This morning, I found the boiler pilot light was out. I followed directions found on a DIY website. I lit the pilot, while pressing the red reset button for 30-60 seconds. As soon as I let go of the button, the pilot immediately goes out. The flame is blue. Is this the thermocouple? If so, what is the average life of a thermocouple? This would be the third time I've had to have the thermocouple replaced... they seem to cease working properly after about 2 year or so. Is there anything else I can do myself before I have to call in the professionals? Thanks.

Is this the thermocouple

At this point I would agree the thermocouple could be defective.

If so, what is the average life of a thermocouple?

5 minutes to 15 years or more. Manufactures do not post how long a thermocouple will last. In my second home the thermocouple has never been replaced and it is 15 years old.

Is there anything else I can do myself before I have to call in the professionals?

Not unless you can replace the thermocouple yourself.

Thank you for answering my questions. I am not a handy-woman by any stretch of the imagination. How difficult is it to replace the thermocouple yourself? Also, being a Sunday, I would like to hold off on calling someone until Monday, during regular hours, to save some money. The house temp. upstairs is 55 and on the main floor is 53. I was thinking of buying a small room heater just to make it through until tomorrow.

Replacing a thermocouple is not all that difficult but you have to have the tools and the knowledge in how to use them. Depending upon the conditions of the weather where you live a small heater might get you by.

Furnace stopped working, pilot out, would not stay lit.

Replaced thermocouple, still wouldn't remain lit. Bought new gas valve and replaced (Honeywell VR8300A4508), installed 2nd new thermocouple, still won't remain lit when I release button.

With button depressed, 2 inch pilot flame hitting top 1/2in of thermocouple making tip glow red hot. Voltage of TC is >30mv not connected to gas valve, and 14mv when connected to gas valve (as it should). In fact, all three TCs read about 30mv open circuit, and 14mv when inserted in gas valve (original, 1st new one, 2nd new one).

Seems to point to bad gas valve, even though the one now in furnace is brand new from PexSupply.

Agree?