Basic Question, I feel dumb asking

[rucomfy101]

A couple suggestions:
1. Check compressor winding resistances and compare to known good
2. Intermittent voltage drop in circuit
3. Saw something like this before, intermittent logic fault in CLO board would cause compressor contactor to chatter severely. Parts laying in compartment as you stated would appear that the chattering got worse than the one I worked on. It was not a pretty sight but I did see it occur. Replaced the CLO and contactor OEM (94 rated amp)
all good. Sounds like a 48DJ, with the 06 semi on the filter access corner side.
Try a new CLO when you replace the CC and double check the OEM recommendation for RLA.

[coolerguy]

Maybe I should clarify my line of thinking with a question to Coolerguy. Did you put a 40 amp in because you didn't have a 30 amp or did you feel that the unit was drawing more amps than the 30 amp could handle and that was the cause for the meltdown?

I wanted to install a higher quality (if thats even possible) all I had in a square d was a 40 amp..it only runs about 15 amps +/-, and is properly fused.

[coolerguy]

single or three phase ? What did disconnect forks look like ? Is time delay the last device before contactor coil?

It is a 3 phase, however as you know, most carriers only break 2 legs and the 3rd is wired hot. The only time delay, is the thermostat, nothing else is present after that. Knives looked good in disconnect as well as wiring to terminals, no burnt wires..

[coolerguy]

Have you tested the CLO?

Pull low voltage off term 3. CLO should trip. Check by measuring 24v across term X and term 1. Then put wire back on term 3 and check voltage at term 3 and term 1.

Yes I have tested it, worked properly while I was there.

[coolerguy]

A couple suggestions:
1. Check compressor winding resistances and compare to known good
2. Intermittent voltage drop in circuit
3. Saw something like this before, intermittent logic fault in CLO board would cause compressor contactor to chatter severely. Parts laying in compartment as you stated would appear that the chattering got worse than the one I worked on. It was not a pretty sight but I did see it occur. Replaced the CLO and contactor OEM (94 rated amp)
all good. Sounds like a 48DJ, with the 06 semi on the filter access corner side.
Try a new CLO when you replace the CC and double check the OEM recommendation for RLA.

Compressor did check out ok with mega ohm, voltage ok while im there, thats not to say something doesnt change while im not there. Hmm you got me thinking... If it happens again I think I will change CLO.

[coolerguy]

HP,AC, or gas pak?

30a seems kinda light

what was start up A?

It is gas heat and a/c. LRA.. be honest I overlooked.. my bad.. RLA was 20, actual running 15.

[coolerguy]

I have been getting a rash of bad contactors recently. They run for a week or two then the coils get weak and start chattering. I am actually replacing one on Tuesday. I got two from Trane on brand new DX systems and one from Baker Dist. (all three replaced at no extra cost or hassle Thank you to both companies) all this month. Might be a common coil maker being used by several contactor companies. Copper is getting expensive you know.

I did think of this too. I just bought my stock about a month ago, time will tell. Although customers dont want to hear that.. Always the techs fault.