For questions regarding a central cooling system for your home. This is typically a split system with an outdoor compressor/condenser and an indoor evaporator and air handler. Air ducts are used to cool air throughout the home.

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1answer
26 views

Difference in total pressure when HVAC system is on or off

This is a follow up question to one that I asked here. I am measuring the total pressure at the registers (all registers are open) with the BMP180 pressure sensor and somehow they don't change very ...
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0answers
19 views

Does an outdoor AC condenser unit (Heat Pump) require lubrication? Pic included

I have been in my house for 11 years now and every 3 or 4 years I have been taking the lid off my condenser unit and lubricating it. I just don’t know if I am even supposed to do this, but it make ...
11
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4answers
113k views

What's the most common cause of A/C refrigerant lines freezing?

I noticed my house wasn't getting under 75°F this weekend when I had the thermostat set for 70°F. Since I'd done a lot of drywall sanding inside recently, my first idea was to replace the filthy air ...
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0answers
11 views

How to fix uneven central heating and air?

My central heating and air conditioning system does not heat my home evenly. Half of the house gets significantly warmer / cooler than the other half. I have tried adjusting the registers, but to no ...
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0answers
21 views

Quiet Ceiling Registers?

Our new central AC has a powerful fan because it sounds like a hurricane coming out of the bedroom ceiling registers. They're 14.5" x 14.5" edge to edge (so I'm guessing the actual opening is 12" x ...
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2answers
1k views

What can cause an A/C to freeze up

Our A/C evaporator coil freeze up last year, so I called out a technician. He said that it was charged with the proper amount of Freon, and my problem [paraphrased] "something had narrowed the inside ...
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1answer
39 views

internal fuse on air handler blows every time it shuts off

air handler for air conditioner has worked fine since I moved into the house but this year both times the air conditioner has turned on it has not restarted. Both times so far the problem has been ...
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2answers
1k views

Should I move the furnace upstairs to help cool the 2nd story?

My wife and I live in a two story, 1400 sqft home. Recently, our 24 year old HVAC system died on us and we've been recommended by three different independent repair guys to replace the system rather ...
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2answers
4k views

What to do about different rooms in the house being a completely different temperature?

I moved into a 30 year old home last December. There is a problem with the HVAC. I have included a very crude drawing of the floor plan The problem is that I can't maintain a comfortable ...
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1answer
67 views

How to determine if my heating & cooling system is adequate for my home?

Is there some kind of calculation I can follow to determine if the heating and cooling system in my home is rated (adequate) for the size of the house? I assume there is some way to say something ...
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0answers
30 views

What to look for in central air installation?

I'm having an HVAC company install a York central air unit in my house today, and I'm wondering what things I should be looking for in the quality of the installation? Existing York central heating ...
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2answers
105 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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0answers
25 views

Why does the A/C come on downstairs when heat is on?

I just moved in to a 2-story house. It is zoned upstairs and downstairs. If I turn the downstairs thermostat to OFF and the upstairs to COOL, the HVAC in the attic comes on, the outside compressor ...
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1answer
60 views

What is causing my AC to trip the breaker after running for about an hour?

After I turn on my ac, about an hour or two later it will make a noise and trip the breaker. Could this be a short in my fan motor? The fan does run.
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0answers
26 views

Buying used heat pump/AC

I'm planning to buy and install a used heat pump/AC at some point in the near future (probably looking for sellers on Craigslist or similar), and want to know what I should look for to know if the ...
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1answer
182 views

Central Air duct does not blow

We moved into a new house last year, the central A/C works great for all the rooms (even for closet) but we have a problem in just one room. There is almost no air flow coming from that room's air ...
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1answer
303 views

Air Conditioner woes: water pooling in basement, condensation on ducts, frost on outdoor copper pipe

Can someone help diagnose what's wrong with my air conditioner? The symptoms are: the air that it is blowing is not very cold It's colder than the ambient air, but not cold enough to cool the ...
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5answers
14k views

What could be causing an A/C blower motor to turn off randomly?

