I've got a Carrier downdraft htg/fan coil unit, 1990 Model No. 58DRC080-JB.
Unit was working fine. Last weekend main power to the house went on and off about 5 times in 1 hour. Next morning the blower kept running even after the heat setpoint was satisfied (and burner properly cut off). I made the blower stop by opening the access panel to trip the safety switch.
To test for Tstat damage I completely disconnected the thermostat wires - The blower still runs constantly when the panel door closes, so I think Tstat isn't the problem. Heating and cooling both function properly from the Tstat, just that the blower stays on constant; I have the access panel ajar until I want to run it.
Looking at the unit and the wiring diag inside the panel, I wonder if there's an airflow safety switch or temp safety that got shorted out.
Anyone heard of power outage causing a fault like this before?
Thanks in advance for any ideas on troubleshooting, or other advice.
Made the mistake of asking on hvac-talk forums, just for any known DIY sites for homeowners, and within mins, a handful of unfriendly posts and the thread was closed. :huh:
-Mark
Unit was working fine. Last weekend main power to the house went on and off about 5 times in 1 hour. Next morning the blower kept running even after the heat setpoint was satisfied (and burner properly cut off). I made the blower stop by opening the access panel to trip the safety switch.
To test for Tstat damage I completely disconnected the thermostat wires - The blower still runs constantly when the panel door closes, so I think Tstat isn't the problem. Heating and cooling both function properly from the Tstat, just that the blower stays on constant; I have the access panel ajar until I want to run it.
Looking at the unit and the wiring diag inside the panel, I wonder if there's an airflow safety switch or temp safety that got shorted out.
Anyone heard of power outage causing a fault like this before?
Thanks in advance for any ideas on troubleshooting, or other advice.
Made the mistake of asking on hvac-talk forums, just for any known DIY sites for homeowners, and within mins, a handful of unfriendly posts and the thread was closed. :huh:
-Mark