A. O. Smith FPSH50 won't stay lit

[mosleyh]

Woke up to lukewarm water this morning.

I have an A. O. Smith FPSH 50 gas water heater that may be up to 10 years old.

If I power cycle the exhaust blower, it will start, the water heater will light, stay lit for about 30 seconds, then shut off.

The blower then completes its cycle (about another minute) and it shuts off too.

Any idea where I should start trying to troubleshoot this?

Thanks in advance.

[mosleyh]

Cleaned the thermocouple and pilot with compressed air - all better now