The Blower motor on my AC unit turns off at random times while the outside unit continues to run which is causing the coil to freeze up. The blower won't come on for 30-45 minutes after the AC has ...
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1answer
69 views

Is this HVAC capacitor dead?

HVAC system stopped blowing cold air today. Last time it did this, we gave it a 2-3 hour break, in case it was over-heated, and it came back. Today, same deal, but no cold air after a few hours. I ...
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5answers
14k views

How much cooling can I expect from a central air conditioner?

Yesterday's high was 106.0F, low of 79.2F, full sun all day. AC set at 78F, indoor temperature reached about 85F. Today's high was 105.4F, low of 81.1F, full sun all day, now about 102 at 7pm. AC ...
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1answer
69 views

Replace reusable air filter with disposable, when no size matches?

My friend's house has HVAC whose air filter is a rectangular metal frame filled with washable fiber mesh. It doesn't look like it could catch fine particles. We wanted to try an off-the-shelf ...
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2answers
192 views

How do I interpret a central air conditioner label?

The label on my central air conditioner looks a lot like this one (photo below). What do the two numbers (separated by a slash) mean for voltage and the three amperage ratings?
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1answer
241 views

Central air conditioner grounding wire size difference

I disconnected the central air conditioner long ago during the initial phase of my home renovation. I am preparing to hook it up again and have a technician come out to look at it. The original wire ...
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2answers
179 views

What size A/C unit should I install?

currently using a Goodman 24000 BTU Central air, installed in '96. it is starting to cost too much because of leakage of refrigerant. I did the size calculator thing and it recommends a 30000 BTU ...
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1answer
984 views

New Central Air Install: choosing single-stage vs dual-stage condensers

Specifically: would a 2-stage 3-ton condenser be more efficient than a 1-stage 2-ton condenser? Let's assume the same SEER rating for both. What about reliability? - I heard that 2-stage are a lot ...
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1answer
1k views

How should I evaluate my central A/C to see if it's working properly?

I was once told by a service tech that they evaluate how well the system is performing based on temperature difference between the the return and supply sides. On our first really warm day (80F+), I ...
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0answers
103 views

How to insulate this portion of split AC Pipe?

I bought a new Hitachi split AC lately which isn't cooling as much I was expecting. I checked for leaks/bad installation and found this. (This is connection point of external pipe and pipe which ...
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1answer
81 views

Central air compressor fan reflects sunlight into house. What can I do about it?

I have a new construction and for whatever reason the HVAC installers placed the compressor right in front of a bedroom window. I don't have any complaints about the noise (it is actually pretty ...
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1answer
1k views

What causes a HVAC control transformer to overheat?

I recently replaced my 24 volt HVAC control transformer. The outside unit started up including the air handler and ran for maybe 10 minutes. After the units shut down I noticed that the transformer ...
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4answers
816 views

What type of regular maintenance should I be doing on my central air conditioning unit?

I have not done any maintenance on my central air conditioning system since I bought my house five years ago. Everything seems to be running fine but is there some sort of maintenance I should be ...
4
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5answers
29k views

Should I insulate air conditioner coolant pipes?

I recently replaced some rotted insulation on the coolant pipe that runs out of my AC unit and into the evaporator in my house. When cleaning inside the actual AC unit itself I noticed that the ...
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0answers
59 views

Are wall air vents a potential problem?

A house I'm looking at has A/C vents in the walls, rather than in the ceiling or floor. I've never lived in a house with air ducts in the walls. Can I expect to have problems? The house was built in ...
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2answers
5k views

Why are almost all of my house's HVAC floor registers placed near exterior windows?

My current house is a single story built over a crawlspace and all the HVAC registers are in the floor. In all of the larger rooms, at least one (and usually more) register was placed near an exterior ...
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1answer
1k views

When should HVAC returns be opened and closed?

