Indirect Water Heater Leaking

I have an indirect water heater that is leaking from the part in front that monitors the temperature, I think it is called the well. Does this indicate that the unit is shot? Can I replace this part?

2 years ago, my Ultra Super Stor ( I can't remember the correct name at the moment) 45 gallon unit started leaking from the thermostat well too. It was a replaceable item I bought at Blackman for about 45 bucks. The original had a bad weld or braze joint in it, but the new one was an improved 1 piece unit. It took LOTS of force unscrewing it from the tank, and I feared the tank wall would twist and break, but it came out and its been fine since. the (stainless steel) tank has insulation and a plastic jacket over it, so heating it with a torch was not an option.

If the tank has a non-welded thermowell, then it should be possible to replace the thermowell.