Questions tagged [hvac]

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

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4
votes
3answers
82k views

How can I prevent my house from smelling of smoke after having a fire in my fireplace?

We have a wood-burning fireplace in our family room. Fifteen feet from the fireplace is a large cold air return. When the fireplace is stoked, nice and cozy, everything is fantastic. When I shut it ...
3
votes
6answers
34k views

Air handler condensation draining problem

For the life of me, I cannot figure this out. My air handler and heat pump were installed in 2006 and work great. For the first summer since I've owned the home, condensation started to not drain ...
3
votes
2answers
10k views

How do I replace a condenser fan motor in a central air unit?

The condenser fan motor on my central air unit has seized up (tried like crazy to turn it it, but no go). I'm not sure how old the motor is but I'm guessing it's original, so about 12 years old. I ...
3
votes
2answers
1k views

Can I use an unused wire as a “C” wire?

I just bought a new thermostat that is Wi-Fi enabled and it requires connection to a "C" wire. The old thermostat does not have one running to it, but there are other unused wires. The thermostat ...
3
votes
6answers
11k views

How can I vent a portable air conditioner when there's no window?

My shop does not have central air and does not have operable windows. There is a steel door in the back and cinderblock walls. My landlord is against me cutting a venting hole in either the steel ...
3
votes
2answers
2k views

How can I prevent my clothes dryer door from fogging up?

When I turn the air conditioning on in my house, the inside of the window in the clothes dryer door fogs up. Also, if clothes are left in the dryer, they become slightly damp again. How can I prevent ...
3
votes
1answer
2k views

Is it necessary to discharge the capacitors on an AC condensor?

I intend to replace the capacitors on my house air conditioner condenser. This video claims that discharging the capacitors is not necessary, because the circuitry will discharge through the fan ...
2
votes
1answer
5k views

What could cause a replacement A/C condenser fan motor to only run for 3 minutes?

Just replaced a GE 5KCP39FG Condenser fan motor with an AC Smith FSE1026SF. HVAC Counter sales told me it was the right one and gave me a Partners Choice Capacitor 01-0085 to match. Old motor 3 ...
2
votes
2answers
2k views

Best way to insulate sweaty sheet metal ducts in unconditioned space?

My air return system is in a small closet in my garage. When I run the A/C when it's hot and humid out, the ducts sweat and drip a lot of water onto the wood platform that the HVAC and water heater ...
2
votes
2answers
2k views

Is it safe to replace a Furnace pressure switch with a different one?

So I had some problem with my gas furnace and a technician came by to install a new one but it doesn't have the same rating and only has one tube instead of two. He assures me it's fine but I thought ...
2
votes
2answers
43k views

AC Unit Blow Warm Air Indoor But Colder Air Outdoor

I have two AC Units. One for upstairs and one for downstairs. The upstairs one works just fine but not the downstairs. So, i did a test by turning both units on and went outside to compare the two ...
2
votes
3answers
7k views

Furnace runs for about 5-minutes only and shuts off

Furnace (Lennox G40UH, 12 years old) runs for about 5-minutes (sometimes as high as 7-minutes) and they turns off despite the heating call from the thermostat continuing. Flame sensor has been ...
2
votes
2answers
305 views

How can I get better HVAC airflow?

I recently purchased my house which was a new construction. Several of the vents are getting poor airflow but the installation company simply said it was normal but I suspect otherwise. I recently ...
2
votes
1answer
11k views

Why won't my Heil 7000 natural gas furnace ignite?

I have a Heil 7000 gas furnace Model: NUGK100DH12 Serial: L933050100 When we turn it on at the thermostat, the exhaust blower will kick on. We checked to be sure the gas is reaching the unit and ...
1
vote
1answer
162 views

How do I install a high intensity infrared heater and thermostat

I picked up an old Lambert L-40 high intensity infrared gas heater but it didn’t have a thermostat. I can’t find any info about this heater online and I am hoping someone on here can help. I ...
1
vote
5answers
67 views

How to size a whole house fan?

I'm in the middle of a home addition and am thinking about adding a whole house fan. The finished size of the house will be about 2000 square feet - approx 1500 on the main level, and 500 on a lower ...
1
vote
1answer
31 views

A.c. fan outside not coming on

It started with the thermostat not going in on only fan. That night i go to turn the AC on and the condenser fan wouldn't come on so I took a stick moved the blades and it started . i thought its the ...
1
vote
2answers
9k views

How do I connect a dryer to a dryer vent?

I just moved my dryer (gas) a couple feet to a better location in the basement. It is actually now closer to the existing dryer vent to the outside of the house. The previous owner has it connected ...
1
vote
2answers
352 views

Must my new air conditioning unit be 3 feet from the wall (or positioned backward)?