My Pennsylvania house was built in the early 90s, has central heat (natural gas) and central A/C, and most rooms have pairs of closable air returns on the wall near the floor and ceiling. I've been ...
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1answer
4k views

How do I eliminate the cold drafts coming from my air conditioning vents during winter?

I have a forced hot water (baseboard) heating system in my home and added central air conditioning about 10 years ago. The cooling system's air handler is in my attic, and duct work was added for the ...
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1answer
1k views

Why is my outdoor air conditioner unit making a screeching/squeeling sound?

During the winter time when I have my heat on, my outdoor air conditioner unit randomly makes this awful-sounding squealing/screeching sound. It lasts for about 15-30 seconds at a time, stops, and ...
3
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1answer
3k views

Where should I tap in to the existing duct work?

Bought a 1981 repo a year ago. The house measures around 900 SQFT. I enclosed the one car garage (10'x20') @ 200 SQFT to serve as an office. The front of the garage is insulated (10') along with the ...
2
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1answer
336 views

Why do they put an A/C vent in the utility room?

A related question is here about a year ago: Is there any reason to not tape this vent over? My question is, why do they put the vent there in the first place. Like the previous poster, I just bought ...
5
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1answer
952 views

How can I replace the plywood under my air handler?

Sunday morning I walked out into my garage to find two huge water spots in the ceiling. The condensate drain line that comes out of my air handler in the attic had clogged up, and it turns out the ...
2
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2answers
1k views

What is going on with my central air?

I have a re-occurring issue with my central air. I have changed filters, cleaned all three intake vents and even had a serviceman out on three different occasions (two separate companies). My problem ...
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2answers
1k views

What could be causing this leaky evaporator problem?

My apologizes if I do not know the correct terminology for some of the parts. I will try my best though. We have a Trane A/C system that is causing us a headache. It is causing water damage in our ...
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2answers
5k views

What should I do about a central air duct leaking above my ceiling?

My closet ceiling is leaking a brown liquid. Right above it is an air duct for my central air. I think the liquid is dirty or rusty water that has accumulated in the duct. I can hear it dripping ...
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3answers
1k views

How can I repair these rusty electrical connections?

When I turn on my air conditioner at the thermostat the vents kick on but nothing outside. Also the last time that it worked it took a few minutes to get going and was pretty loud. I checked the ...
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7answers
1k views

Should I apply car wax to the outside of my air conditioning unit?

Through different conversations with family members and friends, I have been told that it is good to apply a coat of car wax to the outside of the air conditioning unit frame. I assume that this is to ...
3
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4answers
473 views

Air conditioning on a shoestring budget

Without purchasing expensive air-con units, or solar panels - and the associated moutings and electrical paraphernalia, is it possible to create a temperature difference of 10-20 °C using materials ...
3
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1answer
303 views

Is it normal for air to be leaking from where the drain hose connects to the central A/C unit?

I'm trying to determine if I have a leak around my central AC unit. Basically when the unit is on, I feel cool air blowing outside the "furnace plenum" as I believe its called. If you look at this ...
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1answer
625 views

Is there any reason to not tape this vent over?

I just want to make sure this wont hurt anything. Right before I bought this house, it got a new AC and furnace but they did not replace much of the duct work. This vent is right above the AC unit ...
3
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2answers
360 views

Are clogs in the AC condensate drain common in Florida?

I have a two year old central A/C unit. Every 2/3 months the unit shuts off. I called the rep/maintenance company and they have given me the following response: The cause of the issue is algae ...
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3answers
1k views

Should a bathroom fan vent to a separate duct system?

Is it acceptable to route a bathroom exhaust fan to the return of a central air system? I'm afraid this will cause mold to grow in the air return ducts. There is currently a fan in our bathroom and ...
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0answers
848 views

A/C system reports Limit Switch Stuck Open

Unit is a York GM9S080B12UP11G. When switching thermostat to cool, the system activates the compressor fan. Also, I can hear gases moving through the pipes running to the compressor. However, the ...