Tagged Questions

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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26 views

What would be your choice for a no frills good and reliable furnace? [on hold]

I need something solid and simple, something to last something that would cost around 1500$ or a little bit more. I have not done any market research yet so excuse me if I am not being realistic ...
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1answer
27 views

A professional to test asbestos safety in furnace ducts

We live in a rented house with an old furnace duct system (probably 1960's). There is asbestos-containing duct-wrap all around the ducts, and it starts to crumble in some places (it's located in the ...
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1answer
35 views

What could be causing my furnace burners to fire up, then shut off due to partially open door?

I have a 10 year old Carrier gas furnace that keeps shutting off every 24-48 hrs. First I thought it might be the flare sensor but then I checked the bottom door and it wasn't completely closed. I ...
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2answers
39 views

Very old furnace- I need a technician to inspect it-What would be a good check up list?

First of all you should know that this is about a 25 years furnace that is very simple and that if nothing is wrong with the heat exchanger it should last forever since, IMHO, the parts are very ...
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1answer
27 views

How do I check if this furnace switch the blower to second speed

My furnace is overheating and I suspect that the blower motor does not go into high speed. Can anybody say what is the cause or how can I check if it indeed switches to high speed? Here is the wiring ...
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0answers
27 views

With registers fully open I have unbalanced air flow upstairs vs downstairs

Upstairs the airflow is OK Downstairs I have 4 registers. Three out of four have very weak air flow while the fourth one is blowing like hell Is the problem in the furnace or in the air ducts?
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0answers
33 views

Asbestos in my furnace closet - should I get rid of it?

I have a home built in 1958 with a closet inside the house that contains the furnace. When the house was constructed this closet was lined with asbestos as a safety measure. How dangerous is it for my ...
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1answer
28 views

What temperatures are normal in this area of my furnace?

Please see the attached picture and pay attention to the "temperature dial" in the inset With the current settings the gas burner cycles like this -limit temperature 200F -at that temperature the ...
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1answer
39 views

Where do I connect the C wire in my furnace?

I am upgrading my thermostat to a Nest, and would like to add a common wire. My current furnace controller doesn't have a C terminal, but the current thermostat wire has 2 unused wires (black and ...
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1answer
54 views

What is wrong with my gas furnace?

Note: the below was solved. It was a loose wire between the controller and the gas valve (the white wire on the diagram) This is about an old UltraMax Olsen HCS2 81AD gas furnace it looks like this ...
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0answers
23 views

My electric furnace won't run on auto [closed]

My electric furnace won't run when the fan is set on auto. If I turn it to on it runs. I jumpered the R & G wires and the fan ran. What next?
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4answers
64 views

Is it safe to use an HVAC system even though the duct wrap contains asbestos?

In our rental house the furnace ducts are very dirty. We brought an expert to clean it, but he said he just won't do it because the tape around the ducts (in the attic) is probably asbestos. After ...
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0answers
23 views

What is the smell coming through my HVAC system?

If I leave the furnace fan always running for an extended period of time (to circulate and filter the air), when the central AC turns on there is a not-so-fresh smell that is emitted through the ...
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1answer
36 views

Is there any way to stop the air leak through my furnace without compromising its operation?

My house has an 80% efficiency gas furnace in an interior mechanical closet with the return air path below the furnace and through a grille under the closet. However, since the furnace is not a sealed ...
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1answer
47 views

How can I connect a humidifier to a Goodman dual fuel heating system?

Purchased a dual fuel goodman system with CTK04 comfortnet thermostat. The thermostat installtion guide shows wiring of a humidifier to the (2) Hum terminals on the furnace IFC. My furnace model is ...
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0answers
23 views

How do I get the main furnace blower to come on when the wood burner furnace calls for heat?

I need to know how to wire the gas furnace blower to come on when the wood burner's blower kicks on.
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1answer
54 views

What could be causing vibration in my furnace?

I have a vibraton in furnace only when flame is lit. Blower motor seems fine. Is this vibration normal? Recently replaced inducer motor. Heat exchanger has been replaced once. Does not appear to be ...
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2answers
258 views

Where's the C terminal on my boiler control?

The new thermostat I purchased doesn't run on batteries, and needs 24 volt power. I have only a red and a white wire connected between the boiler and the thermostat, but there is also a third, unused ...
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1answer
22 views

If flame sensor will affect Motor assembly's functionality of furnace? How does that work? [closed]

I have two Air conditioning company. A is the self-hired for my A/C, and B is assigned by home warranty company. This summer, the technician with A came out for an annual maintenance on both A/C and ...
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1answer
40 views

What could cause my old gas furnace to keep cutting out?

I have a old gas furnace that keeps cutting out. It turns on and the when it hits the temp it turns off and then when it turns on it will not give it gas. It will just sound like it blowing but no air ...
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1answer
133 views

What could cause a Trane furnace to not start heating?

I have a newer (2007?) Trane XL90 (model: tdx2b080a9422aa)forced air gas furnace. The problem I am having is the burner and fan will not start. The thermostat is set at 67 degrees and shows it is ...
2
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1answer
66 views

What could cause the furnace blower to come on constantly and no fire in gas burner?

