air conditioning trouble.?

Jun 5

i have a carrier 25tonner split system A/C, when i turn it on and the compressor is energized, it's contactor would make a sound, like that of a hammer, and the spark inside the contactor is visible, and after a while, the CB would trip. i already check the control pad anfound no problem, i already checked the compressor, and everything is just normal, i already cleaned up the arcing residue in the contactor but still the same problem would happen.. what should i do? i am an aircon technician with a lot of experience, but i cant seem to troubleshoot this one, can someone please help me? thank you.

I'm guessing this to be a 240 v single phase system. If the contacts on the contactor aren't burnt, you may want to consider replacing the start assist (ptcr) if it has one. If not, you may wish to consider a hard start kit. Sounds like the compressor's having a hard time starting. Although it's rare on a 240 v compressor, you may want to take a mega ohm reading on the compressor, you should have a minimum of around 250m ohms to ground; if you have less than that the insulation in the compressor may be breaking down and offering a path to ground inside the compressor that won't show up with a typical ohm / continuity meter. Good luck

Air Conditioning - what's going on?

Filed under: Carrier Air Conditioning

4 Responses to “air conditioning trouble.?”

dvdacmn, on June 5th, 2009 at 12:03 pm Said:

if your experienced tech how many amps is it drawing when it fires without looking at it my guess is you have a restriction it starts drawing high amps & trips breaker unless it has one of those plug in connects to the comp might have a short go back to basis trouble shooting
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S L, on June 5th, 2009 at 12:14 pm Said:

chk 24v to contactor…make sure there is'nt a voltage drop..if not the contactor coil is bad get a new one
References :
uncledjm14, on June 5th, 2009 at 12:30 pm Said:

I'm guessing this to be a 240 v single phase system. If the contacts on the contactor aren't burnt, you may want to consider replacing the start assist (ptcr) if it has one. If not, you may wish to consider a hard start kit. Sounds like the compressor's having a hard time starting. Although it's rare on a 240 v compressor, you may want to take a mega ohm reading on the compressor, you should have a minimum of around 250m ohms to ground; if you have less than that the insulation in the compressor may be breaking down and offering a path to ground inside the compressor that won't show up with a typical ohm / continuity meter. Good luck
References :
magiccharm, on June 5th, 2009 at 12:48 pm Said:

replace the start or dual capacitor
References :

Air Conditioning 2.0