ac contactor replacement and run capacitor discharge

8043 Views 4 Replies 2 Participants Last post by rheems88, Apr 28, 2009

rheems88

Discussion Starter · Apr 27, 2009

Hi all,

I have a rheems ac unit. I am thinking of replacing my ac contactor on the condenser outside though it is still working fine (been there almost 9 years). I understand I must cut off 240 volts and turn off thermostat for it before I start.

My question is whether simply use insulated pliers to pull off all the wires to the contactors (lines and terminals) is good enough ? As on the terminal side, it has connected to a run/start capacitor or should I discharge the cap first before working on the contactor replacement ?

If need to discharge cap, can I do it with all the wire-in-place using a big insulated screwdriver or I have to disconnect the wire first ?

Thanks all so much in advance.

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Yoyizit

· #2 · Apr 28, 2009

rheems88 said:
replacing my ac contactor on the condenser outside though it is still working fine (been there almost 9 years).

At rated current, if the voltage across the closed contacts is less than 30 mV they're good. Above 100 mV, bad.

If need to discharge cap, can I do it with all the wire-in-place using a big insulated screwdriver

Don't short it with a screwdriver. Grainger sells a 15k, 2w resistor for this purpose. Buy one at Radio Shack.

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Yoyizit

· #4 · Apr 28, 2009

rheems88 said:
can I not touch the cap at all (simply remove the connector and replace the contactor and put the connector back) ?

thanks again.

Yes, just tape over the cap terminals if there is a chance of touching them.

You know, anytime you mess around with something that's working [or not] there is a non-zero chance that something else will stop working, either because of operator error [like dropping a conductive tool into the works] or because of some baffling problem that suddenly springs up and that may or may not be related to your work.
I wouldn't mess with this unless you are having a problem, especially not if your relay contacts pass muster. Monitoring parts health is less risky than replacing parts.

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