I recently had to replace the timer (intermatic T104) in the pump control box, which is an Abco FP-100. Everything has been working fine for over a month, but I noticed the pump did not kick on when the temperatures dropped below freezing. I checked all the connections and wiring in case I missed something when I replaced the timer, and everything looked good. I took the thermostat out of the housing and put it in the freezer, and it checked out fine with a meter. You could here the switch click on and off has the set point was changed.
Last night I set it at the max setting, about 48 degrees, but the pump did not kick on at all, even though the temperature was in the mid 30s this morning.
Today, I put a bag of ice on the sensor, the pump did kick on when I had it set at 44 deg, if you turn the dial down, it would kick off around 34, a 10 degree span. Also the relay had a slight buzzing or humming, but that might be normal for AC relays, I am not sure. So everything seems to be wired correctly and working, just the sensor is not turning on at night when it is colder
Since I live in Dallas, there aren't too many nights where the pump will need to run at night during the winter, but I will be travelling some in January and February and want to make sure everything will work.
I have the sensor set at 45 for tonight, it is supposed to get down to around 36.
Is it just not cold enough to trip the sensor? Or is the sensor defective?
Also, is it normal for the relay to make a little bit of humming or buzzing sound when it is on?