Air Conditioning Troubleshooting & Diagnosis FAQs (list of frequently asked questions about air conditioners)

These questions & answers about fixing problems with air conditioners & heat pumps were posted originally on the air conditioning & heat pump home page.

Typical air conditioner concerns include compressor or blower assembly noises, failure of air conditioners to start or to keep running, inadequate cool air flow or air quantity, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply, or even loss of air flow entirely.

Also discussed are various electrical wiring, fusing, overcurrent, and thermostat or control defects on air conditioners.

Air Conditioning Systems & Equipment FAQs-3

These questions & answers about diagnosing trouble with air conditioners and head pumps were originally posted at AIR CONDITIONING & HEAT PUMP SYSTEMS

A good place to look for diagnostic procedures is DIAGNOSTIC GUIDE A/C or HEAT PUMP.

Also see this series of A/C & Heat Pump Diagnostic FAQs sorted by major topic area are given at AIR CONDITIONING & HEAT PUMP SYSTEM FAQs

On 2017-08-16 (mod) said: do not try to re-use evacuated refrigerant

No not normally as there is a risk that it may be contaminated. The refrigerant would need to be cleaned of debris, burned oil, partriculates.

On 2017-08-16 by Anonymous

Can R410a be reused when it has been evacuated from a heat pump

On 2017-08-12 15:57:34.962266 by (mod) -

Koos

Please help us out here: just post questions on one page, as posting twice doubles the number of pages we need to visit just to try to give prompt answers to readers' questions.

Thanks.

See your question at https://inspectapedia.com/aircond/Air_Conditioner_Repairs.php#FAQ

On 2017-08-12 11:33:35.169175 by Koos

Air conditioner trips circuit breaker when set to hestart room. When set to cooling function it is working fine. Whst could be the problem

On 2017-07-12 12:22:55.200187 by Anonymous

Sounds s if a bad control board or relay lost turning on the heater or A.C..

Start at

https://inspectapedia.com/aircond/Air_Conditioner_Wont_Start.php

On 2017-06-28 18:47:57.526653 by Richard

I have a Senville Aura Mini Split system. It has two air handlers. One air handler works fine in both heat and cool modes. The other air handler blows air, but does not cool or heat. No service company will work on it if they didn't install it. I installed it myself and it used to work fine.

On 2017-05-19 02:31:08.653640 by (mod) -

Judy

I'd start by following the ductwork to see what has happened: something may be disconnected or a damper shut off.

On 2017-05-18 01:54:14.669878 by Judy

paid, 9000 for anew unit a Goodman .and placement of new ducts under house. Since install no air pulling from the return upstairs unit. down stairs is cool and upstairs hot
My previous unit gave equal temperature upstairs and downstairs. I was told I need to move my thermostat upstairs. . I have a 23oo sq ft house Thermostat has been there for the last 31 years

On 2017-04-17 18:05:59.791102 by Anonymous

ok everything is checked and set proper, air flows good, has correct freon level, heat pump heats but wont cool,

On 2017-04-12 02:22:40.180081 by (mod) -

Len,

I really can't say. Temperature and "inadequate" and what temperature was being measured where are all unclear. Is he talking temperature, angles of ductwork, what? If the inspector was paid for the inspection she ought to either refund the fee or answer clarifying questions about the report.

On 2017-04-11 16:00:36.137113 by Len

An inspector wrote that the supply air is only 92 degrees and is inadequate for the heat pump system. What does he mean?

On 2017-04-06 15:40:51.748049 by (mod) -

Check the steps in the order given in the article above - that's your best bet, Jeet

On 2017-04-06 15:11:22.745664 by Jeet

My Lennox rooftop unit is not heating or cooling. What should I check?

On 2017-04-01 01:32:00.215309 by (mod) -

I'm not sure. Hu.ming can mean a no th or is unable to start

On 2017-03-30 19:59:46.447662 by D.Huls

I have 2 desperate units , one for top one for bottom, when the one unit is not running Its quit , but the other makes a humming sound the whole time until it turns on , in which I can't hear because it's running then, please what could it be a should I be alarmed?

