Air Conditioning & Heat Pump FAQs Set #4

Questions & answers about fixing problems with air conditioners & heat pumps posted by readers at the A/C or heat pump diagnostic home page.

Air Conditioning & Heat Pump Troubleshooting FAQs-4

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 given

at AIR CONDITIONING & HEAT PUMP SYSTEM FAQs

I could manually push in the single button to start the compressor and fan manually.

Last week, I woke up to the indoor temperature a few degrees high. Warm air was blowing in. I went to my outside unit and the fan was not running. I replaced the capacitor and it worked.

But the air conditioning couldn't keep up at night. During the day when it was around 99 my home was nice around 76 but at night around 81.

Yesterday the compressor was not running. It was getting power. Today, I put in a hard start kit and it worked. But about five hours later the compressor was not running, just the outdoor unit fan. I pulled the power and when I powered up again, even the fan and compressor did not start.

Multimeter showed me around 25V on the two lines coming from indoors on two sides of my contactor (and 120 V on the other two connections). One of the 25V lines connected to the two sensors on the refrigerant lines. But the contactor didn't engage.

I could manually push in the single button to start the compressor and fan manually. What would cause three different issues within one week? I plan to replace the contactor tomorrow. Another night of muggy 90+. - On 2011-07-09 by Jeremy -

Condenser fan runs at half speed

Jeremy:

What does the contactor look like, and where is the push button you're referring to?

I'm wondering if my outside compressor/condenser unit has similar problem where the fan runs at half speed even when the indoor thermostat is switched OFF. - On 2011-07-09 by TN-Goose -

Reply by (mod) -

I agree that a bad contactor relay could also prevent a compressor from running, but I suspect that burning A/C controls, switches, contactors, or circuit breakers will often be traced to a compressor that is seizing and drawing high amps.

 

Replacing compressor capacitor didn't fix the trouble

I replaced the 50/3 MFD capacitor with a new one. Noticed the outside compressor fan running at half-speed as before when the indoor TT is set to OFF (yes, it's baffling).

As soon as the indoor TT was switched to ON, the fan spun to full speed, then the 30Amp breaker tripped immediately (maybe due to compressor malfunction).

Was hoping the new capacitor would resolve the issue, but looks like seized compressor and/or a bad controls in the outdoor compressor/condenser unit as you mentioned. Thanks again for your help. - On 2011-07-09 by TN-Goose -

Moderator reply:

Before launching into a compressor replacement, I'd want help from an on-site HVAC repair technician who can check the current compressor's operation, current draw, and staring trouble.

Particularly I'd also want to check the control relay and board.

 

Can a lack of cooling agent stop the compressor from running?

I have an A/C system that is no longer cooling. The serviceman came out and said we needed a new compressor. he stopped by to drain Creon/r22 or what ever cooling agent but said there was none in the system. Can a lack of cooling agent stop the compressor from running? - On 2011-07-08 by Ken -

Reply by (mod) - Yes, A lack of coolant will not stop a compressor motor from running right away but pretty soon it will ruin the motor - lack of lubricant

A lack of coolant will not stop a compressor motor from running, the motor will run but if there is too little or no refrigerant gas (in your case Freon R22 which is obsolete) the system just won't cool the air blown across the evaporator coil.

But because refrigerant also includes a lubricant needed by the compressor, if your system loses all of its refrigerant and the compressor motor keeps running, yes it may be ruined by lack of proper lubrication.

You need a new compressor if the old one is seized or if it is so worn that it won't compress the refrigerant gas. If your system is not cooling because it's lost refrigerant, it may be possible to re-charge it. Ask for specifics of how the tech knew the problem is the compressor.

 

Can a refrigerant overcharge Ruin a Compressor?

A service tech left my air conditioner with a huge overcharge according to the next guy who came to my house to fix it. The second guy says the first guy killed my compressor motor.

