Circulator Pump Problem

Yanks2009

Hi Everyone,

I posted this question on the main wall, but figured I'd also post it here b/c I have a steam boiler.

I have a steam boiler that feeds steam heat to radiators on the second floor of my house and a hot water baseboard loop on the first floor of my house. The system is on two zones (there is a thermostat for the first floor to control the baseboard and a thermostat on the second floor to control the second floor radiators).  I have a Bell & Gossett circulator pump which feeds the loop.

Recently, the B&G pump has been making a loud rattling noise.  I also notice that it is not pumping much hot water into the baseboard loop.  Only part of the loop is getting warm.  Meanwhile, the radiators upstairs have been getting hot with just the first floor thermostat on. 

A couple of weeks ago I had to cut and re-solder a pipe on the loop. It is possible that I introduced air into the system which is creating the problem.  However, for about a week following the work I did on the piping, the baseboard heat was working fine. Also, I  tried to bleed a vent on a hot water radiator connected to the loop (which appears to be the highest point)  to let some air out of the system, but it hasn't helped

Does anyone have an idea what the problem may be? Could it be that the pump is dying?  Thanks for your help.

BobC

bad pump?

I really don't know a lot about these pumps but I did find this video from B&G that might give you some information. They are showing larger pumps but I should think the failure modes are the same. how old is that pump?



That pump may be at the end of it's life but I winder if you can rebuild them. i used to rebuild pumps at my old job but they were not used for hot water circulators. Get the pump model and do a search to see if they offer a rebuild kit.



Bob.

Yanks2009

B&G NRF-22

Thanks Bob.  The pump is a smaller model, B&G NRF-22, which is supposed to be maintenance free and therefore isn't meant to be rebuilt.  Given that these pumps aren't that expensive, I may just try replacing it.