Bell and Gossett 100 original chewing metal, but sealed on wet side

wcs5050

Customer wants to replace pumps connected to ~60 year old boiler with no isolation valves. I'm afraid draining down for pump replacement, and then a cold water refill will shock this thing to seal leakage/failure, never mind the other antique devices connected. I'm not going to own this beast. Of course he doesn't want a new boiler.
It sounds like B&G cooling blade is chafing the cowling, and it's throwing a lot of shavings. It is sealed on the wet side, and is circulating fluid/heat, but making a racket.
If these weren't connected to a 60 year old block, I would never consider a repair.
Does this sound like anything obvious to someone?
Thanks for your comments.

JUGHNE

For me I have found that the motor/pump coupling can come apart or be loose on either shaft , still work and be noisey as hell. New couplings AND motor mounts have fixed this for me before; without cracking the wet side.

wcs5050

Thanks JUGHNE. I've only removed, never dismantled these. It seems like the coupling would wear out, and that has to be what's flapping. I'll check the mounts too (if I go back).

JUGHNE

Too much oil softens the mounts, the motor settles down and the coupling, (universal joint) has to deflect to much with each RPM and wears out. I have not had always had good luck fixing anything on the wet side as most were about the age of what you're dealing with.

wcs5050

I will advise if interest is shown on repair. I'm sorry to say it feels like a walk away.

DanHolohan

The coupler is broken, probably because of the sagged motor mounts. I once saw a broken steel coupler cut right though the aluminum bearing assembly on this pump. The motor was hanging in space on its wire and the coupler was still spinning. Tough guy.

billtwocase

Best coupling to use is a Spiralink style on these. Motor mounts are not an issue

DanHolohan

Very true. Lasts forever.

icesailor

billtwocase said:

Best coupling to use is a Spiralink style on these. Motor mounts are not an issue

Mostly, they are not the issue. But when they are, it's hard to tell that they are bad. Its the rear/end one that is the problem. It throws the motor out of alignment, and allows the end of the motor to osculate in its axis. Do NOT use a coupler with plastic drivers. If the rear mount is bad, and the barely discernible vibration sets in, the springs will cut through the plastic universals like butter.

B&G's are easy. Unlike Taco where the spring coupler preloads the bearing and the seal. Just remove the coupler from the bearing assembly shaft, remove the motor, then the coupler. Replace the coupler on the motor first, slide the motor and coupler on to the bearing. Tighten the set screw, and let her rip.

If its 3 phase, make sure that the rotation is correct. The motor side of the coupler is supposed to have the springs PULL the pump side through its axis. Not PUSH the coupler like it is now that causes the vibration. Its because once the springs break, it is pushing it through its axis.

Easy fix.

HEATON

mounts are the issue!!!! over oiling and age cause sagging and miss alignment, spiralink lasts longer yes but eventually will fail! easy to tell mounts culprit by lack of obvious non symmetrical .. the are easy to change out and cheap " who said do it right or do it over"

billtwocase

I guess I should rephrase my comment. The motor mounts are why the 4 spring couplings break. The one spring coupling will not, due to the sagging front mount. The mounts are an easy change out, but and old motor should just be replaced, or just use a forgiving coupling as in Spiralink style

Tinman

I set up this old Series 100 in our shop just last week so my apprentice could practice servicing this pump in a controlled environment without pressure. Of course, it's a bit different on the job without valves but he's already been taught how to purge air. If you go to Bell & Gossett's website, click on documents, type Series 100 into the Search box, one of the files that populates is a great step by step instruction manual on how to do complete service on the 100 pumps.

wcs5050

Job was a liability besides pump. Recommended he try someone else.

Paul48

Stephen.....Try YouTube......Videos of series 100 rebuild.