Why is my thermostat buzzing?

June 3, 2011 5:22 PM

I just installed a digital thermostat for the evaporative cooler in our house. Works great, hi/lo, pump, fans, etc., but there is a very low buzzing coming from the thermostat when the evaporative cooler is running. When the thermostat is in "standby" (just showing the ambient temperature) it does not make any noises. It is definitely coming from the thermostat and not any nearby location. Any ideas why this is happening? A defective unit? Weird house wiring? Thanks!
posted by jroybal to Home & Garden (3 answers total)

The thermostat is probably using a physical relay to switch the power to the cooler. The coil on that relay is humming. Though that hum won't affect operation I'd call it defective in this application and would return it for another one.
posted by Mitheral at 6:37 PM on June 3, 2011

@Mitheral: "Return it for another one" as in another of the same make and model, or as in a different make and/or model?
posted by attercoppe at 8:23 PM on June 3, 2011

If you are otherwise happy with it I'd try a straight exchange, it's possible this is a manufacturing defect rather than a design defect.
posted by Mitheral at 10:39 PM on June 3, 2011