On 2017-03-11 09:27:40.985594 by Anonymous

Shining

Use the search box just above to find LOST COOLING CAPACITY to seeduagnosis and repair steps.

On 2017-03-11 02:17:46.271126 by Shibu

Heat is working but cool is not working why

On 2016-11-27 23:35:10.958382 by Mark

my york fan cool heat pump is not heating.
ZThe fan in on on the outside .
The wall thermostat is working but no heat.

On 2016-11-24 20:34:07.432794 by (mod) -

First of all, Randy, there may be no fresh air intake vent on your system. If a fresh air intake system was designed into your air conditioning and heating heat pump system there would be an outdoor fresh air intake connected to duct work that would ultimately intern connect to the return duct system in your home. there's no reason that a fresh air intake would be next to a thermostat.

On 2016-11-24 03:57:46.867779 by Randy

we have a 1968 Cambridge manufactured home, and installed a heat pump, but am unable to find the fresh air intake vent. I was told it should be by the thermostat, but found none. Any suggestions where I should look next? Thanks for the help

On 2016-11-23 02:50:20.745294 by (mod) -

Michelle,

I don't know what lines you are referring to, Nor how lines would double your electrical bill. However if you feel that incorrect work has been done at your property and that it has also been costly, that's a good question to take to your attorney

On 2016-11-23 02:46:59.120129 by (mod) -

Really Posting

AUTHOR:Michelle schulze (no email)
COMMENT:When my account and heat pump where upgraded the lines were not causing my utility bill to be 50% higher than it should be. Do I have a case for a lawsuit

On 2016-10-31 14:51:06.780487 by Alex

I have a rheem heat pump that keeps pumping down in cooling mode. And goes out on high head in the heat mode?

On 2016-10-23 18:32:29.122719 by (mod) -

Paul, Anon: that sounds like the power switch to your furnace.

On 2016-10-22 23:58:24.214002 by Anonymous

paul again it says to apply power by closing disconnect switch but i dont know what or where it is

On 2016-10-22 23:26:44.581545 by paul

hi how do i locate system disconnect switch on my lennox g26 series furnace it says to energize compressor heater to evaporate any refridgerant in crankcase please advise

On 2016-09-13 22:20:39.933997 by (mod) -

Doug the problem is likely to be a control, a start capacitor, or the compressor motor itself, not the main breaker powering the unit. Search InspectApedia for AIR CONDITIONER WON'T RUN to read some diagnostic suggestions.

On 2016-09-13 21:35:42.652455 by Doug Trombley

My daughter has a mobile home that is 30 yrs old. The heat pump is used for both air conditioning and heating. When the breaker is turned on, the air conditioning unit will run until it has reached the tempature set on the new thermostat. It will then turn off. It will not restart when temp rises and outdoor section runs but no air is flowing through ducts

. What is causing this from not restarting and cooling properly?

On 2016-09-02 21:13:15.228431 by (mod) -

Sounds stunningly expensive.
I'd ask whether or not a filter drier or two of them was or were intalled on the refrigerant lines - debris can indeed clog up a TXV.

A water bubble test? Perhaps soap test. Finding a small leak can be difficult, and worse, the leak may not be in the line that was rerplaced. Costly shotgunning, though I'm not comfortable second-guessing the on-site people who can see and know far more than I.

On 2016-09-02 21:04:17.668005 by ann

I have a 3 yr old Amana central AC.The TXV valve was replaced under warranty because no cool air was venting. This year the same thing happened and now they want to replace the line set...does this make sense? They say they can find no leak doing a pressure test and water bubble test. The new pipe set would be 4K on top of the new ac system installed 3 yrs ago.

On 2016-08-21 20:01:09.668192 by (mod) -

I don't have much upon which to base a guess, Marty, and can't tell if your system runs but doesn't cool, or doesn't even run.

