I have a 40 gallon gas American Standard hot water heater and the pilot light will not stay lit. I can light it and it WILL light for about 10 minutes and then go out before heating up the water past luke warm. I can relight it again and go through this process several times before the water is warm enough to take a shower in. The thermocoupler assembly has been recently changed and still no luck. Haven't found any sort of switches on this thing to replace, so, am stumped... Anyone got any ideas?

Taking a chance here, open a window on a lower level, relight the pilot and tell me if it stays lighted for a full heating cycle? Could be backdrafts

Does water heater have a closed combustion chamber? In other words, is there an air filter anywhere that could need cleaning?

Make sure Thermocoupling is directly above flame. Also, make sure side in-take vents are not obstructed. Take shop-vac and vacuum them to remove dust and lint. Last, make sure exhaust vent is not obstructed.



How old is the water heater ? If less than 5 years, you could claim it with American Standard.

Hope that helps

Milo