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

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1answer
484 views

Why does the blower in the attic vibrate during heating when it is really cold?

We have a Carrier heat pump system in our home, and the blower is located in the attic. When it is especially cold, the blower runs on high (there are three levels: high, medium, low). During this ...
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0answers
1k views

How can I tell if my bathroom ceiling vent is working properly?

Seems to take the vent forever to clear shower vapor from room. I purchased a vent that had a good rating. It is vented to the outside. How do I know if it is working properly and actually venting to ...
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1answer
604 views

Can I connect two separate ducts systems together?

My apartment, which I own, is split upstairs by two hallways. Each hallway has its own A/C unit, to cool 6 single person rooms each. Recently the south side A/C broke. I have called the repairmen out ...
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2k views

Reducing air conditioner compressor vibration noise

I have a two year old Carrier air conditioner with an outdoor condenser. The condenser sits on a plastic pad on the side of my house, and I have two--one for downstairs and one for upstairs. ...
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0answers
91 views

How do I troubleshoot my central A/C?

It's 79 outside right now. It's been running for hours and it's remaining 79 inside. I'm in a brand new 2 story home in Monroe, OH. It has rained a lot recently but I just feel like it should be ...
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100 views

Why doesn't my A/C get power when using the alternate C-wire thermostat hook-up method?

I changed my old Honeywell thermostat for a new Honeywell WiFi thermostat. I installed it just as the directions stated. I used the alternate C-wire method as the old unit did not have one. ...
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3k views

How do I size a wall sleeve for a through-the-wall air conditioner?

We are shopping for a through-the-wall air conditioner. We do not currently have a hole in the wall with a sleeve in it. We are trying to figure out what sleeve to buy. The air conditioner we like ...
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0answers
3k 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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57 views

How can I add a common “C” wire to my thermostat? [duplicate]

Possible Duplicate: Options for adding ā€œCā€ wire to thermostat I recently bought the Honeywell THM5320R Wireless thermostat. After going to hook it up I found what many others have, it ...
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0answers
1k views

How can I properly drain heatpump condensate?

I have a heat pump in the attic That drains to the ground outside two floors below. I naively added a hose fitting so I could redirect the water where I wanted it, slightly up hill. This created a ...
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3answers
92 views

Furnace turns off power to the thermostat

When my natural gas furnace is running for a while and it gets too hot, the limit switch turns off the burner. When it does this, the power also gets cut to my thermostat. This causes the thermostat ...
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1answer
2k views

How to connect Nest in Europe

I found a question regarding the Nest thermostat here. But that is only a question "Will it work?". Thanks to that I know it WILL, the problem is...HOW. I know the wire naming conventions are ...
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2answers
17k views

Is it normal for the A/C to be dripping from top pvc that's coming from attic?

I thought I remember being told that water should drip (condensation) from the bottom pvc that comes out of the house but it should never drip from the top pvc. I thought he told me that if it ...
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1answer
271 views

Can you vent electric dryer into furnace return?

I've got an electric dryer currently vented outside: Behind the door to the right is our heat pump furnace: I was thinking about, during the winter, venting the dryer (properly filtered for lint) ...
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3answers
27 views

Mount horizontal 6" metal exhaust pipe to wall economically?

I'm trying to add more ventilation to the back room of my garage. The only available outside air exit location is 25' horizontally along the front room of the garage's wall. I have 6" 30ga sheet ...
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2answers
52 views

reclaiming exhaust from 'on demand water heater'

Is there some way to recover the heat which is lost through the exhaust system from a 'on demand water heater' ?
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4answers
2k views

HVAC supply vent noise: how to eliminate the whistling wind tunnel?

Every time the heat turns on (rented house), we are getting choked with too much dry hot air in our small room. When I try to close the supply vent it produces a really loud whistling noise. I either ...
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2answers
199 views

Home inspection requires exhaust to attic exterior

We have sold our 1995 built home. One item that needs to be addressed is "Bathroom fans vent to attic and need to exhaust to the exterior of the attic to prevent moisture condensation in attic." I ...
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1answer
41 views

Water dripping out of small pvc pipe in soffit of house

Yesterday was an extremely hot day here in SoCal with temperatures around 100F. The AC unit had been turned off during the daytime and at nighttime we turned it on to cool down the house. A few ...
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3answers
43 views

Cooling radiators in summer?

How efficient would it be to use radiators circulating with cold water, to cool house in summer? Wondering if anyone has tried this, and how well it works? I was thinking about H/AC in general, and ...
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3answers
96 views

What steps are needed before brazing attic a/c copper tubing with a leak?

Yesterday I discovered water stains on one of the air ducts in my house. I went up the attic and saw that a copper pipe cool to the touch which seems to be linked to the condenser? had a pin point ...
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3answers
168 views

One portable air conditioner - want to use it in two rooms

I have a Kenmore portable air conditioner model - 408.72012. this particular model can be housed on the outside of the building and the A/C air is vented into the inside space (normally through a ...
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1answer
673 views

Can I fill this AC line inlet with expanding foam?

