo Pride oil furnace that requires frequent restarts to run. We just purchased the house and had the annual service/safety check completed as it was neglected for several years. When the ...
0
votes
1answer
192 views

Water has quit running thru my humidifier.

Furnace humidifier dry as a bone. have changed the filter, duh, that is the only thing I know how to do! Bottom line, there is no water running through it.
2
votes
1answer
358 views

Can I properly install Roxul mineral wool batts in a mostly-drywalled stud bay by pushing them up from below?

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 ...
8
votes
2answers
1k views

Should I insulate steam pipes in the basement?

I have a steam-radiator heating system. The furnace is in the (unfinished) basement, and the steam-carrying steel pipes spread out across the basement ceiling before going up into the rest of the ...
0
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3answers
26 views

Can't select some temperatures with the thermostat of my furnace

I have a problem with the thermostat of my furnace. This problem is wired but I'll try to explain it as clearly as possible. When I turn the button of the thermostat, some temperatures can't be ...
2
votes
2answers
339 views

What could be causing my gas furnace to make a loud noise?

I have a comfort air natural gas furnace when it call for heat,their is a loud boom noise,could the hot surface ignitor have a crack or needs replacing?
1
vote
2answers
132 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.
2
votes
2answers
2k views

Should my furnace closet have this huge duct opening into the unconditioned vented attic?

So my interior furnace closet has a huge duct in it that connects the closet to the unconditioned vented attic right above it. Needless to say, this is a huge air leak into the conditioned part of the ...
1
vote
0answers
132 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 ...
0
votes
1answer
566 views

I have just reset furnace due to a trouble code, what should I monitor or re-do over the next few days?

My furnace was throwing a trouble code. The code was 31 and for my manufacturer (Bryant) and others thats is a pressure switch code. I was able to resolve this code and get my heat back on simply by ...
0
votes
1answer
203 views

How can I prevent my furnace exhaust pipe from freezing?

My furnace keeps on turning off because my air intake freezes. The reason it freezes up is because my neighbors exhaust vent blows directly on it. What can I do to prevent this?
0
votes
2answers
253 views

Would a failing igniter cause my furnace to blow cold air?

I noticed tonight my furnace was firing up, but not actually blowing out heat. I turned the thermostat down so it was no longer triggering it, let it sit for a couple of minutes, and then turned it ...
1
vote
1answer
4k views

Which way does the air flow through my furnace?

Below is my furnace and I need to change the filter however I am unsure which way is the airflow direction. Red or Blue?
0
votes
1answer
55 views

Furace fuse blows when Aprilaire humdifier is turned on above 35%

I live in a pretty old house and have a Carrier furnace with an Aprilaire humidifier attached to it. The device that controls the water flow, I guess it's a solenoid, is visible on the exterior of ...
2
votes
1answer
167 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 ...
2
votes
1answer
367 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 ...
0
votes
1answer
304 views

What is this noise coming from my gas furnace?

Whenever I change my air filters in my furnace, I hear a boom noise. The last time I called DEER and they came out and fixed the problem (I can't remember what the part was called that was needed). It ...
0
votes
0answers
120 views

Why does my furnace make sounds like a tuba when kicking on?

I have a 21 yr old Bryant furnace. Recently it started making a horrible noise when the heat first kicks on. It sounds like someone playing the tuba. It only lasts a few seconds, but it's loud ...
1
vote
1answer
205 views

What to do first in a house with poor thermal performance and high energy bills

I just moved into a house and am a little bit disappointed in its thermal performance so far. It's winter and cold outside, and the furnace heats the house up pretty quickly, but then the house gets ...
0
votes
1answer
120 views

What is this pipe - should I be worried?

We found it behind a wall, it is a bit more than 10 inches wide it has about an 3/4 inch of concrete between metal. It was jaggedly broke off on the bottom in the basement ceiling. It is also ...
0
votes
1answer
634 views

Why doesn't the “fan on” mode work after I installed a new thermostat?

We moved into a new house. I installed a new Hunter Thermostat. I have a furnace only and the old thermostat only had 3 wires connected. SO I connected those three wires (G, RH and W/B). The ...
0
votes
1answer
320 views

Furnace keeps resetting

My trane xr90 furnace keeps resetting just while it is in its "heat up phase" I'm a laymen but a description of what is happening is like this... The furnace gets a call for heat, it makes a sound ...
0
votes
1answer
201 views

How close can an electric water heater and an electric furnace be to each other?

