Getting code A03 on Carrier 40x when using electric stand-by

[meat guy]

This is my first post. I have a carrier 40x unit with electric stand-by, 6 years old, compressor on stand-by is 3 years old (replacement was $3000). The unit wasn't cooling so, I just had all the lines replaced and the road unit is working perfectly. The electric stand-by has an issue. I can plug it in and it will work fine for 30 or even 48 hours and then shut down, code is A03. If I try to re-start it sometimes it will start right up, other times it will buzz loudly for 30 or so seconds and shut down. I've checked my power cord and conections also checked the power and it's over 240 volts. I've also tried other outlets. and cords. The shop says it's the compressor, again. Why would the compressor work for 40 hours and be bad? Am I looking at another $3000 bill or could it be something else? I plugged it in at 12:00 pm today, and I figured I'd give it another test I set it to 0 and 8 hours later it is holding 2-4 degrees. My guess would be that sometime overnite it will shut down, or mabye tomorrow sometime. When it shuts down I have to use the road unit 1 gallon of diesel every 1.5 hours. Any ideas or advice would be greatly appreciated.

[sonkax]

A 03…Standby / Compressor electrical motor over heat, i suggest checking the overload relay... loose wires or bad contacts inside relay.... try replacing relay before compressor...

[meat guy]

Thanks. I will try that.

[moggy66]

Check capacitors and start relay, if its humming somtimes i would look to the start relay

[IRMechanik]

what voltage is it? Is it single or three phase?

[sonkax]

i suppose it's 3 phase, his from US...

[meat guy]

single phase.

[sonkax]

Then moggy is right,check those as well, remove the start relay cap an see how it,s working, had one case in witch from overheating the moving element inside relay was bendt, causing it to work exactly the opposite way that it should.

[meat guy]

Great information, thanks.

[clivemtk]

what happened did u fix it

[meat guy]

I'm still using it on the road unit when I need to. As for the electric stand-by, I'm taking it to my refrig. mechanic, with the information I've gotten here. I don't think I can repair it myself.