Aqua Hot runs 30 seconds then shut down
Aqua Hot 650D
When burner switch is turned on green light comes on.Unit fires and runs clean. After 30 seconds or so green light dims and burner shuts down and green light goes out. If i turn off then back on the cycle repeats.This happend a few years ago on a long distance trip and would do this cycle thing when we got parked but would start working ok later in the evening.
Last week i decided to try to get to the bottom of it so replaced filter,nozzel,set electrodes and still the 30 second run.I also used a fuel can to confirm fuel.
I bridged the thermostat and replaced the flame sensor with same results.
I have to think the green burner light dimming and going out is a clue.
Any thoughts? It seems if its running it would stay running unless something tells it to stop?