Need to cross reference potential relay - http://www.hvacmechanic.com/ Forums

Original message

klt

198.8.3.42

"Need to cross reference potential relay" , posted Fri 12 Sep 11:20

I have a Lennox G16 residential AC unit model # HS19-461U-1P and the potential relay needs to be replaced. Starting cap is good, freon is good. Tries to start and about half of the times does, otherwise protection circuit times out and it will try to start compressor again every 2 minutes or so. Information on potential relay is ESSEX 128306-2965TB. Local parts stores do not have it and cannot cross reference. thanks in advance for any help.

Replies:

pipinghot

69.156.110.13

"Re(1):Need to cross reference potential relay" , posted Fri 12 Sep 23:48

A potential relay has a normally closed contact to energize the start winding. After the motor starts, a high voltage induced by the motor activates the relay, and de-energizes the start winding. If the relay is not working, the start winding stays energized and the start capacitor will probably rupture. I would change the run capacitor first.

Jojo98

68.60.207.210

"Re(1):Need to cross reference potential relay" , posted Fri 12 Sep 14:21

Try your local HVAC Service contractor, I'm sure they can get and install the relay in no time.

klt

198.8.3.42

"Re(2):Need to cross reference potential relay" , posted Fri 12 Sep 14:44

I have called about 6 parts stores and the local Lennox dealer. Lennox will only sale to liscensed repairmen and the other places cannot cross-reference the part number. Otherwise I can measure the voltage across the relay windings, remove it, and take it to a supplier to try and get a replacement. A co-worker's brother said to do that or ask for a Hardstart Kit SP10 to wire across the running capacitor.

klt

198.8.3.36

"Re(3):Need to cross reference potential relay" , posted Mon 15 Sep 11:29

Never was able to cross reference original potential relay so bought the hardstart kit, wired across the compressor run cap, opened wire to compressor start cap and everything worked great again.

I had replaced the compressor start cap last year and it was bad again. Bad potential relay was holding the start cap in circuit at all times. Thanks for replies and advice.