Can a refrigerant overcharge ruin an air conditioning compressor? - Michael

Reply by (mod) -

Michael:

Can a refrigerant overcharge ruin an air conditioning compressor? Sure. Liquid slugging - liquid refrigerant from an overcharge can enter the compressor motor.

I'm not expert enough to make a general comment about ALL A/C compressors, but certainly there are some designs in which an overcharge that sends liquid refrigerant into the compressor piston or valve area can ruin it promptly. Imagine a piston trying to move in a cylinder that has liquid in it where just compressible gas is supposed to be found.

 

HVAC tech discusses repairing a Coolair Split Unit - one compressor unit is not cooling

im working on a coolair spilt unit with 2 evaporator's 1condenser and 2 compressor's all fan belt's and condenser belt are good .

all filter's were changed ,one of the evap section is discharging 55deg air at 86deg outside temp and gauge pressures of 65/245 and the other evap at 86deg out side temp is discharging 64deg with pressures of 78/265 can you help . 2011-07-07 by tony -

Reply by (mod) -

Tony: Those pressures for the two units are both practically in the same range. Did you check the TEV (Thermal expansion valve) ?

 

The outside unit cycles on and off though the inside fan will not.

my fan is set on auto, and the inside fan will not cycle off. the outside unit cycles on and off thouth the inside fan will not. It use to. It is like someone set the thermostat fan to the on position. Even in the auto position the fan never turns off. The house is cool and everything else is fine. What would cause this? - On 2011-07-06 by Colleen -

Reply by (mod) - if your indoor air handler fan won't turn off,

Colleen: if your indoor air handler fan won't turn off, either the thermostat is never being satisfied or someone has set a switch to run the fan continuously (or thermostat control wires shorting together are causing it to run)

In addition to the "fan on" switch on some thermostats, the fan limit switch found in the air handler of many systems includes a white button that can be set to make the fan run full time. Search InspectApedia for "fan limit switch" to find the article describing that device.

Follow-up by Colleen

Thank you, I will read the InspetApedia on "fan limit switch". We thought it might be the thermostat and replaced it twice. Replacing this did not change the fan staying on problem.

 

Why is return air being taken from my garage? Garage is too hot.

Why am i getting return air for my hvac from garage ceiling .air is so hot in garage area - On 2011-07-03 by al entez -

Reply by (mod) - block off un-wanted return air but check the totasl

Al, if your garage is not being cooled AND if there is adequate return air supply from the rest of your building, you can simply block off that garage return-air inlet. That's what I'd do.

But be sure that you've got enough return air elsewhere in the system.

See RETURN AIR, HVAC

 

After cooling for a while A/C stops working and air temps rise

My air conditioner works great for awhile and then the cold air stops coming out and the air temp starts to rise. The outside fan is still running. Can anyone help? - On 2011-06-27 by sherry -

Reply by (mod) - check for iced coil

Check for a cooling (evaporator) coil in your indoor air handler: is it blocked by frost or ice? If so that's the trouble.

See detals at FROST BUILD-UP on AIR CONDITIONER COILS

 

Air Conditioner / Heat Pump Current Draw Issues

If the compressor is rated for 14Amp and is running at 11.8 Amp dose this mean the compressor is ready to burn out?

If the compressor is rated for 14Amp and is running at 11.8 Amp dose this mean the compressor is ready to burn out? - On 2011-06-17 by jim

Reply by (mod) - no

Jim:

About your question "If the compressor is rated for 14Amp and is running at 11.8 Amp dose this mean the compressor is ready to burn out?"

Not in my book. Usually when a compressor is seizing up it will draw abnormally high amps not lower amps. Take a look at the RLA figure for your unit.

