Hi. I recently made a repair on my Hayward H100ID above ground heater. The thermistors needed replacing as one broke its connection. I tried starting it up, following the startup procedures on the inside cover. Everything seemed to be going fine, but when I came back in a few minutes there was no heat (fan was still blowing). I shut it down and went through the startup procedure again. Sure enough, I got it running, could feel heat comnig out the vent, but in a few minutes it was off again. We had someone look at it last year as it was starting to do this near the end of the season. The only thing he said was our pool has to be full. Well it is so that is so not the problem. Does anyone know a cause for the heater to keep kicking off? We got enough propane. Thanks.