If you search InspectApedia for LOST COOLING CAPACITY you'll see a sequence of diagnostic steps that should be helpful.

Your installer warrants their work, right? DId you call and ask for a visit and repair from the service tech?

On 2016-08-21 13:52:55.647494 by Marty

I had to have a condenser moved, and when it was reconnected it is not cooling. Systems uses 410A and new suction line was installed old liquid line was used and system was evacuated to 300microns

On 2016-08-04 21:28:34.347477 by (mod) -

Woody:

Check for cooling coil icing or a dirty cooling coil or duct leaks.

On 2016-08-04 01:30:04.589955 by (mod) -

Check for backup heat running when it should not.

On 2016-08-03 21:35:55.960493 by Ellis

I have a split unit with the thermostat on cool and set at 74 degrees the house not cooling down.when I switch the thermostat to the off position heat still comes out the vents. Could it be a bad thermostat or heat pump?

On 2016-08-03 15:04:56.648267 by Woody

My central unit seems to be working fine. The lines are very cold outside and inside. The air coming from the vents are strong but it's not cold. This seems to be the only problem. Everything else seems to be good.

On 2016-07-31 22:10:40.839896 by (mod) -

Karen

I'd call the installing company, speak with the service manager or owner, and politely, ask that they send an experienced, senior service technician to the home to determine what's wrong. Certainly one would expect an installing company to warrant their work including its performance to normal standards.

But we have no idea what's wrong: high heat gain, air leaks, duct defects, improper duct layout or design, improper sizing of the AC unit, improper refrigerant charge, a fan problem or what.

On 2016-07-31 21:31:25.669312 by Karen

We just spent $5200 for a new 5 ton Carrier AC for 1900 square foot house in Phoenix, AZ that was built in 1951. The first day the system cooled the house down with no problem. The second day the unit would not cool the house below 84 degrees which is unacceptable.

The licensed AC contractor has been out the past three days trying to get the system to cool the house down, and has even replaced various parts. Today they they checked the air coming out of the vent and it is 59 degrees, but it is still note the house down below 82 degrees and the motor runs continuously. The AC contractor has given up and said he doesn't why the new unit won't cool the house and why it never cycles off. His solution is for us just to watch it! the unit they replaced never had a problem cooling the house down and now I feel like for $5200 I should have an AC unit that will cool the house. What do you think is going on?

On 2016-06-29 18:36:03.279623 by (mod) -

Tish

The compressor is the motor that is compressing suction-side low-pressure refrigerant gas into a high pressure gas. The outlet from the compressor flows through a condensing coil - looks a bit like a car radiator with fins and tubing. A fan blows outdoor air across the coil to cool it.

That causes the high pressure high temperature gas to cool back to a liquid refrigerant state, and in the process of removing that heat from the refrigerant we're in effect moving heat from the building interior to outdoors.

Now if just the compressor motor has failed, that's a replaceable unit.

If just the condensing coil has failed - say by corrosion and leakage, that's a replaceable unit.

If just the fan or fan motor has failed, that's a replaceable unit.

The whole outdoor assembly is referred-to as the "Compressor/Condenser Unit".

The decision to replace the whole compressor/condenser unit versus replacing one or more of its parts would turn on several points:

- what's the age of the unit?
- is the exiting unit using a no-longer available refrigerant?
- what will be the total cost to repair individual failed components with the total installed-cost to replace the whole compessor/condenser unit?

On 2016-06-29 00:43:24.424023 by Tishtash

If either the compressor or condenser is bad, must they both be replaced?

On 2016-06-22 15:36:06.096586 by (mod) -

Search InspectApedia.com for LOST COOLING CAPACITY to read about possible causes and some things to check.