Follow-up comment by jman

To jim no that the rating for design conditions was the temp outside 95 if not then it is good

Followup by jim Hanlon

Jman the outside temp was over 95

 

Compressor runs but no air is coming out of supply registers

outside compressor and fan seem to be working fine, but no air blowing out of the inside ducts? please help! thank you - On 2011-06-16 by Mike

Reply by (mod) - If no air is coming out of your supply registers

Mike:
If no air is coming out of your supply registers, the air handler is not working; be sure that there is power to the unit and the thermostat is properly set to COOL; if your thermostat has a FAN ON switch you can try to just force the fan on to see if the blower will work at all.

See AIR FLOW TOO WEAK

 

Refrigerant lines not cold, compressor makes GRR noises and is not running

There is no ice on any lines -- there not even cold. I went out there and turned it on again. But this time i lissened. I heard the compressor make a grr sound then a min or 2 later a grr sound again then never made noise after that. Anyone have any idea. My recent post is 6 days prior to this one. - On 2011-06-15 by Andrew -

Comment by TN-Goose

To Andrew: while troubleshooting my compresson/condenser unit problem, I came across a tip that said that some special capacitor, called hard start capacitor, can be added to give a boost start to the compressor (especially older ones that are hard to start). It said the hard start capacitors are a combination of a capacitor and a built-in relay. Supposedly, they are inexpensive.

 

Air conditionerdoes not turn on

I turn my thermostat to cool set the temp fan kick in but nothing turn on the air conditioner. I don't hear the fan kick in on the unit. We has a string of hot days. The ac would turn off but noticed when the night got cooler the ac was still blowing air but not cool and i didn;t hear the unit humming. I have someone comming tommorow just worried its going to be expensive meaning no air for me this summer. - On 2011-06-15 by kitt

Reply by (mod)

Kitt, see the steps given at AIR CONDITIONER WON'T START

 

Air Conditioner Condenser/Compressor Unit Stops running and Inside Air Handler Blows Warm Air - Reset Button gets it going

During the day, my condenser stops running while the air blows warm inside. When I go out to check it what's going on, I have to press the reset button to get it going again. It doesn't run long before doing the same thing so I've been leaving it off mostly because it can't keep up with the 90+ Texas temps during the day.

The crazy thing... at night it works just fine (a cool 74). So between about 7pm and 10am I have AC but the rest of the day... it's hot. This has been going on for two weeks. Any ideas? - On 2011-06-13 by RonniE K

Reply by (mod) - press the reset button to get it going again

Re: "I have to press the reset button to get it going again. It doesn't run long before doing the same thing"

If a motor keeps going off on thermal overload reset chances are that the motor itself is failing and needs replacement.

Something else could be causing the motor to overheat however, such as inadequate air flow when the compressor unit is blocked by shrubs or is located too close to a building.

 

Where do I get a Hard Start Capacitor for my Air Conditioner Compressor Motor?

A/C Compressor resistance readings at Terminals Red+Black=32.3 ohms, Red+Purple=2.8 ohms, Purple+Black=34.6 ohms.

I removed the capacitor from the outside compressor/condenser unit. It's a dual 50/3 MFD 50/60Hz type, but no indication as to the +/-% MFD. The HERM side measured 44.5uF and the Fan measured 3.05uF. Since the HERM terminal measured below 10% of specified 50 MFD, the capacitor is no good.

Do you agree? Do you know of a good source for purchasing this type of capacitor?

I also checked the resistance of the compressor....

terminals Red+Black=32.3 ohms, Red+Purple=2.8 ohms, Purple+Black=34.6 ohms.

The same 3 color terminals measured individually to the body of the compressor measured as overload (O.L on my FieldPiece multimeter). Do these resistance reading indicate a bad compressor? -

I removed the capacitor from the outside compressor/condenser unit. It's a dual 50/3 MFD 50/60Hz type, but no indication as to the +/-% MFD. The HERM side measured 44.5uF and the Fan measured 3.05uF. Does this mean the capacitor is bad?

I also checked the resistance of the compressor....terminals Red+Black=32.3 ohms, Red+Purple=2.8 ohms, Purple+Black=34.6 ohms.

