Reliance 606 640YORT Waterheater Question

[Mizmelzy76]

We currently have a Reliance 606 water heater model 640YORT. 70 Gallon Tank. About a year ago the thermocouple went out on it. We tried replacing that first to see if it would fix our pilot light issue (gas water heater). It did we had a little trouble at first still getting it to light but it eventually did with no further issues. It's now a year and a half later and the same issue is happening again. The thermocouple is going out again. The water heater tank said it was manufactured in 2005. Couple of questions. 1. What can cause the thermocouple to go bad in just over a year? Could there be something else going that's taking out the thermocouple? If so what? 2. Is it time to just bite the bullet and buy a new one. We asked a friend who is knowledgeable and has dealt with water heaters before. He said we should be able to get another 5 years out of it. But just want to make sure. We could just keep replacing the thermocouple on it, but feel like we shouldn't have to replace it every year. It should last longer than that.

Any thoughts?
Thanks!
Mel

 

[breplum]

The thermocouple puts out millivolts.
The first thing we check in this type of issue is what is the mV?
That answers the issue of that. If it is bad, we replace the "pilot assembly", not just the thermocouple.
If mV are good, then if there is a problem, it can be the gas control valve.
But, frankly, a gas water heater that is 15 years old, it is not worth the money to fix because its useful life is over.
70 g. WH are expensive as hell. Consider a tankless Navien NPE 240A for twice the life of a tank water heater. (20+years).