On 2016-06-22 15:25:32.576453 by karen williams fcch

ac unit will not maintain temp as the day gets hotter have temp set at 72 but it will go up to 86-90 but will start cooling off about 10pm.when u get up in the am its finally reaches the set temp

On 2016-06-22 15:12:16.126819 by Anonymous

ac unit loses temp as the day gets hotter. then cools off reach set temp late at night as temp goes down

On 2016-06-17 15:04:36.169618 by (mod) -

If the blower fan is not working running the A/C system won't work and is likely to cause cooling coil icing, blockage, leaks. I'd turn the system off.

On 2016-06-17 03:11:50.015105 by Diane

If the fan is not working, can I leave the unit on to get some air, or will that cause more problems? It's too late to call a tech tonight.

On 2016-06-10 14:23:12.752453 by (mod) -

David check your outside compressor/condenser: if it's not running the problem is probably there;

On 2016-06-10 14:21:42.923023 by Davjd Koci

warm air comes out of the vents?

On 2016-06-06 12:31:07.073561 by (mod) -

It's not clear to me why the need for a new heat pump would result in an intermittent problem, Paula.

Seems to me if the heat pump - presumably the compressor mortor - has failed, it would fail consistently. More likely there is a problem with a control, relay, wiring, voltage, etc. Call your HVAC service company manager, calmly discuss the problem with him/her, and ask for help from one of their senior, experienced techs. Keep us posted.

On 2016-06-06 01:54:06.484202 by Paula

A/c wiorks intermittently. Will work fine for a few days and then just start blowing uncooled air. When heat pump blows uncooled air it begins making metal on metal loud sounds. If I shut it off for a few hours and turn back on it works fine. Have had 4 visits from technician to determine problem.

Was told I needed new heat pump... So we put new one in. Same problem is still occurring. A/c running intermittently and heat pump making metal on metal sound when air is no longer being cooled. They have checked pressure, air handler , freon, circuits, etc. please help me. This has been going on for 3 weeks now. It is 95 degrees currently.

On 2016-06-05 23:43:51.038986 by (mod) -

Yes, Richard, a thermostatic expansion valve adjustment might be feeding refrigerant faster over to the low side on the lower HI & Higher LO pressure unit.

On 2016-06-05 23:16:07.459515 by Richard Ohran

The house I am working on has two identical units. The table of pressures on the unit shows high side of 300 and low side of 70 for the low humidity high 105 degree temperature that we currently have. One unit shows that and works well. The other has a high side of 270 and a low side of 90, but is working as well. My conclusion is that either the compressor is losing efficiency, or the expansion valve is worn. Could anything else cause this?

On 2016-06-01 10:26:26.082810 by (mod) -

It needs service, perhaps a refrigerant leak

On 2016-06-01 03:35:48.836851 by Karen

Why is it that my AC runs just fine during the day, but will not run at night? It's very hot outside, even at night. Every night I wake up soaked with sweat, and I have to run the floor fan on me, just to try and keep cool. This same thing happened when I lived in an apartment. I've tried to lower the temp, but then the thing will just keep running and running until I have to get up and turn it back up. And no, it's not hot flashes. My husband gets hot too...(:

On 2016-04-20 10:42:18.928090 by Anonymous

Renae the air conditioner or heat pump that is in cooling mode is removing moisture from air; that condensate is sent out of a condensate drain. It's normal.

On 2016-04-20 01:26:38.748313 by Renae

Water flows out when air conditioning heat pump is turned on

On 2016-04-16 12:17:59.935982 by (mod) -

NOt sure, Bary, try sending me some sharp photo using the page bottom CONTACT link. Perhaps there is condensate dripping on to the caravan roof, inviting mold or algal growth there.

On 2016-04-16 11:51:35.025683 by Bary

Why does my dometic air con roof mounted onmy caravan Send the roof black

On 2016-03-28 17:46:53.203059 by (mod) -

In the CONTINUE READING links see the live link for

Or see AIR HANDLER / BLOWER UNITS - home

where youi'll find procedures on troubleshooting the indoor air handler

On 2016-03-28 16:25:25.862589 by Anonymous

it works on the out side but it is not blowing in side house

On 2016-03-23 21:24:07.047427 by (mod) -

Kacey

The refrigerant needed is almost always included on the compressor/condenser (outdoor unit) data tag for a heat pump.

