It looks like my McDonnell No. 67 low-water cutoff is trying to give up the ghost. (My system overfills with water, I adjusted the pressure downward to see if that helps. ) Any suggestions where to go (I’m in Chicago) for a good installed price from someone who knows what they’re doing? My boiler is a HBSmith G300S, if that helps. Also, any recommendations for replacement vents – most of the ones I have are Dole but I’ve heard that VentRite and others are good. Thoughts? Thanks for any and all help.
A low water cutoff does not add water to a system, it shuts off the burner if the water gets too low. If the system has an automatic feeder wired to the 67, then that might be malfunctioning, or the hand valve to the system might be leaking by. http://www.mcdonnellmiller.com/pdf/install_instr/MM201B.pdf