Home heating question
 

I have an old home with natural gas steam heat. The boiler is about 15 years old and works fine. However, since living in the house for about 8 years, I have had to replace the thermocouple now 4 times. Frankly, it is cheap and easy to do but this seems to be a little more frequent than it should. Does anyone know what could be causing this?

You need a gas valve. Make sure the t-couple is engulfed in the pilot flame and the pilot burner and orfice is clean. Also modern t-couples aren't very good.

Make sure the pilot flame isn't too large.
Too much heat will bake them in a hurry.

Could be what Bill said. If the pilot flame is large or lifting it could shorten the life of the thermocouple.
One other thing you can do is get a heavy duty thermocouple not the basic one that Home Depot has.