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at the unit...where thermostat wires attach...jump R to Y...tell me if the contactor stays closed or chatters
did you by pass everything on the y side and send thermostat wire (Y) direct to contactor thus eliminating lps, hps, delays etc...just to start elimination?
I understand but to draw a firm line for direction...did you actually put the Y wire from thermostat direct to contactor
Is the transformer wired for proper input as 208 or 230 depending on present voltage?
And is this single phase or 3 phase
is there a stinger?
I ask because I was called by a manufacturer to troubleshoot a similar situation that I found the wild leg was controlling the transformer.
Once I moved the wild leg from supplying the transformer all was well.
Was the corrosion on the compressor terminals themselves?
well I dont think it is board,
as a test you can run direct 24v to contactor from transformer...no thermostat, no board..nothing but transformer feeding contactor coil..if it still chatters then you will need to look at supply voltage/ground issues.
The beauty of transformer direct to contactor is it takes everything out of equation except 24v start and end.
By your definition..you have tried everything else.
You said you bypassed the entire 24v circuit...so that is eliminated as it still faults
That leaves 230 supply and 24v output...what controls output is the supply.
Bypassing direct to contactor, which is new is not going to ground or cause 24v issue.
So when you say "then what"...I do not know as my next move is contingent on what I find each step of the way.
Right now you are painted in a corner with supply voltage and 24v as suspect..
Have you unhooked loads on the 230 side to see transformer reaction?
Take another contactor...unhook the 24v from the existing..put it to the one in your hand...the loads wont engage as the contactor in the unit stays open...
If the contactor in your hand chatters...it is definitely supply/ground related.
If it does NOT....then you know that there is possible draw from a load affecting the power supply..and remember to check for the wild leg feeding transformer..
also you can remove compressor from contactor and see if fan only still makes it chatter....you can remove fan same way.....right now I would look at high voltage side
Just keep me posted..do not respond to this message until you have info...any response makes the computer system force a response from me...so just wait until you have news...good luck
did you switch the power feed to the transformer once you narrowed this down?
It is now down to power feeding the transformer, transformer ground, unit ground, wild leg.