I think the PVC inlet for my AC lines is a possible entryway for mice getting into my attic. Is there any reason I shouldn't fill it with expanding foam to seal it off? Or is there a better, less ...
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1answer
2k 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 ...
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1answer
62 views

AC Condenser Fan Won't Spin and Overheats But Can Be Kickstarted

Symptoms: AC kicks on, but blows warm air Found issues: AC kicks on and AC condenser appears to turn on (makes noise), but the fan won't spin. A few seconds later, the condenser fan motor overheats (...
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1answer
32 views

Electrical Disconnects for condensing unit

What year did the NEC code require electrical disconnects to be installed at HVAC condensing unit?
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3answers
421 views

What is the correct way to seal/flash coolant lines through T1-11 siding?

Our contractor installed an AC compressor and did a poor job of it. He ran the AC coolant lines through the middle of the wall and then just squirted some expanding foam into the hole, like so: (...
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1answer
62 views

Furnace Fuse Blows Immediately

This afternoon, our Ruud furnace suddenly stopped working. After poking around a bit, I realized that the 3A fuse on the control board had blown. I ran to the hardware store and replaced it, but no ...
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1answer
100 views

Downsides to staple up radiant heat, besides cost?

I'm considering doing a radiant heat retrofit into my home and removing an older forced air system. The plumber is proposing a staple up from the basement into aluminum plates with PEX tubing with a ...
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3answers
158 views

Problem- air condition- compressor and fan outside not on

I'm new to hvac. My ac was working fine but it decided to die one day. I've been able to fix my ac, but it continues to happen(the same problem), and it is not easy to get to the ac (it's on the roof)....
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3answers
96 views

Ac unit set on 74

My central air is set at 74. Yesterday and today, the house was up to 80. It has been very hot outside(90). Would this affect my ac unit?
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264 views

Do I need a neutral wire when connecting a 240V device?

So this is still not very clear to me: I am trying to get 240V to an appliance that does not need a plug (direct wiring), I won't need a neutral wire, is this right? In fact there is nowhere to ...
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1answer
602 views

air conditioning system stays on even when we turn off our thermostat

Our A/C system stays on even when we turn off our thermostat. What should we do to try to fix it?
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3answers
152 views

Will high efficiency furnace plumbing lead to cold air entering the house?

At the outside wall of my house I can see two white PVC round tubes/pipes, I understand one is for sucking air from outside, and one is for furnace blowing warm air to outside - correct? We are ...
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2answers
308 views

how do I keep leaves and foreign objects out of the top of my a/c unit?

Is it possible to make a lid that is light enough for the air coming off the fan to raise it attached with hinges so it drops back down when not in use. This would keep debris from getting inside, yet ...
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1answer
564 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 ...
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1answer
553 views

Exhaust venting into air return?

In the condo (2 story semi-detached townhouse built in 2004) I rent, the main bathroom has an interesting vent system. When turned on, 2 fans are activated. One is a booster of some type and ...
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1answer
488 views

Why do I have a large PVC pipe venting warm air outside intermittently?

There is a large PVC pipe (3 actually) which vent air intermittently. I started noticing I could see steam rising over my deck in the morning and then I found that these pipes vent air at least a ...
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2answers
56 views

How to move from RH/RC thermostat to C thermostat in AC only system?

I see this is a pretty common question, but the answer seems like it might be dependent on your thermostat and air handler, so I'm posting with my specific questions. I'm upgrading from a White ...
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3answers
124 views

How to recharge a window unit air conditioner?

Can I recharge my window unit air conditioner or do I have to send it to a specialist? The AC unit that I have is about 15 years old (nothing lasts forever)... and I happen to have about 20 lbs of ...
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101 views

In what circumstances would an AC produce no condensate but still cool the air?

In what circumstances would an AC produce no condensate but still cool the air?
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1answer
41 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 (...
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1answer
24 views

Are HVAC Transformers Interchangable (if their power ratings match)

I'm troubleshooting the blower not starting in a friend's HVAC system. We think the issue is either a) a blown transformer, or b) the relay that controls the blower has blown. The next step is to ...
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1answer
46 views

How do I wire my old 3/4hp 115-120v 50-60Hz HVAC motor to make an exhaust fan?

My old HVAC blower motor has the following wires and I would like to know how to wire them to a typical 110v plug for use as a garage exhaust fan. yellow (N) black (L) yellow/green (ground) black (M1) ...
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2answers
58 views

How do RH/RC/R and Y/W relate for HVAC?

I have the following notes for HVAC (that I've compiled from reading through here): Thermostat wiring: C low voltage power wire that brings power from heating/cooling equipment to thermostat ...
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1answer
51 views

Does it take long time to turn AC unit around?

I am wondering if it can take a full day of work to turn around AC unit like in this post . Must my new air conditioning unit be 3 feet from the wall (or positioned backward)?
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39 views

Does thermostat need to be grounded?

If a thermostat is connected to an air handler, which is connected to the main panel and has a ground wire, should one of the thermostat wires be connected to the ground?
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42 views

Is there a way to measure the output of a single HVAC vent?

As inspired by this previous question, is there a method or device used to measure the output of a single HVAC vent or the output of a single room? I'm imagining some sort of hood device that could ...
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1answer
52 views

Pilot lights, but main burners don't on furnace with no flame sensor

I have a Rheem furnace in my house. It recently stopped working. It is the type where the pilot is not always on. Anyways, the ignition will kick in, and the pilot lights just fine. However, the ...
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1answer
159 views

Air Conditioning Drain Pump

I am going to purchase Multi-Split air conditioning unit for my apartment that I am fully renovating at the moment. So it is the right time to make wholes in the walls etc. The supplier is giving an ...