I have a hot water kick heater under my kitchen cabinets. It seems the heater comes on for 15 seconds and then stops, latter it will do the same thing. Its next to last on the heating loop. Its over an unheated crawl space. I know the kick heater has a thermostat to start the fan and when HOT water is flowing and is hot enough. If the fan was dead or dying I assume it would not start up. Or would only start up if you spun the blades by hand. Did I mention I hate working on kick heaters? I had several at my last house and the fans only lasted 3-4 years or so it seemed.
Ideas? I will use an IR sensor to see what the temp is on the return loop. I assume the temp is borderline, the thermostat turns on the fan, but the fan cools it down enough to shut off the fan. I cannot remember if the thermostat is before the fan area, or in the middle of it.
I have just started to insulate the piping for that loop in the basement. At least all the piping before the kick heater. In the past I was not too worried about heat lost to the basement as it warmed it up a bit, so I would not be too cold in basement workshop. I will get into that crawl space and see if everything is insulated there also.