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Questions tagged [central-air]

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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22 votes
4 answers
413k 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 ...
Doresoom's user avatar
  • 15.8k
11 votes
6 answers
2k 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 ...
Jeff Widmer's user avatar
  • 8,222
10 votes
7 answers
10k views

Why is my air conditioner causing rapid high CO2 levels?

I am wondering if anyone knows why when I turn my recently installed high-efficiency air conditioner on, CO2 levels rocket up in my house? (In just 4 hours they go from around 500ppm to 1200ppm, and ...
Adam Lopez's user avatar
9 votes
3 answers
7k 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 ...
Joel B's user avatar
  • 367
9 votes
5 answers
116k 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 ...
retracile's user avatar
  • 689
9 votes
7 answers
221k 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 ...
Jared's user avatar
  • 444
8 votes
3 answers
7k views

Convert GE Load Center to main breaker

I'm looking to add central A/C to my 1970s era home. The electric panel is a GE Load Center, 125 Amp max. It's basically "full" with no space for additional breakers. The bids for the electric panel "...
Mike Guth's user avatar
8 votes
3 answers
57k 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 ...
kbyrd's user avatar
  • 349
8 votes
1 answer
2k views

What causes burn marks on the air handler in the attic?

What caused these burn marks? Phoenix Arizona suburb. House was construction complete about 6 months ago. The tape and insulating foam around the bigger tube was cut. I assume the AC tech that ...
Kirkland's user avatar
  • 205
7 votes
8 answers
6k 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 ...
Engineer2021's user avatar
  • 3,315
7 votes
10 answers
6k views

Time to Replace Central AC?

Have a 2004, Rheem, Model #: RAMC-048JBZ; R-22 refrigerant. We live in Central Texas, very hot 5 months a year, we use the AC probably 7/8 months a year. Have had annual maintenance performed since ...
David H.'s user avatar
7 votes
3 answers
8k views

Should I install an air conditioner pad on existing unit?

In budgeting time and money for a house I just purchased, the inspector noted that the central air conditioner is mounted outside without a pad underneath. The unit is a Carrier 38CKC024330, ...
calcium3000's user avatar
6 votes
5 answers
1k views

Optimizing HVAC airflow for cooling

Here's the deal: Two-story c. 2000 house in southern Missouri, lower level is a "walk-out basement" (subterranean on 3 sides) and consistently 10 degrees colder then the main level year-...
Jamesfo's user avatar
  • 163
5 votes
2 answers
8k views

Can I just cut power to a central air and heating system, or should I follow a shutdown procedure?

I am going to install some NEST thermostats. The directions say that I should turn the system off by turning off the power to it. However, I'm worried that an abrupt power cut will be damaging. Do I ...
MonkeyBonkey's user avatar
  • 1,209
5 votes
2 answers
9k 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 ...
zk.'s user avatar
  • 433
5 votes
1 answer
859 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 ...
Evan's user avatar
  • 415
5 votes
2 answers
146 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 ...
Jackie Williams's user avatar
5 votes
2 answers
11k 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 ...
Jeff's user avatar
  • 323
5 votes
1 answer
11k 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 ...
longneck's user avatar
  • 21.3k
5 votes
1 answer
10k 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 ...
Doresoom's user avatar
  • 15.8k
4 votes
4 answers
1k 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 ...
qftme's user avatar
  • 141
4 votes
3 answers
49k 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 (80 °F+...
TomG's user avatar
  • 3,948
4 votes
4 answers
96k 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 ...
Vivian River's user avatar
4 votes
2 answers
3k views

Rust on outdoor ac fan motor? Tech recommends replacement?

