(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

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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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2answers
76 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 ...
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1answer
577 views

Can I have a separate thermostat for a wood boiler?

I want to wire a separate thermostat for my outdoor wood boiler so that just the furnace fan will come on without the propane kicking on. This is a Coleman furnace. Is this possible and if so, how ...
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22 views

Need to run a “C” wire to thermostat but control board has no “C” [duplicate]

I am looking to replace a thermostat with one that needs a C wire... which my current thermostat does not. I have some extra wires in the thermostat wiring that are unused... so I went down to the ...
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2answers
167 views

Gap between 6“ dia wall thimble & 6” hvac pipe

I bought a 6" dia aluminum wall thimble to vent my 6" dia hvac steel exhaust pipe through to the outside. However, the diameter of the 6" thimble is actually 6 3/4". How do I effectively insulate the ...
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164 views

Thermostat replacement

My old thermostat is a carrier t-stat and has a jumper wire between o/w2* and L I am upgrading to a honeywell wifi t-stat, should I install the same jumper wire on the new thermostat? I have an ...
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0answers
149 views

How can I install a floor register in bathroom

I need to install a floor register in my bathroom (which I am currently remodeling). I plan to put one into the floor under the window where it used to be. The old register came up through the floor ...
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2answers
1k views

Installing Honeywell WiFi Thermostat

I am trying to upgrade to a programmable thermostat. I bought the Honeywell RTH9580 with WiFi. I can get power to the new thermostat and get the fan running. However, it will not work when the fan ...
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154 views

What could be causing our air conditioner circuit breaker to keep tripping?

Our air conditioner circuit breaker marked "AC", is tripping frequently after the AC unit works for a while. Sometimes as long as an hour or more and, sometimes as short as few minutes. We were told ...
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2answers
757 views

Can I wire a Bathroom Fan to two Switches in Parallel?

I want to control a bathroom exhaust fan with a wall timer, and a 24 vac relay. Basically both switches would be wired in parallel. Is this safe to do?
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2answers
138 views

What are the possible reasons I am not getting cold air from my air conditioner?

my heat pump outside is working but my central air conditioning/heating unit in the garage makes a hissing sound or faint sound of water running. There is air coming from the vents. The very last time ...
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97 views

What steps are required to convert R-22 Freon to a new R-410A Puron system?

I am house hunting in Houston. Every 2000-2004 house we've seen so far uses old A/C Unit and coils for R-22 Freon and not the newer R-410A Puron. Reference: ...
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1answer
1k views

why does my heat pump wiring diagram show 7 wires going to the thermostat but the thermostat only says it needs 5?

Here is a link to the wiring diagram for my heat pump. The thermostat that I am planning on buying has the following terminals C, G, Y, O/B, RC, R, Aux, E, and L. The instructions say to jump the RC ...
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0answers
166 views

Why is my heat not shutting off at the set temperature?

When I turn the heat on on my central heat and air unit, the heat came on then continued to run getting really hot. It would not shut off unless I turned from auto to on then back. Sometimes I had to ...
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1answer
647 views

Do I need a sleeve for through the wall air conditioner in new construction?

I am about to buy a through the wall A/C unit for a small building, which the builder will frame out for the A/C. Is the framing enough, or do I need to buy a sleeve for A/C?
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1k views

Why would said gas furnace keep shutting off?

Seems that I have a gas furnace that is having some sort of heat/air sensing issue. Basically it shuts off after running for a minute or two. But if I remove the top plate of the furnace itself it ...
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0answers
214 views

Is it possible to insulate existing ducts without removing drywall?

My second story is always warmer in the summer and cooler in the winter than the ground floor. I've had the ducts cleaned and sealed and I've also adjusted the blower motor speed. It occurs to me that ...
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220 views

AC won't turn on after replacing thermostat batteries

we replaced the batteries on our thermostat after they began flashing for a few minutes. We'd been using the heater up to that point. After replacing the batteries, the heater does not turn on ...
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2answers
561 views

No electricity going to thermostat

Our old thermostat is working but I want to change to a new one (nest thermostat). I have two exact HVAC unit at home. I change one it works but when I change the second one it doesn't work because ...
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0answers
34 views

How can I determine if a valve complies to MSS?

How to know if the valve complies to Manufacturers Standardization Society (MSS) or not? I want to approve a valve for an HVAC project, but I don't know how.
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0answers
33 views

Is my heat pump's condenser fan motor bad? [duplicate]

The other day my AC stopped working. I'm thinking the condenser fan motor has gone bad (unit is ~10 years old). Here is what I did to troubleshoot which led me to believe it was the fan motor. ...
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1answer
2k views

How do I add a C/ Common wire to my “Specific” HVAC system? [duplicate]

I just bought a new WiFi thermostat that requires me to add a C-Wire at the furnace. I have read the questions related to my issue but would like a suggestion on my particular (incredibly OLD) ...
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1answer
571 views

How can I add a C-wire to a Venstar T5800 thermostat?

I am trying to replace my existing thermostat. My old thermostat has: Rh, W (coming from the heating unit). Rc, Y, G (coming from the AC unit). On the Venstar T5800, I can map as follows: Rh+Rc ...
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1answer
463 views

Why isn't my thermostat working?

I have an old Lennox (gas heat only) thermostat. There are 3 wires coming from the wall. Black, yellow and a light blue color (could be a faded green or an old dirty white). The thermostat wouldn't ...
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249 views

Why isn't water running through our radiators?

We had a plumber in today to bleed our rads. He also changed the batteries on the thermostat and fiddled around with the boiler. Since he left the temperature has dropped dramatically and he's refused ...
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0answers
84 views

I have no furnace, only electric blowing heaters. How do I get ventilation?

I have a 100 years old building with a store on the main floor. Since the building was built over 100 years old there is no ducting whatsoever. There is also no furnace. In the summer we just hook ...
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4answers
6k views

How can I use a separate transformer to provide a C wire to my thermostat?

I Purchased the Honeywell WiFi Prog Thermostat to replace my Round Digital Honeywell Thermostat. I have separate Heating and Cooling (Heating is a Weil McLain Boiler for Hot water baseboard and Hot ...
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2answers
367 views

Connection for range hood from 8“ circular to 10”x3.5" rectangular

I am installing a new range hood for our kitchen. The duct exhaust at the top is 8" circular, but our old vent to outside is 10"x3.5" rectangular. I see what we could usually use a register boot but ...
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1answer
62 views

When is a variable-speed compressor HVAC unit worth the cost?

Surprise, its summer and our AC broke down. We were quoted prices for installation of the current standard (SEER 14) AC units (about $6500 unit cost and installation) vs Trane's SEER 18 AC units ...
-1
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1answer
47 views

Why won't my electric furnace kick on unless the thermostat is set to 73?

I have an older, ill insulated mobile home. My house is obviously not 73 degrees, and my heater will not kick on. I set it to 73 and it finally came on, but then the furnace would not shut off. It ...
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1answer
48 views

What is wrong with my air conditioner

I have been using my air conditioner on and off all summer. The weather hasn't been really that bad this year. But now that the weather is reaching high 80s, my air conditioner decides to die on me. ...
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1answer
2k views

why won't my furnace turn off once it reaches the desired temperature

I have a moncrief furnace and replaced the thermostat but the furnace will not cut off once it reaches the desired temperature. What could be wrong?