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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14
votes
4answers
241k 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 ...
9
votes
6answers
1k 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 ...
8
votes
3answers
2k 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 ...
7
votes
5answers
48k 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 ...
7
votes
2answers
12k 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 ...
6
votes
7answers
2k 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 ...
5
votes
1answer
327 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 ...
5
votes
2answers
76 views

Can I install A/C in a home built in 1924 which has round heat ducts in the ceiling?

Can I install A/C in a home built in 1924 which has round heat ducts in the ceiling? I am looking at homes to purchase in Milwaukee, WI. The home seems to have all it's ductwork above the ceiling, as ...
5
votes
1answer
2k views

two condensate drains?

we just had a new AC system installed in my florida house. the unit is in the garage, and the air handler is vertical with the evaporator on top. the unit he removed had 2 condensate lines: one that ...
5
votes
1answer
2k 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 ...
4
votes
2answers
2k 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 ...
4
votes
2answers
7k 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 ...
4
votes
7answers
62k 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 ...
3
votes
4answers
642 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
votes
2answers
460 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 ...
3
votes
2answers
110 views

Continued Excessive dust in home air

I'm having minor breathing issues and suspect the home air quality, which seems to be excessively full of particles/dust. The air quality is visually noticeable daily, regardless of basic cleaning/...
3
votes
1answer
6k views

Air deflectors on floor registers and cooling efficiency

I was once told by an HVAC technician to avoid using air deflectors on floor registers during the summer. The reason was that the last thing you want to do is to direct the heavier, colder air ...
3
votes
1answer
223 views

Improve AC flow to secondary ducts

I have an AC which has 3 ducts coming out of it. Only one duct gets flow - I'm guessing the AC fan blows right into it. What can I do to improve the flow?
3
votes
6answers
49k 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 ...
3
votes
1answer
81 views

open cinder block wall in basement

I am replacing some framing and sheet rock that has been contaminated by mice. The basement has cinder block walls that come up about half way for some reason. The house was built in the 1950s. In ...
3
votes
2answers
524 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 vents....
3
votes
1answer
6k 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 ...
3
votes
1answer
384 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 ...
2
votes
3answers
3k 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 ...
2
votes
1answer
1k 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 ...
2
votes
3answers
4k 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 ...
2
votes
2answers
13k 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 ...
2
votes
4answers
30k 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 ...
2
votes
3answers
9k views

How do I eliminate stagnant water caused by central A/C draining outside?

So I just moved into a new house in NC that I am renting. The house has central A/C which is great, but because there is no basement so there is no basement drain. So the A/C expels the water into the ...
2
votes
2answers
2k views

How do I clean an AC condensate pan?

I have a Ducane HVAC system that started leaking out of the evaporator coil housing. Mine looks like the EU1P. I read that i need to clean out the drip pan. II tried cleaning it by sucking out the ...
2
votes
2answers
3k 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 ...
2
votes
1answer
482 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 ...
2
votes
2answers
8k views

AC unit won't turn on: both inside blower fan and outside fan unit won't turn on

AC unit won't turn on: both inside blower fan and outside fan unit won't turn on. It is as if I had gone to the circuit breaker and cut the power to the whole HVAC system, but I didn't. I've been ...
1
vote
2answers
318 views

Breaker lets more Amps then its max

The last few day's I had the main breaker triped a few times, I checked the amps with a multimeter and when the central air conditioner turns on it draws 150! amps for 1 second and then goes down to ...
1
vote
2answers
108 views

What leaked out of small copper line when I blew a hole in on my air handler

I changed my blower motor out and in the process a wire arced out on a small copper line and blew a hole in it. What leaked out? I have since soldered up the hole and have not run the unit. I fear ...
1
vote
2answers
1k 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?
1
vote
1answer
92 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
95 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 ...
1
vote
1answer
9k 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 ...
1
vote
1answer
33 views

My AC unit won't blow cold

So, I was changing a light switch and flipping circuit breakers to find the correct one. I accidentally flipped my AC circuit breaker off and then back on. After this I noticed the AC wasn't blowing ...
1
vote
2answers
60 views

A/C tune-up: “Condenser fan motor drawing high amperage”

A local A/C company was offering a deal on a home heating/cooling "check-up". I've never worked with this particular company before, and I've had some bad experiences in the past (different home, ...
1
vote
1answer
266 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 ...
1
vote
1answer
285 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 ...
1
vote
3answers
3k 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 ...
1
vote
1answer
2k 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 ...
1
vote
1answer
662 views

Furnace Airflow

I have central air. When the furnace comes on, we can feel air coming out of the registers for a few minutes, then the airflow stops. If we turn it off for a few hours, we can turn it on again and get ...
1
vote
1answer
34 views

Repairing Leak in Refrigerant Lines

We recently found and pinpointed a leak in my copper refrigerant line (the non-insulated line) and was wondering if there was anyway to repair and replace that one spot on the line (like if there were ...
1
vote
1answer
357 views

Home: Using Exhaust & Circulating Fans to Improve Air Quality While Staying Cool

In the hopes of ventilating nasty odors and airborne contaminants, I recently installed the Bionaire BW2300 in one of my kitchen windows. This is the only one I have installed in my home at the moment....
1
vote
1answer
176 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.
1
vote
2answers
6k 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 ...