If your unit doesn't include that data,

Contact Luxaire at http://www.luxaire.com/ and armed with the model and serial number of your heat pump, ask for a free copy of the installation and users' manual. That'll specify the refrigerant needed.

On 2016-03-22 22:08:39.280621 by Kacey

Trying to find what kind of coolant is needed for a Luxaire Heat Pump model Bauh fo36ab.
Thank you :)

On 2016-03-17 23:32:15.665361 by (mod) -

Candy:

Check that the blower is really OFF. If it is and you feel a draft at the supply registers I suspect that there is an opening in the ductwork OR air is circulating by convection through the system, entering at an air return register. If the problem is serious, ask your HVAC company about an automatic duct damper.

On 2016-03-17 00:48:06.244656 by candy

Why when my air is off is there still cold air coming through the vents. In between cycles

On 2016-02-24 22:25:58.239968 by (mod) -

Jan,

First we need an accurate diagnosis of the problem. Some are not costly to repair. If you are facing a repair whose cost is a significant percentage of a new compressor/condenser (for example0 then it would make sense to go to a new unit.

But I certainly am not comfortable with the arm-waving "diagnosis" that you describe. Perhaps a polite call to the company's service manager and a request for a senior technician who an give a reliable diagnosis would be useful.

On 2016-02-24 15:56:19.226411 by Jan

My air condition is not cool enough and the technical said the air flow is not correct. He used the refrigerant gauge to check the pressure and the high and low pressure both are 120.The refrigerant type is R22. He said it may be the problem of the condense coil. I wonder is it true and the AC is more than 20 years. Should I replace a new one or fixed it?

On 2016-02-17 00:18:00.800836 by (mod) -

Sounds like a bad fan relay, control board, or fan start/run capacitor

On 2016-02-17 00:17:55.828202 by (mod) -

Sounds like a bad fan relay, control board, or fan start/run capacitor

On 2016-02-16 22:32:46.186422 by heavy

My heat pump unit work inside but my condenser fan want come on. I checked the voltage outside and it was right, so I push the contactor in by hand and the fan started up. I can hear a click when thermostat is turn on at outside unit but fan want come on.

On 2016-01-25 13:47:48.780351 by BC

My heat pump compressor is running but won't keep up indoor temp so aux heat is on. Compressor seems to be cycling to 'defrost' mode very often although there is no ice buildup. Temps have been within the range that system normally maintains indoor temp with out aux heating. Thoughts plese?

On 2016-01-24 19:25:59.701290 by (mod) -

Megan it's possible that the heater band intended to be used for defrost is not working on the compressor. But low refrigerant can also cause coil icing.

On 2016-01-24 19:01:27.971546 by Megan

My trane air conditioner won't go into defrost mode while its cold outside. The coils freeze up and once I spray it with water then the defrost mode kicks in.. Any idea what's wrong?

On 2015-10-20 13:31:35.506977 by Clint

I have a tempstar heat pump. When I turn heat on sometimes lithe blower works and sometimes it doesn't. When the blower does work it blows semi warm air never hot like it should be. And sometimes the blower stops and the pump keeps working just not blowing. What could this be?

On 2015-10-14 14:51:00.822651 by (mod) -

IF your system is a heat pump then it is designed to operate in cold weather to produce heat as well as cooling in warm weather.

In that case if you permit the system to run in cold or freezing weather, and if your heater thingy is not working, liquid refrigerant can enter the compressor piston when the motor runsd. The result is a ruined compressor and a very expensive repair.

Yes your heater thingy needs to work.

On 2015-10-14 14:18:43.821982 by Judy

My heater thingy to heat the oil in the compressor died. Is it necessary to replace it as I have one guy who says yes and another one says no. I have a Trane heat pump

On 2015-09-29 07:14:46.845400 by johny1234

My ac is not giving cool air. I had checked the condenser fan but its running, compressor is also running.
When i checked the thin diameter pipe it felt cool and touched the larger diam one it felt room temp like hot.
Suggest any opinions.

