matti
New Member
My American Standard Silver system was installed 2016. I lost 24 V XFMR (primary open), got a new one and heater worked. Switched to cooling from thermostat and same XFMR failed immediately. I though that maybe control board is is defected and started to change new. Existing board is 50A65-475 and found 50A65-5165. Just noticed that I can't use that as my board has CIRC-COM and COOL-H terminals which new board doesn't have. HVAC system has two fan speeds: slower speed for heat and higher speed for cooling. Any suggestions?