I had my annual ac inspection. House has two units and one runs about twice as long each day as the other because it cools much more of the house, and had its capacitor fail two years ago. Tech ...
aggieNick02's user avatar
4 votes
1 answer
16k 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 ...
James H's user avatar
  • 278
4 votes
2 answers
5k views

HVAC is suddenly blowing room temperature air—compressor, fan still turn on

I intend to call a repair person, but I just want to make I've exhausted possibilities that don't involve messing with the refrigerant lines. The A/C was working yesterday with no problems (outdoor ...
Tahlor's user avatar
  • 187
4 votes
6 answers
210k 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 ...
stoj's user avatar
  • 299
4 votes
2 answers
5k 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 ...
Kyle Hayes's user avatar
4 votes
1 answer
13k 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 ...
ThaKidd KG5ORD's user avatar
4 votes
1 answer
600 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 ...
JavaKungFu's user avatar
3 votes
5 answers
3k 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 ...
blu's user avatar
  • 131
3 votes
2 answers
327 views

Central A/C system: compressor froze, refrigerant lines sweating through insulation, outside fan won't shut off

The story We noticed the outdoor AC unit was running (i.e., fan was spinning) nonstop for > 18 hours and was relatively louder than usual -- there is now a humming vibration that can be heard ...
theforestecologist's user avatar
3 votes
1 answer
219 views

What is a "solar-ready" air conditioner?

I've been looking into having solar panels installed. My understanding is that the solar panels connect to a breaker in the breaker panel, and so you have both the main breaker (from the power ...
user31708's user avatar
  • 235
3 votes
3 answers
37k 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 ...
Justin C's user avatar
  • 133
3 votes
3 answers
9k 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 ...
Howie Ross's user avatar
3 votes
1 answer
241 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?
Sam's user avatar
  • 165
3 votes
3 answers
6k views

Why doesn't my air conditioner's drip pan drain properly?

My AC Unit in my attic is roughly 10 years old, still heats/cools exactly as it should, but I noticed yesterday that the drip pan is overflowing. What do I need to do to get the drip pan to drain? ...
Smith Stanley's user avatar
3 votes
3 answers
138 views

Help diagnose a compressor problem

My fan on my A/C compressor unit seems to start and even spins up to a reasonable speed, although not quite the speed at which it ought to spin, but then 5 seconds later slows down to a very low speed ...
Wynne's user avatar
  • 1,541
3 votes
1 answer
3k 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 ...
Jay Prall's user avatar
  • 647
3 votes
1 answer
42k 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 ...
Zoomzoom's user avatar
  • 275
3 votes
2 answers
2k 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....
End Antisemitic Hate's user avatar
3 votes
1 answer
3k 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 ...
LasEspuelas's user avatar
3 votes
1 answer
292 views

High Power Bills Related to Air Conditioner

So I seem to be having trouble with my power bills (they've often been near $400 while other people in my area with a similar sized house usually get around $140), and I've isolated the issue to my ...
tearman's user avatar
  • 145
2 votes
3 answers
5k views

Do you remove an AC Capacitor from the circuit before or after you short it out for safety?

Is it safe to short (discharge) an AC capacitor before you remove it from the circuit. Or do you have to wait until after you remove it from the unit?
Evan Carroll's user avatar
2 votes
3 answers
9k 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 ...
DMoore's user avatar
  • 49.2k
2 votes
2 answers
934 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/...
Volvox's user avatar
  • 125
2 votes
3 answers
7k 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 ...
Aaron's user avatar
  • 21
2 votes
1 answer
2k views

Is it possible to adapt round HVAC diffusers to square?

I am working on a remodel in my older home. Currently all of the HVAC is run through sheet metal ceiling ducts, most of which are 8" diameter, and then when they reach the rooms, flair out to a ...
Jonathan Fry's user avatar
2 votes
1 answer
7k views

How to stop Central Air unit from freezing over inside and outside

Today I noticed the AC wasn't working. I checked the unit outside and saw the line freezing. I checked inside and it's frozen as well. I turned the AC off and fan on. The ice is melting now. I ...
Philip Rego's user avatar
2 votes
1 answer
213 views

Tolerance for LRA and other settings on my AC unit from those on the nameplate?

tl;dr - How close to the compressor LRA / RLA and fan motor FLA should the meter readings be compared to the values on the plate? Do you also need to consider if multiple readings are off or too far ...
HelpEric's user avatar
  • 631

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