The same 3 color terminals measured individually to the body of the compressor measured as overload (O.L on my FieldPiece multimeter). Do these resistance reading indicate a bad compressor? - On 2011-06-17 by TN-Goose

Would a dual capacitor specified as 50/3 MFD and 50/60 Hz be different than one specified as 50/3 MFD and 60/50 Hz?

Would a dual capacitor specified as 50/3 MFD and 50/60 Hz be different than one specified as 50/3 MFD and 60/50 Hz? For example, is there any significance to the frequency spec being shown as 50/60 Hz vs. 60/50 Hz? - On 2011-06-14 by TN-Goose -

Reply by (mod) - Hard start capacitors and motor start/run capacitors

Hard start capacitors and motor start/run capacitors are discussed in detail beginning in the article found

at CAPACITORS for HARD STARTING MOTORS

 

Ice on the suction line at the condenser Unit

Ice on the return line at the condenser? - On 2011-06-11 by Herb M. -

Reply by (mod)

Sounds like you're missing refrigerant line insulation. See

REFRIGERANT PIPING INSULATION

 

Outside Condenser Unit Won't Stop Running

My ac fan outside will not stop running...Sounds like motor & fan ran all night...Can we run the air like this...What would cause this to happen and how can it be fixed? On 2011-06-07 by livvy -

Reply by (mod) - If your outside fan keeps running

Livvy:

If your outside fan keeps running it's possible that that's normal IF the compressor was working also during the night - under heavy continuous cooling loads the system might run a lot.

But if the compressor shuts down and the outdoor condenser fan keeps running for more than a few minutes I suspect that there is a bad switch or control board in the system.

 

On 2011-06-06 by Richard - Compressor has failed mechanically (drawing far too many amps).

Just a follow-up for future readers. Compressor has failed mechanically (drawing far too many amps).

My no-name (builder grade) outside unit trys to start but won't. The fan runs fine (I replaced it last year)but the compressor tries to start for about 2 seconds, then stops. About 45 seconds later it will try again. Same results. It never trips the breaker.

I had a tech come out while I was at work and he "thinks" the compressor is locked up. I checked the resistance today and got .001 C-R, .002 C-S, and .002 R-S. My DMM reads OL (overlimit) when checking all three terminals against the compressor case. I'm leaning toward low refrigerant (is there a low pressure shut-off on home systems like in cars?).

Tech that came out told the wife it wasn't low on refrigerant but...? I'm gonna swap a known-good Run-start cap from my other unit and try that. I guess the compressor could've failed mechanically. Any thoughts?

On 2011-06-07 by (mod) - a high amp draw on the compressor circuit

Thanks Richard for the followup A/C diagnostic detail. Indeed a high amp draw on the compressor circuit is one of the basic diagnostic tests that lead a tech to think the unit is seized or failing.

The high pressure (smaller diameter) refrigerant line is not normally cold in cooling mode but could be warm or even hot depending on where along its length you are checking on its temperature.

The low pressure or suction line (the larger diameter refrigerant line) is normally cold when the air conditioner has been running for a while and can even show frost on uninsulated sections.

I'm not sure from your description if I can say that the high pressure warm line is a problem, but if your low pressure line is never getting cold I suspect a lost refrigerant charge (or the compressor is not running at all).

 

On 2011-06-06 by Michael - air conditioning unit stopped working after being charged

My air conditioning unit stopped working after being charged 2 weeks ago (ran great afterwards).

After bringing out a different AC company, he said the last guy overcharged the system and the compressor was shot. He said he was certain of this because he found liquid refrigerant on the "gas side". Is this true? Is there no other way for liquid to be on the gas side of the system unless the system was overcharged? (Long story short, my landlord is trying to stick me with the bill because I called the first company to come out, which he had no used before)

 

On 2011-06-04 by TN_Goose Air Conditioner Compressor trips the breaker

The outside compressor/condenser unit of my central air conditioner, which is wired to a bi-pole 30amp circuit breaker, started to trip the breaker whenever the indoor thermostat turns ON the air conditioner. Never had this issue in the past 6 yrs.

