LG split tripping breaker

[Kirky]

Hi all been called to a LG split system it's a floor mount indoor unit and the outdoor has 2 compressors. When I arrived power was off so immediately gained access to distribution board and breaker was tripped. Immediately thought compressor was fault. Reset breaker and unit started and ran fine loaded up the system and ran it on full load both comps in everything seemed fine. Checked comp.amps all ok. Watched the unit cycle on and off for good hour no problem. Was just getting customer to sign service report and the system tripped breaker. Reset and it tripped again before I got to outdoor by now it was pitch dark so put in some temp cooling and left. If it was the comps causing the trip then why would it run for good hour and half I'm thinking it must be comp or contactor as if it was the capacitor or defective wires then it would of tripped sooner. Sorry don't have model numbers but can get if need be. What you think am I going in the right direction or missing something. The breaker is a 32 amp c type which should be ok for the unit.

[install monkey]

earth leakage, or if the neutral in the isolator is switched,that can cause problems, ensure the neutral is on the terminal block instead of the switched pole,also circuit breakers can get warm and weaker- inverters should be on a d type breaker(motor rated)

[r.bartlett]

......... inverters should be on a d type breaker(motor rated)

Why is that?

[AGSelec]

Hi. Have a look rated amps equals accual amps. A faulty cap can cause this problem. The insulation resistance is ok of compresser and unit. I have had a faulty circuit breaker trip after a given time but generally within a few minutes. I hope this helps.

[install monkey]

check for water in the isolator too

[install monkey]

so when ur daughters pet hamster nibbles through the supply it get char grilled- teach it not to chew wires again

Why is that?

[Kirky]

Ok guys cheers

But if it was a faulty cap then surely it would trip almost straight away same for water in the isolator surely it wouldn't run for a good hour with no problem cycling on and off at full load quite happily. Something must be steadily getting hotter. After the unit ran for a good hour it tripped breaker and when reset only ran for few minutes so can only think that when I arrived at site whatever's causing the trip had cooled and took a good hour to heat up to the point that it caused the breaker to trip

[stufus]

Megger the comps sounds like one's on it's last legs.
Cheers
Stu

[charlie patt]

if its a b series check the crank heaters if its a c series check the insulated jacket for water around the terminal blocks if its a d series the loom rubs on the eev and on full volts ie after run down its enough to dump the breaker alsowe have been always told tpye c breakers on motor rated we only use type d on heater mats in the c rooms we always fit fridge kit on type c breakers is this correct we have never had any problems ta charlie

[kevin1976]

hi, not sure if you have solved your problem, but we have had a similar problem recently. are the breakers on an rcd breaker? after a couple of visits, and lots of finger pointing, it turns out the sparkys had fed our condensers off of an rcd board. they changed the board, no problems since!

kev

[a/c.nick]

insulation test the feed cable as i have struck that before and it would trip after the cable warms up due to damage from mice

[Kirky]

Second compressor was throwing breaker when I went back to site compressor was throwing breaker straight away must of been getting a bit tight but now is well and truly seized priced to replace. Got the job to repair leak on its sister unit which I did but found a secondary fault restriction causing very low suction pressure switched modes gave reversing valve a knock put back into cooling and unit worked fine for about 8 hrs then stopped again back at zero bar suction fun times