Harold Kestenholz
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
A no 67 can be easily repaired and should be disassembled, cleaned, reinstalled and checked yearly. http://www.roberts-hamilton.com/pdf/430.pdf