Despite the breaker being tripped, there's air coming out of the supply registers, but it's warm obviously due to the compressor/condenser unit being tripped OFF.

What could be some reasons for tripping the breaker? One strange condition I noticed is that when the indoor thermostat is switched to OFF (not on Cool), the breaker stays ON without tripping, and the compressor/condenser unit's fan rotates at about medium speed, instead of being OFF. Any suggestions or help will be appreciated.

On 2011-06-05 by (mod) -

TN_Goose:
It sounds as if your outside compressor/condenser is not starting; a compressor that has seized or is drawing high amps would trip the breaker. I'm baffled about why the outside compressor fan would run at all when the indoor TT is set to OFF; could be a bad control board or circuit or one that was damaged during compressor burnup.

On 2011-06-05 by TN_Goose

Thank you for the quick reply. When you say "bad control board or circuit", are you referring to the ones in the compressor/condenser or TT?

Would a faulty capacitor (one that might be almost ready to fail) cause the compressor fan to run? It's really odd for the fan to run with TT set to OFF. I opened the outer casing of the compressor/condenser today and checked the apprearance of the capacitor (looks fine..

.no bulging or corrosion anywhere...couldn't check for the MFD..waiting on the just purchased HVAC/R multimeter shipment), and all wiring connections from the compressor and the fan look OK (no shorting or loose connection). What would cause the compressor to seize or burnup? I'm wondering if the extreme hail storm and heavy rain that partially flooded outside compressor/condenser area (about 3-inches of water) has anything to do with it.

On 2011-06-05 by (mod) -

Typically for the symptoms you described, if it's not a thermostat problem, the service tech will probably do some simple electrical tests of the compressor/condenser unit, check system pressures, and will visually examine the controls and circuits in the outdoor compressor/condenser unit for an obvious problem before doing more sophisticated tests.

FYI sometimes a capacitor can be bad without bulging.

Compressors can seize from internal wear, a problem that can be accelerated if there is moisture or if there are contaminants in the refrigerant.

On 2011-06-05 by TN_Goose

I'm going to check the capacitor MFD first, then if it's not the capacitor issue, I'm going to call Hiller Air Condtioning. I'll post the result of the root cause finding. Thanks again for your help.

On 2011-06-05 by Jeff - Janitrol unit fan makes buzzing sound and doesn't spin

My Goodman Janitrol 2 ton turns on but the fan just makes a "buzzing" sound instead of spinning.

Moderator reply: If your A/C is buzzing

Your fan motor may be shot or there can be a control board problem - the service tech might first try replacing the fan motor capacitor(s).

If your A/C fan is buzzing but not spinning my first guess would be that the motor is burned up or perhaps easier, the motor needs a starting or start/run capacitor. Under COMPRESSOR & CONDENSING COIL, A/C check out the article titled CAPACITORS for HARD STARTING MOTORS (see links(links found at the ARTICLE INDEX near the end of this page) ).

 

On 2011-06-04 by Pahugh

Have Goodman home unit with R22 about ten years old. Compressor replaced 5 years, one month ago (out of warranty). Evaporator core recently replaced due to leaks, and unit has not worked properly since providing minimal cooling.

With outside temperature of 95, have head pressure of 210 and suction pressure of 118. Suction line is sweating at the core and outside but little cooling. I am being told that the compressor is bad. Could something have happened during the evaparator core replacement to cause this, or could there be a problem with the new evaporator core.

As the homeowner I am suggesting evacuating and recharge but this may be a futile exercise. Other causes have been ruled out (i.e. airflow okay, no freezing up, etc.)