On 2015-09-25 17:23:58.613030 by (mod) -

George,

I suspect that either the outdoor temperature is below the cut-in temperature for your heat pump or there is a bad control board, relay, or temperature sensor.

On 2015-09-25 17:16:19.990602 by George

my heat pump runs when calling for cooling, but when calling for heat it won't run ,the Aux comes on

On 2015-08-24 23:25:47.526919 by (mod) -

There is probably a fan relay switch as well as a control circuit board as well as a fan start/run capacitor, any of which could be bad; your service tech will probably start by checking for presence of voltage at the fan motor and if absent, check for a loose wire.

On 2015-08-24 13:16:13.559189 by Debbie Posey

My fan on my Trane heat pump stopped working. Is there a relay switch anywhere on the pump itself?

On 2015-08-18 18:26:40.249673 by (mod) -

The compressor discharge line may indeed be hot; the job of the condensing coil is to cool and condense that hot, high pressure refrigerant from a gas back to a liquid.

On 2015-07-29 11:23:17.470399 by Anonymous

my aircon run but i notice the cooling coils wont cool and the discharge line is hot touch. The suction pressure is 56 psi in operating.What is problem of my aircon.chris

On 2015-07-22 17:09:18.067243 by (mod) -

The condensor fan runs or not under control of the compressor/condenser control board and switches. If the compressor is not running the condenser fan will stop. If the compressor fan is running without the fan then indeed a repair is needed.

If your system outdoor and indoor units run and blows out of supply vents but is only warm then no coolant is entering the cooling coil. That's a charge or a refrigerant metering device problem (most likely). A service tech will check high and low side pressures and may need to adjust, clean or replace the thermostatic expansion valve if the charge is proper.

On 2015-07-21 17:45:13.222711 by danjoefriedman

The specs for my unit says unit charge is 7 pounds 3 ounces. The filter was slightly dirty but the coil was definitely clogged. Once it was vacuumed off (still needs some cleaning) the air flow out of the vents increased quite a bit but it is still not cool air and doesn't explain the condensor fan stopping. The cooling coil is definitely not icing over-it barely gets cool and no windows or doors open.

On 2015-07-21 17:17:19.434662 by (mod) -

A/C

Adding 2 lbs of refrigerant means your system was probably close to empty. That's a pretty big leak. A pound a year is a big refrigerant leak for a residential A/C or heat pump system.

Normally a refrigeration system loses ZERO refrigerant. The charge is permanent unless there is a leak.

A dirty evaporator (cooling) coil will also reduce the cooling out put of a system because it blocks air flow. You may find the cooling coil also ices over because of the reduced air flow across it.

To distinguish between low refrigerant and a dirty coil (or dirty air filter or other duct defect) for the homeowner is relatively simple. If the air flow at your supply registers is weak I suspect one of the latter issues. If the air flow is strong but the air is not cool I suspect low refrigerant or a TEV that's not metering refrigerant properly.

At https://inspectapedia.com/aircond/Air_Conditioner_Temperature_Measurement.php we describe how to measure A/C temperatures for diagnostic purposes.

At https://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php we give typical A/C system temperatures you should find.

If your A/C system can't get the indoor temp below 80, unless you've got windows and doors open or some unusual heat gain situation, your A/C system is not working.

On 2015-07-21 16:27:38.141245 by (mod) -

Now AC, continuing the diagnostic suggestion:

You say your system runs but is not producing cool air - "With the thermostat set to 73 degrees, it's running closer to 80 (I had to buy a window unit to survive our 100 degree days)."

If you mean that air delivered from the supply registers is at 80F then the system is not cooling. If the compressor is working and the refrigerant charge is correct you should feel cool or cold suction lines at the compressor and you should be able to measure a temperature drop across the evaporator (cooling) coil at the air handler. If the cooling coil is not getting cold then most likely there is a problem with the charge or the refrigerant metering device.

