Fujitsu - Split A/C AST30AG

[Warren600]

Just after Christmas our air cond failed (is 9 years old) - the 25A RCD tripped & we could not get it to stay on when the compressor attempted to start. We called a service agent - they said it was due to frogs (three were in the cable entry). They removed the top & side covers for a while - worked ok.

Then the fault repeated, this time they replaced the RCD with a 20A cct bkr & blocked off the entry with iinsulation foam. Worked ok - again for a day.

Third visit last Thursday - another frog removed & filler foam inserted. Worked ok, also ok on Saturday.

Today (Monday) it is very hot & humid. Turned on aircond again. Breaker tripped again. I contacted the agents - too busy, so I took the side cover off again - one frog was in there. Removed & tried & tried. Each time the compressor came in the breaker tripped. I took the lid off & couldn't see anything suspicious, but out of curiousity, I left it off. Tried aircond 15 mins later - worked ok.

I believe the frogs are not connected as they haven't been anywhere near the electrical connections. BUT could there be an open/short cct track in the Soft Starter? Does anyone know what is in the Soft Starter?
I'm thinking of removing it & having a look inside to see if anything is obvious.

[multisync]

Sounds like it's croaked...you may need to be ribbet out and buy a new one..

[croc1774]

lol multisync:D

[monkey spanners]

If the frogs weren't dead then they weren't causing a short.
Could be shunted winding in the compressor, if it is it'll only get worse till it won't start at all without tripping. The compressor needs testing with an insulation tester, preferably just after the unit has tripped to see if it is the cause.

[paul_h]

Check the compressor terminals, very common for them to start to burn out, melt and arc etc. If you catch it early you might save yourself a lot of money. A proper check of the compressor motor insulation with a megger as said above, and a visual on the terminals is needed.

Check the capacitor is in spec. Might be dying so sometimes the compressor stalls, drawing extra current. Really common here to see a faulty capacitor trip the c/b as a lot of sparkies fit a 16a c/b on a FLA 13A a/c. They know the wiring laws so they size the c/b to the mains cable, but don't have a clue about motor start amps, all they care about is using the cheapest thinnest cable for mains, so most use 2.5mm or 1.5mm for a/cs and under size the c/b.

Soft starts don't often cause shorts, they go open circuit. I've never seen a soft start cause a c/b trip.
Check the isolator and circuit breaker themselves too, sometimes they are fault and are the cause of the breakdown, not the a/c unit.
Again, really common here as sparkies love fitting light switch style mech isolators and tin capping for pipe covers not waterproofed at all.

[Mavricks Choice]

Apologize for hijacking this thread, but working on the same model, complaint we have here is the system heats & satisfies the room within approx half hour, though doesn't appear to cycle back in by itself? Have tried running on auto mode or forced heat. A restart fixes the problem until satisfied again?
No fault indications are present? Have checked the indoor coil thermistor which is clean & correctly spaced from the Evaporator.
Any thoughts on this problem is appreciated

Cheers
Mavrick