On 2011-06-05 by (mod) - pressure readings may indeed indicate that the compressor has lost an internal seal

Pahugh:

I'm not sure, but those pressure readings may indeed indicate that the compressor has lost an internal seal or has a bad internal valve. Before replacing the compressor you need to ask what refrigerant was used to recharge your system when it was last repaired. Putting a new A/C refrigerant into an older unit that was designed for a different refrigerant wont' work properly.

On 2011-06-02 by dh in texas A/C unit stops working in hottest part of the day

Here recently, my heat pump unit has started to act up. It tends to work well for the better part of the day.

The compressor will run and there is good cold air flow out of the supply registers. However, late in the afternoon (peak heat time) the heat pump fan will abruptly stop (with great deal of heat near heat pump fan). Restarting the system after a 30-45 minute "off" cycle will generally restore its operation. Any ideas?

Reply by (mod) - heat pump that works ok in cooling mode until late in the day when it shuts off

DH:
Your description of a heat pump that works ok in cooling mode until late in the day when it shuts off and is very hot makes me think that a motor, possibly the fan motor is overheating and shutting down on thermal reset. Some electric motors contain a built-in thermal overload switch that will reset itself automatically when the motor cools down.

If that's what is happening the motor could need replacement, or it may be that the compressor is in a very hot location and / or is not seeing adequate air flow. I see this problem when a compressor unit is installed too close to a building or when airflow in or out of the unit is blocked by a building wall or shrubbery.

It's worth a service call to have a trained tech look at the installation and motor. Let us know what you find - it will help other readers.

If the system is actually running but air flow becomes weak, that's a different problem: probably an ice or frost blocked cooling coil in the air handler.

 

On 2011-05-31 by Laura - New (replacement) AC is not working

I had my furnace replaced a couple of months ago. The A/C was in fine working condition last summer. When we turned on the A/C last week it wasn't working so we called the company that replaced the furnace to come out and make sure that it was all properly hooked up since the furnace was replaced

After inspecting it, they told us that the intake valve wasn't working and it needed to be replaced, at about $450. Does this sound a little fishy seeing that it was all working fine last summer? I feel like they are trying to take advantage of us. Any comments, suggested questions to ask or feedback would be GREATLY appreciated! Thanks!

On 2011-05-31 by (mod) -

Laura: I'm not sure what the "intake valve" is referring to. Certainly there are come controls such as the thermostatic expansion valve that meters refrigerant into the evaporator coil that are not so costly for the part, but because its replacement requires the time and labor to empty, vacuum, and then recharge the system, the total cost of the job can be several hundred dollars.

Ask the A/C repair company to be more clear on just what part failed and what's involved in its replacement. Let us know what you're told as it may permit further comment and/or it may help other readers.

On 2011-05-31 by Laura

Thanks, I'll update tomorrow after they visit.

 

On 2011-05-30 by matthew - compressor cycles on and of every few seconds or minutes.

Are compressor cycles on and of every few seconds or minutes. What can we do to fix this systems not even a year old

A/C compressor short cycling every 10 seconds!

I have the same problem as Matthew: my compressor cycles on and of every ~10 seconds. I is about 5yr old. What can we do to fix this system. Please help. Thanks! - On 2011-05-31 by Joe -

Reply by (mod) -

Some causes of a home air conditioner compressor short cycling on and off too rapidly include these:

1. loss of refrigerant - a refrigerant leak in the system. You may be able to repair the short cycling problem temporarily by recharging the system but the proper repair is to find and fix the leak.

2. coil icing: the evaporator coil (cooling coil) is iced over (such as due to improper refrigerant charge or dirt or a reduced air flow due to a dirty filter) - take a look in the air handler to see if the coil is blocked by ice or dirt.

3. oversized air conditioner: if the short cycling has always been a problem since the day the system was installed, there is a good chance that the unit is too big (too many BTUS) for the space being cooled.