When thermostat is turned up on my hot air furnace, the blower immediately comes on, blowing no heat, had it checked and with some luck the burner fired after about 10 tries of switching on and off. ...
2
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1answer
67 views

how to change furnace filter (bottom return) for Lennox G43UF

I have a Lennox G43UF furnace and I am not sure if I need to have both a filter for a side return and bottom return. If I do (which sounds logical), where would the location of the bottom return ...
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1answer
78 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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0answers
23 views

ComfortMaker GUH075 series high-efficiency (93%) furnace isn't making heat

It worked a couple of days ago but today the fan blows but the burner doesn't seem to come on. The status indicator inside the access panel flashes four times but I can't find any reference to tell ...
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0answers
332 views

Where to connect a c-wire on a furnace with existing two wire mercury thermostat

My existing thermostat is an old mercury two wire device, heat only. Looking to upgrade to a better model, but I need to run a c-wire. I don't know where to connect the wire at at the furnace, any ...
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0answers
23 views

Options for humidifier

Winter is approaching and the cool weather is making the air dry in our home. We're using room humidifiers but want to install a humidifier which can go on our furnace. However, we have very limited ...
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2answers
64 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 ...
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1answer
57 views

Heating system won't blow warm air

Turn my heat on via the thermostat. My oil fed burner kicks on and is lit up (heat is being made). The system is sucking in air to feed the system. Only problem is hot air never makes it out the ...
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1answer
33 views

What could cause a mobile home furnace not to light?

Our furnace won't lite. Mobile home pre 80. There is no name that we can see. The pilot light piece looks to be changed. Pilot light won't light. We don't hear or smell gas. It has settings last, 2, ...
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1answer
119 views

Wiggle, wiggle, wiggle wires on Furnace Pressure Switch makes it work — should I replace Switch?

My Furnace (a Rheem Criterion II Gas Furnace - model RGLH-07EAMGR) has had a problem for a while that we've just been living with but I can finally afford to do something about it. What happens is ...
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1answer
227 views

Why is my water expansion tank leaking?

I live in the northeastern US and we just turned the heat on (oil) and this morning I went down to the basement and saw this: The water is coming from the plumping above something labeled "water ...
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1answer
45 views

Condensation running down pipe connecting furnace thru ceiling to chimney

I had a new downflow 80% efficient furnace installed in 2006. I don't use it regularly as I normally heat my home with my woodstove (separate chimney). But I have used this new furnace many times ...
2
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1answer
38 views

How do I determine/control which heat source is used (heat pump, oil)

I have a heat pump and an oil furnace for backup. How does the HVAC system know when to use the heat pump and when to use the oil furnace? Specifics: I have a Honeywell TH8320U1008 thermostat ...
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1answer
411 views

Which terminal should be used for a ā€œCā€ wire when none are labeled ā€œCā€? Older electric furnace/heat pump

I have an all electric air handler/furnace connected to a separate AC unit and it is also a heat pump. I've purchased the latest and greatest Honeywell WiFi "Smart" Thermostat and it needs a C wire. ...
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0answers
157 views

Furnace not working properly with digital thermostat

I have been attempting to use several different types of digital thermostats to replace my old mercury thermostat, however none of them are able to control the furnace properly. All of them are able ...
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0answers
130 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 ...
2
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1answer
88 views

Could a high limit switch cause the furnace blower to run continuously?

My furnace was running fine. The I noticed that the unit was blowing cold air. Checked the furnace burners and they were off. I turned off the unit on the thermostat and the blower continued to run. ...
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0answers
35 views

Steps for annual maintenance on a fuel oil furnace?

We have fuel oil and this year I'd like to try and maintenance the furnace myself: By "maintenance" I mean "clean it up so that it runs well throughout the winter." Just a basic tuneup and ...
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0answers
48 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 ...
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0answers
29 views

Which should I do first? replacing furnace or resurfacing concrete floor?

I'm going to get two things done in my basement soon (by hiring professionals), but I'm wondering what the right order of operations is. One task is to replace the gas furnace that sits near the ...
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1answer
49 views

What could cause the blower in my furnace to come on?

Ok my blower just turned on, my propane furnace and it's not in operation due it being summer. My thermostat is set at 65 and the room temp is 78. The heater never actually fired it was only the ...
2
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1answer
66 views

Is it a problem that I have two of each color wires on my Honeywell thermostat?

I am thinking about upgrading my Honeywell thermostat. Every thing I have seen describes / shows a single wire for each color. My current thermostat has two wires connected to each terminal (two green ...
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0answers
156 views

Why is my new high efficiency furnace blowing cold air sometimes?

Why does my new furnace high efficient Payne furnace blow cold air,not constantly but at least 3 different times in a day, my thermastat is set on auto but when the weather is cold outside it will ...
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1answer
127 views

Can I relocate my furnace exhaust?

When my new furnace was installed, the vent was put outside the house next to landscaping bushes. It has killed one of my bushes. It used to be vented up to my roof and out. Can I move this outside ...
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0answers
80 views

Will a single ductless mini-split heat pump be able to distribute its air evenly throughout my ranch house?

I am in the middle of a deep energy retrofit of my house, and a quick-and-dirty online manual J calculation of the projected loads once my projects are completed shows an estimated heating and cooling ...
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1answer
35 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 ...
2
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1answer
198 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 ...
0
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1answer
104 views

Why does my oil-furnace's on-demand water heater go tepid and then return to full heat?

We have an issue with the hot water from a 2004 Peerless oil furnace with on-demand hot water. The shower starts at full temp, but quickly goes tepid (too cool for a bath/shower, but not ice-cold) and ...
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3answers
24 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 ...