Problem with new water heater

I installed a new 50 gallon water heater yesterday and I now have a recurring problem with the unit. I can light the pilot and fire up the burner for about 5 minutes. After 5 minutes, both the burner AND the pilot light go out. It is easy to relight however, the same thing happens again and again. The unit is an A O Smith (propane) 50 gallon with Piezo ignition. I can see the thermocupler glowing. Have you any ideas as to the nature of my problem? Thank you.

Sounds like it's starved for fuel

Are the shutoff valves open? Did dirt get into the fitting? Bad pressure regulator?

Hmmm, I have a new pressure regulator on my 500 gallon propane tank. There is a another (old) 50 gallon water heater installed right next to the new one and the old one works fine. All other gas appliances work fine throughout the house. I simply replaced an old water heater with the new one. Same brand, same size, same everything. Could there be a problem with the high temp thermosat? Maybe something shutting the unit off due to a false temp reading?

Is this located in a closet for chance? It might not have enough free air flow. Many (all?) new heaters can get plugged with lint or dust much easier than the older ones. Is it possible you have a cat or dog and dog hair or dryer lint got sucked into the air intake and block it partially? My unprofessional 2 cents...

a.o smiths are junk

you might have a high limit in the gas controll valve thermostat that is giving you trouble..

all you can do is get a new one for free from the dealer you got this unit form.

but remember you are messing with propane and it is a little more of a problem and more lethal than nat gas...


also if this is one of the new style units "sealed combustion" you might want to be sure that the screen in front of the unit is clear of debris too..


best to change the gas controll t-stat and see if that takes care of the problem......

The heater is installed in the attic. The attic is quite large so airflow should not be a problem. I'm going start by replacing the high limit switch. Hopefully this will eliminate my problem. Thank you all for your relpies and suggestions!