B&G 100 series body replacement advice

OnespotTwospot

hi everyone, first time poster.

I have a B&G series 100 AB circulator pump. It seizes when I tighten the bearing assembly into the pump body. I cannot turn it over by hand or by the motor power. When powered on I can hear the motor clicking unable to turn over however the components spin freely when not attached to the body.

Inside the pump body it looks like the head of the impeller is biting on the some part of body causing the whole assembly to lock up when I tighten down the bearing assembly.

The job was to replace the bearing assembly and the impeller. Both are now new.

I'm thinking about replacing the pump body however that part is very costly. So before doing so I wanted to see if there's anything can do to avoid a body replacement.

I can't see why a bearing replacement would cause something like this.

Cheers everyone

hot_rod

It might be better to upgrade to a wet rotor style circulator. Are there zone valves on the system?

It sounds like a tolerance issue with the parts you have. Is there rust build up inside the pump body, called the volute?

OnespotTwospot

This is a photo of my pump body

hot_rod

Looks like a bronze body pump, this is a heating system? That is a very $$ pump to replace. An iron body would be sufficient for heating use.

There is a gasket that goes between those pieces, probably spaces the impeller, did you replace that.

Sully1266

I agree with Hot_Rod that gasket is very important to maintain clearance for the impeller to clear the volute section of the pump body. Did you replace bearing with the red bearing assembly for a BG 100. I have seen issues when mixing bronze BG housings with Red bearings you think it would be same manufacturing but one is for heating other is for potable water so I’m sure there are differences. From your pic area where gasket sits looks pretty clean replace that gasket and don’t crank down too hard on bolts see if you can spin it by hand with clutch connected to get a better grip.

Sully1266

After taking a better look at your pictures you definitely have to replace body where you put arrows you have lost the round slot plastic bearing wheel spins in it looks to not be perfectly cylindrical for the bearing to spin freely. A iron body BG 100 housing (red) would be much more cost effective then the Bronze. I would say replace whole pump with a cheaper pump but if motor is ok and you already purchased a new bearing pump body would basically give you a new pump at this point.

Sully1266

Sully1266

Wow just looked up price of body 400 plus Crazy I used to have spare bodies in the back of my truck that just got in the way, above is the way volute should look compare to your pictures that’s what’s binding you up. 

Erin Holohan Haskell

@OnespotTwospot, welcome to Heating Help! I've merged your duplicate posts into one here to prevent confusion. Thanks.

OnespotTwospot

Sully1266 said:

After taking a better look at your pictures you definitely have to replace body where you put arrows you have lost the round slot plastic bearing wheel spins in it looks to not be perfectly cylindrical for the bearing to spin freely. A iron body BG 100 housing (red) would be much more cost effective then the Bronze. I would say replace whole pump with a cheaper pump but if motor is ok and you already purchased a new bearing pump body would basically give you a new pump at this point.

Yes, there is a new gasket. The new bearing assembly and impeller are the appropriate bronze replacements (they were costly too, 189034LF).

The question becomes the price of a new cheaper Red pump vs the cost of a bronze pump body which basically gives me a new setup.


I used the bronze model due new oxygen introduced, heat, and water quality concerns. This pump is attached to the bottom of steam boiler circulating dirty water to a heat exchanger for heat to closed loop radiant system.

Sully1266

I would try to clean up and file area of body that’s irregular to get bearing to spin freely normally wouldn’t recommend that but being your pumping return water from a steam system there is sediment in that water already. Look at picture I posted above as a reference to what it should look like. If you can get piece of metal that’s holding up your bearing you may save yourself a lot of money.

OnespotTwospot

Sully1266 said:

I would try to clean up and file area of body that’s irregular to get bearing to spin freely normally wouldn’t recommend that but being your pumping return water from a steam system there is sediment in that water already. Look at picture I posted above as a reference to what it should look like. If you can get piece of metal that’s holding up your bearing you may save yourself a lot of money.

I will try this and post back

jerryb46

try to double or triple gasket and don't over tight the bolts, think about upgrade .

pedmec

have you checked the impeller to make sure its the same depth. try using the old impeller if you can. if if the old impeller works then you know what your issue is.

OnespotTwospot

I found a fix. The issue turns out to be the new bearing assembly (Part no 118431LF) is not the same as my old part even though the catalog shows they are (Part no P86093). They look identical but the shaft length is slightly longer on the new one like a 1/16 of an inch which makes the difference when assembled. This is what was causing the seizing not the impeller as I originally thought.

I ended up removing a support washer and using a double gasket to create extra space inside the pump body. The washer is on the shaft between the spring and impeller. I am guessing that will cause a problem eventually. It was very thick (probably for good reason ).

Working backwards using the old bearing assembly I put on the new impeller and everything moved freely when attached to the body. Thus realizing the issue is the new bearing assembly.

Any idea what removing the washer will do?

Thanks for everyone's input.

hot_rod

I think it keeps the end of the spring from digging into the plastic impeller, maybe