LG Split System Trips Out
I have a LG model LST243H-2, Heating and Cooling split system air con about 7 years old. It tripped out the circuit breaker 4 days ago! I have tested the 2 capacitors and they come up to specification.(1 motor start cap 90um and 1 dual cap, Hermatic 50 um and condensor fan 6um).I have also replaced the condenser fan motor with a new genuine part.($72.00 AUD) I also inspected and tested the internal electronic circuit board and it seemed fine! I can run the inside fan of the split system all day no worries, but when i switch to air con mode the outside unit is silent,no compressor noise at all, and after 1-2 mins the condenser fan spins for 1- 2 seconds and then trips out the circuit breaker. In this time the condenser coil does not even get warm.I just dont know how to test the compressor and any associated electrical components for this type of unit. I am missing some basic troubleshooting knowledge ! Any replies would be much appreciated.
Start by replacing the potential relay. This is a likely failure. Its a relay that takes out the compressor during the start cycle, and resets when off. Its likely you had a bleed resister across the start capacitor which unless you temporarily removed it would be unable to test. Some companys don’t use one because they run a live wire in the windings for a crankcase heater….anyway… The relay is an electrical switch and prone to failure…and a cheap fix.
A test on the compressor with the ohm meter. First label the three wires on the compressor pecker head. Remove the wires from the compressor. Set the ohm meter to its lowest setting. Measure and write down the values of C to R, C to S and S to R. C to R should be the lowest, C to S should be 3 to 5 times what was read on C to R, and S to R should be the highest and be = to R+S(+/-) .5 ohms. All three terminals to ground should be open (as if touching nothing).
