heat pump compressor not running
#1
03-16-02, 11:03 AM
heat pump compressor not running
It got warm enough today to crank up the AC unit. 4 ton Nordyne air to air heat pump, compressor replaced about 2 years ago.Overall unit is 12 years old. Found the 50 amp breaker tripped, went outside after resetting the breaker and turning the system back on, all I hear is a faint buzzing at the compressor, the thermal overload did not kick off, I tried to reset it. Left it that way and sure enough breaker tripped again, breaker won't reset with unit running (i.e. air handler running without compressor) Just seems that the compressor won't start. How do I test the starting capacitor? If it's good , does that pretty much assure me that the compressor is kaput again. This is the 3rd compressor in 12 years, not much to be said for these units.
#2
03-16-02, 11:25 AM
breaker trips on start
Just shut everything off, reset breaker and checked wiring for loose/bad conections all OK, when the unit cycled back on as soon as the air handler kicked on the breaker tripped immediately. As far as my limited knowledge goes, that means a dead short and probably the compressor is grounded?
#3
03-16-02, 04:16 PM
Since you've checked for loose wiring and burnt terminals, the compressor probably is bad. You need to have a good ohmeter to check out the caps and comp.. Remove the comp terminal cover and pull the wires off the terminals. Use your ohmeter to check for open, shorted or grounded windings. To test the capicators, pull the wires off and test for open or short.If ok, you can set your ohmeter on x10 or x100, short across the terminals with a screwdriver, then put your leads on both terminals. If the cap is good the needle will jump up high and slowly fall back to zero. This won't give you its rated capacitance but will let you know it probably is still good. Also check to see that the contactor isn't fused or burnt. If the above is ok, check out the fan motor. Can't comment one way or the other on Nordyne but if you've had three comp.changeouts in 12 years, someone ain't doing their job. I'd be for getting me an established RSES trained tech. However, after 12 years, you m,ight want to consider a newer OD unit
#4
03-26-02, 09:06 AM
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Last edited by jonathanisaac; 08-04-06 at 08:59 PM.
