Stuck ceramic/carbon seal

nelsonnucla

I have a B&G series 100 circulator on my hydronic system. It has been off for the summer and I recently oiled it for the heating season and then turned it on ( no heat ). I detected a slight sound difference and when the pump was turned off the spin down time ( watching the coupler ) seemed awfully short. I removed the motor and by hand turned the coupling on the pump shaft and noticed it took what I would say is more effort and when I released their was a slight "spring back rotation" of the shaft. I drained the system and removed the pump/bearing assembly from the volute and noticed that when turning the shaft, the shaft was turning inside the rubber collar that normally grabs the shaft real tight so that they become "one". The spring was turning on the metal collar ( a metal collar sits on top of the rubber collar ). The carbon was not turning on the ceramic. The slight "spring back" probably came from the compression spring doing a slight unwind?? The system pressure ( 12 lbs ) was holding good and no leaking through the seal noticed. I'm sure with time the shaft turning in the rubber collar would open it up to allow leak through. I replaced the carbon/ceramic seal. Thought this would be of interest to the readers.