How close can an electric water heater and an electric furnace be to each other? My water heater is 7 inches from my furnace. I need 4 inches so that I can install a water softener and wash sink. So ...
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vote
0answers
115 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
votes
1answer
480 views

Which way should furnace filter face?

I replaced my furnace filter (every 30 days) but upon Googling, I've found it has to go certain way. It's suppose to go the way where the arrow points for the airflow. But my filters have no arrows on ...
1
vote
1answer
7k views

Forced air system blowing cold air through bedroom vents, hot through the rest

I'm in a rental house for the next few months which hasn't been particularly well maintained. It does have a newish looking Goodman gas furnace, yet the gas bills seem outrageous to me ($250 per month ...
0
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0answers
63 views

Can I use my forced air furnace to heat water for radiant heat too?

I moved from Europe to USA 4 years ago and I was wondering if it's possible to combine forced air heating with the heating that uses radiators. My idea is to use the furnace for forced air to heat up ...
1
vote
3answers
615 views

Should I leave the fan switch on my thermostat set to fan rather than auto?

I purchased a new Amanda Furnace in Oct'2013. I am told in order to maximize a warm, consistent room temperature I should set the thermostat to the Fan position rather than the Auto position. Does ...
1
vote
1answer
4k views

How can I figure out why the low voltage furnace fuse blows on heat but not cool?

I have a Tempstar Model NTC6100KFG1 gas furnace. Furnace was working fine through the summer blowing the AC. It's been off for a month or two as we've been changing seasons here. When I went to turn ...
0
votes
1answer
1k views

How do I connect a WiFi thermostat to my furnace's primary control?

I would like to install a Honeywell WiFi controlled thermostat to connect to a Honeywell R7184U primary control. My question concerns the "C" wire. The R7184 has the terminals labeled 1, 2, 3 and 4 ...
2
votes
2answers
1k views

Furnace flashing 4 times (Ducane)

My Ducane furnace flashes 4 times, runs for 5 minutes, and then the burner goes off. When the limit switch is jumped it runs good. What needs to be changed here?
0
votes
3answers
560 views

Furnace installation

I have new 2 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 ...
0
votes
2answers
539 views

Should I replace my Pressure Reducing Valve?

A few weeks ago, my oil-fired water boiler started continuously leaking water out of the pressure release valve on the top of the unit. I know this is leaking steadily because it drains into a 5gal ...
0
votes
2answers
766 views

Why doesn't my gas furnace ignite?

I had a Lennox slp98dfv installed last year - it has a surelight ignition - it now just blows cold air - so I assume the pilot light is out - but not sure how to light it - as u cannot manually ignite ...
1
vote
3answers
7k views

How do I wire a humidifier without a 24 VAC IN terminal?

The instructions for the humidifier I'm installing says to connect the humidistat wiring to the two terminals "marked 24 VAC IN". My furnace doesn't have terminals marked that. I have R,C,W,Y.G. Am ...
1
vote
0answers
114 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 ...
3
votes
4answers
5k views

Why would a furnace overheat with a standard density filter?

Some time ago I found my furnace (gas, forced air, downdraft) was getting stuck on, blowing cold air. I could reset it, but it would happen again after a while. After calling out a service man, I ...
0
votes
1answer
139 views

Legal requirements regarding 100% asbestos duct work [closed]

I am renting a condo. After starting the heater, dusty air came out of the registers, so I called out a company to clean the ducts. They verified the ducts are 100% asbestos and cannot be cleaned. ...
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0answers
1k 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
1answer
172 views

Can I install a flow through humidifier on either side of the duct?

I was about to install a Wait6000 whole home humidifier when I hit this snag in the plan. On page 3 of their manual (PDF), it says the cold air return duct must be at least 10" wide. The diagram ...
5
votes
3answers
547 views

Should the fill line be removed when decommissioning an old oil tank?

So, I have a contractor decommissioning my old 650-gallon oil tank. There is a 3" metal tube coming out of the ground from the tank that is what I believe to be the receptacle used to fill the tank ...
0
votes
2answers
11k views

What size breaker and wire do I need for central air conditioning?

I am getting ready to hang drywall in my basement but before I do that, I need to run wire from the main panel upstairs to the future location of the central AC furnace through the basement ceiling ...