A more subtle version of this same problem is that you've done something like closing doors or adding a partition that had the effect of reducing the size of the space being cooled. Sometimes we can mitigate this problem by running the blower fan at a lower speed or by opening interior doors to increase the size of the space being cooled or even by moving the thermostat.

 

Air conditioner unit had a refrigerant leak, was recharged, and now we have the trouble again 2 months later! Also air flow is weak and warm.

Our ac was serviced two months ago and the repairman said it had a leak.

$400 later it was recharged with coolant and now the A/C is doing the same thing.

Very little pressure coming out of vents and no cold air coming out. Does anyone know what I can do for the weekend? It is stifling! - On 2011-05-28 by Les

Reply by Mod: don't just keep adding refrigerant to a leaky air conditioner or heat pump

Les:

Watch out: A refrigerant leak that was "fixed" simply by adding refrigerant - a re-charge - is not as good a repair as a leak that was fixed by finding and fixing the leak - you'll just have to keep adding refrigerant. And your system will keep contaminating the environment.

In my opinion the right repair is to find and fix the refrigerant leak. That is especially true and urgent when the new refrigerant charge was lost in just a couple of months.

But weak air flow out of the vents would not be due to a refrigerant leak; more likely a clogged filter or crushed or disconnected ductwork, or a blower fan problem.

That's something you can check right away, yourself.

See these diagnostic procedures

AIR FLOW TOO WEAK

AIR CONDITIONER BLOWS WARM AIR

DIRTY AIR FILTER PROBLEMS

 

Compressor Condenser Unit Suction line gets warm to the touch

After my condenser is turned on for about 4 minutes the suction line starts to get warm to the touch. can you tell me what the problem may be - On 2011-05-27 by JMONTE -

Reply by (mod) -

JMONTE:
If the HVAC suction line gets warm, you may be out of refrigerant, or the system may be running in heating mode if it's a heat pump.

 

Thank you to our readers for their generous comments

THANKS FOR YOUR RESPONSE!
...THIS IS SO COOL!! Have to tell my friends about you! - On 2011-06-08 by Livvy

Cool website thanksss - On 2011-05-28 by jay

Thanks for so much info. been a big help. more power! - On 2011-06-17 by robert

Reply by (mod) -

Thanks for the Kudos and encouragement. We've worked hard on this material for over twenty years so we're very grateful when readers find it useful and trusted.

We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles.

 

...

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

Recommended articles

• AIR CONDITIONING & HEAT PUMP SYSTEMS - home
  • AIR HANDLER / BLOWER UNITS - home
  • BURNED-OUT COMPRESSOR
  • CAPACITORS for HARD STARTING MOTORS
  • CHATTERING RELAY CONTROL SWITCHES
  • COMPRESSOR / CONDENSER REPAIR - home
  • COMPRESSOR / CONDENSER INSTALLATION ERRORS
  • COMPRESSOR / CONDENSER LEVELING REQUIREMENTS
  • COMPRESSOR CONDENSER NOISES
  • COMPRESSOR MOTOR INSULATION
  • COMPRESSOR MOTOR REPLACEMENT
  • CONTACTOR RELAY DIAGNOSIS & REPAIR
  • CONTROL CIRCUIT BOARD, A/C
  • COPELAND ELECTRICAL HANDBOOK [PDF]
  • CRANKCASE HEATERS
  • ELECTRIC MOTOR DIAGNOSTIC GUIDE
  • HARD STARTING COMPRESSOR MOTORS
  • HEAT PUMP OUTDOOR UNIT DEFROST CYCLE
  • LONG-ON CYCLING AC COMPRESSOR
  • NOISES, COMPRESSOR CONDENSER
  • REFRIGERANT PRESSURE READINGS & CHARTS
  • SHORT CYCLING AC COMPRESSOR
  • TIGHT or SEIZED AC COMPRESSORS

Suggested citation for this web page

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

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