I just replaced a thermocouple using a Honeywell standard Thermocouple for a Genesis boiler and everything seems to be working fine. My concern is that I see a flame both at the end of the thermocouple and the base of the thermocouple.

I own a three family and thus have three boilers one of which the thermocouple was replaced a few months ago by a plumber and the same same situation is happening on that boiler. Thus I assume it is OK or the plumber would not have left it that way.

On the boiler where the thermocouple has not been changed, I only see a flame at the end of the thermocouple.

Should I be concerned?

Is this a thermocouple or a thermal generator? If it is a thermocouple it should not have a flame at the bottom. It is possible that in installing the thermocouple you moved the gas connector enough to cause a small gas leak. Check and see exactly where the flame is and if it is a fitting leaking you need to get it repaired because it can cause some problems... it may not be dangerous but can cause things not to work right.

If it is a thermal generator then it is possible that the generator is not pushed all the way into place and letting some gas ignight at the bottom in either case it need to be made right.

It definitely is a thermal couple so I probably loosened the gas connector as you said.

Thanks for the quick reply