I have a honeywell vision pro IAQ stat #yth9421c1010 on a single stage heatpump with a 2Stage gas back up furnace. when stat calls for aux heat to come on the stat goes blank? any suggestions?
Heating & Cooling - Honeywell - Electronic Programmable Heat/Cool Thermostat - CT3300A100...
Answers & Comments
That sounds like a tstat problem and that you will need to replace it.