Our heater is working because the house is not too cold. We cannot adjust the thermostat manually. The red light goes on but we can't move the temperature higher or lower. We had a power surge a few days ago and since then we have had a problem. A repairperson is coming today. I would like to have a little information about a possible cause.

Thank you!

Couyld you tell us what the repairman did or said about your problem? Is your thermostat a 24 vdc unit and does it have a battery backup?