Hello, Slant Fin Galaxy steam boiler 10 years old.
On release of pilot button flame goes out. Replaced thermocouple, still same results . Tested thermo. by heating tip with propane torch and measuring mv at end of thermocouple. Measured over 30 mv, numbers dropped as it cooled off.
Check continuity of roll out switch - ok
Also, probably more of a concern, found that there is a lot of rust on the panel that is the buffer from the boiler. Haven't taken it apart maybe just a leaking pipe nipple?
Wishfull thinking, opinions please

 

Check the cleanliness of the electrical connection in the gas valve housing where the thermocouple attaches and be certain the nut holding the connection is slightly more than finger tight. If that doesn't work then the most likely problem is the holding coil has died and you will need a new combination gas valve. There are some gas valves that have field-replaceable holding coils but I do not recommend anything but a complete new valve.

I haven't a clue as to what you are referring to. Maybe a picture would help. To post pictures you need to first upload the pictures to a photo hosting site such as photobucket.com or villagephotos.com. and then post the public URLs for the pictures (or album) here. More pictures are always better than fewer. Please have CLEAR, in focus and well lit pictures and have both close up pictures and ones from a far enough distance that we can see how the various parts are interconnected.

 

I am refering to the front inner panel behind the gas valve, the bracket for the roll out switch mounts on it. I'm thinking the 1 1/4" nipple that goes into the lower boiler tapping might be leaking and hopefully it's not a cracked boiler. The panel has a few random areas of rust in assorted places but one area at the lower right on the panel I stuck my finger through it.
Will try loosening up on the thermocouples connection at the gas valve, I tightened it 1/4 turn past finger tight. Thanks for the suggestion.