We have a SunStat Pro II 500775 thermostat and a Sunstat Relay II 500810. Installed in April 2016. Used twice and then did not use over Summer. Now the relay is not working at all and the thermostat's GFCI trips instantly when turned on. Nothing changed between Spring and now (Nov. 2016)
Post by btwhitehurst on Dec 14, 2016 10:18:04 GMT -6
Although you may not think things have changed. Things change! You either have a bad thermostat that may be covered under warranty or you have a fault in your wiring. Check your installation manuals on how to check for faulty wiring. Use an OHM meter to test resistance of the leads coming from the heating cables. They should match the correct resistance values for that length cable. Also test resistance from the hot leads to the shielded ground. There should be no resistance value there. If anything doesn't match up you have a short in your wire and it needs to be replace. You can contact your wholesaler to rent a Watts Wire test kit. We at Pexheat.com have rented it to customers many times. Just be aware you need to leave a large deposit.
Brian Whitehurst Pexheat.com Radiant System Design & Sales www.pexheat.com 888-470-2757
I just posted my solution to 500775 problem: cleaned the power module contacts & the cover plate contacts - all is now well. cleaned with electronic cleaner spray & wiped off (not needed unless to wipe dirt away)