See https://inspectapedia.com/aircond/Refrigerant_Leak_Repair.php#Refrigerant_Leak_Seal

for a discussion of using leak sealants

On 2015-07-21 15:51:14.628635 by A/C issues-blowing warm air

Last summer, the system wasn't cooling. The repairman added 2 lbs of refrigerant and everything was okay. This summer, again, the system wasn't cooling. The same repairman came out, added a pound of refrigerant and said I should put in the AC Leak freeze because it shouldn't have lost a pound.

I added it but was still having issues. Called repairman back out. that was when he said it could be the TXV, but he found the a-coil extremely dirty and cleaned it as well as he could without cutting it out and bathing it.

When I say "With the thermostat set to 73 degrees, it's running closer to 80..." I mean with the thermostat set to 73, it registers 80 degrees for the indoor temperature. Sorry for the confusion. The coil as well as the outside line is barely getting cool to the touch.

The system is barely cooling and the outside (condensor) fan runs for about 15 minutes then shuts off. It used to run as long as the inside blower was running. I'm not sure what else to try but I'm getting tired of paying the service guy $100+ every week with no change. The entire system is only 4 years old.

On 2015-07-21 by Anonymous

Last summer, the system wasn't cooling. The repairman added 2 lbs of refrigerant and everything was okay. This summer, again, the system wasn't cooling. Serviceman came out, added a pound of refrigerant and said I should put in the AC Leak freeze because it shouldn't have lost a pound. I added it but am still having issues.

When I say "With the thermostat set to 73 degrees, it's running closer to 80..." I mean the thermostat registers 80 degrees. Sorry for the confusion. The coil is getting mildly cool as well as the outside line.

The system is barely cooling and the outside (condensor) fan runs for about 15 minutes then shuts off. It used to run as long as the inside blower was running. I'm not sure what else to try but I'm getting tired of paying the service guy $100+ every week with no change.

On 2015-07-21 by (mod) -

A/C

I'm not familiar with using a "stop leak" product inside refrigeration systems and am nervous about the prospect of the "stop leak" product clogging up the thermostatic expansion valve (TXV). Of course if it does clog up the valve then that's nice for the service company.

On 2015-07-20 by A/C issues-blowing warm air

My A/C unit is blowing warm air. The repairman added a pound of freon and recommended I add a stop leak additive to the system. I added it but the air still wasn't as cool as it should be. He came back out, said I had "low head pressure" and may need new TXV if adding more freon didn't help.

It didn't, so I called him out to replace the txv and he found the A-coil was extremely dirty. He cleaned it as well as he could with my vacuum and said He could cut it out, acid bathe it and reinstall for around $550 or I could try cleaning it myself with coil cleaner

. I opted to try it myself. After he left, I noticed the condensor fan outside only runs for about 15 minutes then shuts off. I have to turn off the system and let it set for 30 minutes or so before trying again but it still shuts down. With the thermostat set to 73 degrees, it's running closer to 80 (I had to buy a window unit to survive our 100 degree days). Any ideas?

On 2015-07-15 by (mod)

Glen

The temperature difference you cite, if measured across the coil or close to that would be fine.

Refrigerant is not a consumable item. If there is a leak the best procedure is to find and fix the leak rather than to keep adding refrigerant.

- Editor

On 2015-07-15 by glen

My A/C unit was tested and there was 17 degrees difference in the temp from the cooling coils and the closest register is this good of should their be Freon added?

On 2015-07-15 by Luke Ducote

I've been having problems with a Freon leak for a couple of years now on an R22 system. A charge usually lasts several months, however the last charge only went a month before I was having problems again. Upon placing my gauges on the unit, I noticed the pressures were normal (75/210).

Although the condenser coils did not appear real dirty I cleaned them anyway. Both pressures dropped considerably so I added Freon. Then unit began running better/colder but is still having problems keeping up. I added a little more Freon (up to 85 psi) on the low side, however the high side is not getting any higher.

