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Bell and Gossett 100 mystery sounds

Hello there, Long time lurker here seeking your expert advice. I had some awful metal scraping sounds coming from my B&G 100 series pump. It's a hot water baseboard system. I checked for the obvious and found a mangled coupler inside. After carefully replacing the coupler and very lightly oiling the 2 motor tubes, and heavily oiling the bearing assembly, I turned the pump back on.

Now I'm getting a very different grinding sound. Not as loud but still not right. It sounds like there is a piece of metal clanging around in there near the bearing assembly or impeller. I know I pulled the entire coupling out, so it can't be that.

Am I missing something here fellas?


  • Gordy
    Gordy Member Posts: 9,514
    Motor mounts

    You should replace the mounts with the coupling. If you don't the coupling will fail prematurely due to miss alignment from worn mounts. Probably why they failed in the first place.
  • B & G

    The motor mounts may be shot, but they wouldn't be the cause of this new sound so soon. Sometimes a day or two of run time will clear up a dry bearing assembly. Failing that, I'd:

    1) check to make sure the coupling assembly was installed properly

    2) de-pressurize the system and check the impeller for debris.
    Often wrong, never in doubt.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,282

    Are you using 20-weight, non-detergent oil? Did you check the wicking to see if it's burnt? Did you press the wicking onto the bearing with the back end of a pencil?
    Retired and loving it.
  • MitchInNJ
    MitchInNJ Member Posts: 4
    B and G

    @ Gordy. Yes. I will replace the motor mounts next for good measure.

    @ Alan. I rechecked the coupler to make sure the set screws were recessed and they were. Are you saying it's ok to run the motor with that sound for a day and see if it goes away?

    @Dan Yes. I'm using read deal B&G 20 wt oil in the little clear tube. The cotton is in perfect shape in the oil chamber and I probably poured a half tube in there... so much it dripped out the bottom. I will push the wick down onto the ball bearing as you suggested...Could this clangy sound come from an under oiled bearing? It sounds like somebody left a quarter in the dryer.

    Thank you all for your comments gentlemen.
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,282
    Is the sound constant?

    Or intermittent?
    Retired and loving it.
  • billtwocase
    billtwocase Member Posts: 2,385

    If you have a Sids close by, pick up a 156A spiralink coupling. You also should not need to replace the motor mounts if you use it. You will know if it is over oiled, it will leak out. Don't be afraid to put the oil to it
  • MitchInNJ
    MitchInNJ Member Posts: 4
    edited March 2014
    Bell and gossett mystery sounds

    Thanks for the replys. I've now checked and replaced the coupler twice, including the motor mounts, and oiled the chamber utility it leaked out the bottom., but I still have a clanging comming from the bearing assembly.

    What do I do next? Could something be clanging around in the impeller? How can a broken coupler lead to a broken impeller?
  • icesailor
    icesailor Member Posts: 7,265

    New Series 100 circulators have a plastic impellor.

    Very old ones have multi piece metal ones. I've seen them fall apart.

    That isn't saying what your problem is.

    A few years ago, I had a noisy  007 that had been quiet for years. I pulled out the guts and there was a big goober of solder that had flowed onto the volute and the impellor was rubbing on it.

    You never know what it might be,
  • Big Ed_4
    Big Ed_4 Member Posts: 1,724
    edited March 2014
    Motor Bearings

    Was there a large in and out movement on the motor shaft ? Did you aline

    coupling so alan screw tighten into counter sink ? Big you bang on the coulping to fit it on the shaft ?
    I have enough experience to know , that I dont know it all
  • MitchInNJ
    MitchInNJ Member Posts: 4
    B and g mystery sounds

    @ big ed. I wiggled the coupling on to both shafts making sure the set screws got "sucked" Into the countersinks. Backed it out several times until if got it right.

    I didn't check the shaft for in and out movement. Should I? How far in or out should it be? Does this matter?
  • Steve Ebels_3
    Steve Ebels_3 Member Posts: 1,290
    Just a thought

    Instead of wrestling with the old pump you could just take it out and replace it with a modern wet rotor design.

    A BnG NRF22 or Taco 007 are nearly direct replacements from a hydronic standpoint and the flange dimensions are identical.

    In a Grundfos you could select a 15-58 3 speed or a 15-55 Alpha variable speed which will use 60-80% less power and will auto adapt to your systems flow characteristics.

    A Wilo 21 series 3 speed will do the same as the Grundfos 15-58.

    All of these will use less power than the BnG 100 by at least 25%.

    Just a thought.
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