My contractor installed this system yesterday, at my property: "Trane T4TTR6060C1000A RX16 5 TON XR16 A/C 16 SEER rating R410A". Everything is working fine. I just do not like aesthetically how he ...
1
vote
1answer
35 views

New primary control switch problems

About a week ago , I had someone to come in and replace my old RA116 stack switch with a Honeywell R8184G oil primary , for the first day it was fine, next thing I know the furnace turned off and ...
1
vote
2answers
1k views

Where do I attach C-Wire in this old Rheem Air Handler

Trying to attach a c-wire to old rheem air handler for a cooling system only. System is so old I didn't see what I thought I'd see when I got up into the attic. In going over the pictures I think I ...
1
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4answers
9k views

Are there efficient ways to provide combustion air to heating appliances?

In a previous question we established that there probably should be a vent between my utility room (which opens into the kitchen and living space in general) and the outdoors (in my case the attic, ...
1
vote
1answer
148 views

Can dehumidification be achieved in a typical US residential forced-air system without dedicated components?

We have a very typical forced-air HVAC system with a medium-efficiency gas furnace and split-system central air conditioner in our house; however, latent load buildup (i.e. stickiness) is a problem ...
1
vote
0answers
588 views

Adding a C wire

I know this question has been asked multiple times and I'm going to try some of the methods I have read in other threads but wanted to ask this question since I didn't see anyone else's wired the way ...
1
vote
2answers
114 views

Is there some type of coating I can use to prevent condensate on my HVAC ducts?

I'm getting a lot of condensate on my HVAC ducts that run though my first floor (and HVAC blower) especially in July / August when humidity levels are outrageous (in NJ). The 1st floor space space is ...
1
vote
3answers
16k views

A/C not keeping up

So, the first warm-ish day of summer finally showed up in the Black Hills yesterday and I noticed that our central air conditioning was not really keeping up... the thermostat was set at 72, but the ...
1
vote
2answers
50 views

Airflow question

If I setup a 1200 cfm extractor on a basement room, and it will be turned on 24/7 to cool off some computers will the air of the entire house also be extracted? and cause the HVAC system to work ...
1
vote
2answers
3k views

New condenser fan motor burned out

AC technician replaced my condenser fan (through a home warranty service). The new fan worked for 5 min and stopped working after that. the fan motor was extremely hot (180F or more) The old fan motor ...
0
votes
1answer
9k views

Quieting cold air return vent

My gas furnace is in a dedicated "closet" inside the utility room. The closest cold air return is about 5' away (laterally) in the ceiling of the hallway right by the bedrooms. When the furnace ...
0
votes
0answers
39 views

Indoor blower fan turns on and off intermittently in 10-15 min increments when system is off. [duplicate]

Bit of background: The furnace blower originally did not not turn off at all (or if it did, very rarely did so), even when set temps were reached or when the system was off (fan setting is set to auto,...
0
votes
1answer
1k views

How to connect a DIY thermostat to the HVAC System

I am building a DIY thermostat similar to this blog. I want to connect it to the HVAC system of my home. How do I do that? I found this post which is very informative but doesn't completely answer my ...
0
votes
1answer
876 views

What is this fabric tape made out of?

Any ideas what is this fabric tape on my cool air return ductwork? High res close-up Some of it is separating or worse falling off of the duct work on the cool air return to my forced-air gas ...
0
votes
1answer
599 views

How can I plug a hole cut in a window pane for a portable A/C unit?

I just moved into a room where there is a portable A/C unit. To create a vent for the unit, a hole was cut in the glass of one of the window panes that spans about 13.5 cm. I was told that the unit ...
0
votes
3answers
6k views

Do I really need 10 AWG wire for a AC condenser that says 15 AMP max?

I'm buying a used AC condenser for a rental property. The unit says max amps = 15 (see below), however the HVAC guy tells me I want a 20AMP double pole breaker with 10 AWG? I would have though 15 AMP ...
0
votes
1answer
674 views

How long should it take to a 1.5 tons AC to cool down a 2000sqf house from 80F to 77F?

I know that it might depend on a lot of things like: -how air tight is the house -how old it is (insulation, windows etc) -what windows are installed -BTW I have casement window -outdoor temp (...
0
votes
1answer
1k views

What type of dryer best handles long exhaust vents?

I have a very long exhaust line (about 5 meters) from the dryer and have issues with moisture staying in it when I do laundry. Since the old dryer broke down, I am now shopping around for a new dryer ...
0
votes
1answer
2k views

Duct static pressure vs ambient air pressure

I've read that air handlers are typically rated for 0.5 iwc. Doing a simple conversion, this comes out to about 125 Pa. Is this with reference to the ambient air pressure? So, if I had an absolute ...