Did I put too much Freon? Could there be air in the system? I'm wondering if the compressor has been damaged but would rather not replace it as a means of troubleshooting. Any suggestions?

On 2015-07-08 by Johnnetta Hamlett

Hi I woke up one morning to the AC blowing warm air. One time before it was the capacitor so we changed the capacitor that didn't work so we changed the contactor.

This still did not work. However we can manually engage the contactor and the system will cool. Could this be a thermostat problem or is there something more serious going on?

On 2015-07-06 by (mod) -

sure - if you have time to read some of that material you'll be in better shape to understand (and trust) the HVAC technician.

Keep us posted

On 2015-07-06 by Melissa

Thank you..at least I have some direction to go..I will give my husband this info!

On 2015-07-06 by (mod) - AC never reaches desired temperature

Melissa you need an on site service technician. Possible causes are a refrigerant leak, ice-blocked coil, crimped or damaged ductwork or other causes.

At ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

you'll find an article titled LOST COOLING CAPACITY

that can help you diagnose the problem.

On 2015-07-06 by Melissa

Air conditioning turns on,blows cool air, but never reaches desired temp...what could be going on? We havent turned on the heat in 7 yes.

.usually run the air conditioning for about a week in the summer...we turned it on bout a week ago..worked fine.

Shut off during the day..ran it at night to sleep..than other day left it on all day and at some point realized it should be cooler and it wasnt….check settings, breakers...nothing wrong..what to do???

On 2015-07-01 by (mod) -

Thanks Liz, for the comment.

The proper repair is to clear the blocked condensate drain. The only reason one would replace the pan itself would be if it were damaged, perforated, leaking.

On 2015-07-01 by InternetLizard

+NCK Bethesda Md Can you try to find the drainage line and either clean or replace it? Sometimes there's also a pump that should be checked.

On 2015-07-01 by NCK Bethesda Md

My Carrier heat pump A/C has stopped functioning. The repairman says that there is a condensate collection pan as a part of the indoor unit in the attic of the house and that a drainage line is plugged, and the rising water level in the pan actuates a switch shutting off the fan/compressor unit situated outside the house at grade level. He says that the pan unit needs to be replaced at cost of about $400. Is this diagnosis credible? Any alternate diagnosis and remedies?

On 2015-06-16 by (mod) -

Then it's shot and should be replaced.

On 2015-06-16 by Larry

Noticed my run capacitor is leaking oil?

On 2015-06-16 by (mod) -

Larry if replacing the start/run caps didn't fix the trouble I suspect either a failing control board / relay or a compressor motor that is failing beyond the ability of the starting cap to kick it off. Perhaps your tech will check the current draw of the various motors involved to see if that's going on.

On 2015-06-16 by Larry

Trane Xl1600 heat pump cools down to set thermostat setting and then will not turn compressor back on and blow hot air in the home. This seams to happen when Phoenix temperatures reach 100 degrees. Replaced both start and run capacitors a couple months ago as issue started last summer was working fine until 100 degrees. Any assistance with this would be greatly appreciated.

...

Continue reading  at DIAGNOSTIC GUIDE A/C or HEAT PUMP or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

HVAC repair guides

• AIR CONDITIONING & HEAT PUMP SYSTEMS
• DIAGNOSTIC GUIDE A/C or HEAT PUMP
• DIAGNOSTIC DETAILS A/C or HEAT PUMP
• EDUCATION COURSES A/C / HEAT PUMP
• HOW AIR CONDITIONERS & HEAT PUMPS WORK
• PARTS - AIR CONDITIONING or HEAT PUMP
• AIR CONDITIONING & HEAT PUMP SYSTEMS

Suggested citation for this web page

REPAIR & DIAGNOSTIC FAQs for A/C-#3 at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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INDEX to RELATED ARTICLES: ARTICLE INDEX to AIR CONDITIONING & HEAT PUMPS

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