Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

B & G 100 circulator

JIMBO_2JIMBO_2 Posts: 123Member
What might be the anticipated life span of a B & G 100 circulator, if oiled at regular intervals?  The one I am looking at is on a hot water, gas-fired, Weil Mclain boiler with a single loop of 3/4 fin-tube, installed in October 1978.  Just curious.


  • Empire_2Empire_2 Posts: 2,343Member
    Hey Jimbo?

    Well to answer your Q:?  I have seen them last,..In your case that would be a record in my book, but in the same token, have seen them fain due to lac of lubrication, cavitation problems, worn motor brackets, ahhhh ETC.  What ever you're doing keep it up.  Mostly any problem with BG-100 and similar open style pump is due to lac of Maintenance.  

    My $.02

    Mike T.
  • TimcoTimco Posts: 2,928Member

    Sounds seriously over-pumped. It takes very little pump to move water in a closed system. I have swapped series 100's installed in the 40's. Very common to see them that old and working fine. If it goes, put in a 15-58 grundfos or equiv.

    Technical Support Manager, HTP Comfort Solutions.
  • Yep, what Tim said......

    However, newer units I've seen fail within a couple years even with proper maintenance.  The older motors are physically much heavier and the old bearings a much better material.   I've seen older 100's go for years without any maintenanace and still last forever.

    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert

    Noisy Radiators are a Cry for Help
  • tim smithtim smith Posts: 2,282Member
    Single loop, monoflow my guess?

     Depending on how many feet of baseboard and if it is a monoflow, may not be over pumped. We have series 100 pumps running from the 50s and still going. They are generally lower head pumps with high gpm than equivelant cartridge pumps. Will outlive cartridges by 10 fold if oiled once in a while and couplers and motor mounts replaced every 5 yrs or so. Cartridges are cheap and easy and we use them alot but the old B&Gs had their place. imho, Tim
  • HDE_2HDE_2 Posts: 142Member
    edited December 2009

    Depends on system

    The 100 was/is a fairly flat performance curve pump so depending on where the system requirements/performance is, just as many times a small wet rotor is a perfect replacement, other times is brings on other problems.

    For example, remove a 100 from a system with 10 zone valves and put a wet rotor capable of covering all which may be a 26-99 on medium speed and when only 3 zones or so are open, it will squeal.
  • JIMBO_2JIMBO_2 Posts: 123Member
    I see your point

    This building is attached to a similar one, and together there are 4 Weil Mclain CG a (I believe) boilers which came with the B&G 100.  Since 1978 they have been oiled fairly regularly.  But one at a time the B&Gs have gone bye-bye.  One was replaced 15 years ago with a new B&G 100 (red so you can see it was replaced).  The last one to go was about 2 years ago, and I replaced it with a Taco 007.  The impeller on that one was full of a silty substance which I believe brought it to a grinding halt.  Perhaps the system should have been flushed from time to time?  There are 2 original B&Gs left, but I think one is about to give out, because from time to time it sounds seized, I hear it try to click in but it sounds as though it cannot spin.  Perhaps it too is full of silty stuff.  I will have to check.  If it is, then it will be replaced with a cheaper circulator . . . last time I checked the B&G 100 was about 200 bucks.  I now have 2 B&G circulators in the basement and believe it may be time to rebuild then to go another 30 years.
This discussion has been closed.


It looks like you're new here. If you want to get involved, click one of these buttons!