Recent installed Propane Hot Water Tank won't stay lit
I have a State Select water heater. It is about 5 years old. We replaced it 3 years ago with an electric tank and now have decided, I like the propane one better. So we reinstalled the propane water heater.
The problem is, the burner will not stay lit. The pilot light is easy to light and ignites the burner, but the burner will only burn for a few minutes and then goes out, which in turn blows out the pilot light.
We put in a new thermocoupler, but are having the same problems.
It is on a direct vent system, so no draft hood/diverter at the top of the tank and there is a cold draft felt blowing out of the bottom on the heater. I was suspecting that may be the problem, however the draft is not strong enough to blow out the pilot light, when only the pilot is burning.
It is a 40 gallon tank hooked up to a 100 lb tank with a new regulator installed on the outside wall. No other appliances.
When the burner is lit, you can hear fluctuations in it burning.
Is is possible the burner is plugged? Or perhaps incorrect venting? And how important is it to close the door? Will that extinguish the burner?