Weil-McLain CGM-5 series 7 boiler leaking water at circulator motor shaft

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Old 01-07-12, 07:31 PM
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Weil-McLain CGM-5 series 7 boiler leaking water at circulator motor shaft

[I discovered this forum today, so it's my first post]

A month ago I noticed a slow water drip from the underside of the circulator motor, seemingly migrating from the circulator pump shaft itself; there's no leak at the motor attachment flange surface. I put a bucket under it, and not wanting to mess something up during the holidays visitors period, just let it drip (adding water to system as needed) so to measure the loss over 30 days (15qts lost ending yesterday). Unfortunately, it's now lost another 7qts in the past 30 hours. Also unfortunate: this discovery happens on a Friday evening/weekend when any parts store (if any) is closed until Monday.

Years ago, I'd removed the motor drive assembly to fix something mechanical, but that parts source has moved somewhere else in MSP area and now sells only to contractors. In any case, I dare not remove the motor/circulator unless a) it's during business hours of a local parts source and b) I learn what part (bushing? o-ring?) I'd need.

The Weil-McLain boiler plate reads: CGM-5 series 7, CP No. 628241. The motor plate reads: Bell&Gossett Booster series#100 FY. I've had no luck Googling something like an exploded-view parts diagram for this specific motor/circulator. Would the source of the leak be a B&G part# or a Weil-McLain#? ..so I at least would know what to ask for if calling or visiting a parts source.

I've lived in this house since 1986; I think this boiler is 1980-85 vintage ..and way oversized (140k/100k) for my 1400sf bungalow. Should I also be concerned that the water leak may be washing away the circulator pump's oil/lube? The leaked water is/was a bit oily. In any case, I hope the leak doesn't accelerate in the 40hours until Monday. If it's a DIY fix with a $10 seal/gasket, I'd rather not cold-call a repair service that may insist I replace some entire $$$ unit.

[Topics for another post: 1) I've never been sure how to tell how much oil is enough vs too much in the pump or motor filler caps. 2) Up in the basement ceiling joists, I've got a huge expansion tank that seems to have no relief valve or any way to measure air pressure or how to know if it's too full or empty.]

Duane
 
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Old 01-07-12, 08:13 PM
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Should be able to find anything you need to know about that pump here:

Series 100 Inline Booster Pumps | Xylem - Residential and Commercial Water Systems

Particularly this one:

http://completewatersystems.com/wp-c...11/04/1123.pdf

I think If'n I were y'all, I would think about replacing the whole bearing/impeller assy:

Patriot Supply - 189134

And the motor mounts:

Patriot Supply - motor mounts

Ah heck, it's all apart, might as well throw a new coupler in there too:

Patriot Supply -

I'm pretty sure that you will get some recommendations from the guys here to replace the whole pump with a modern wet-rotor design... let's see what happens...
 
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Old 01-08-12, 10:22 AM
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Thanks for the info. Since my OP, I've found some useful sites for B&G Series 100 pumps/diagrams/advice, such as this B&G video:

Bell & Gossett Series 100 Circulating Pumps and Pump Parts [click Video tab]
^^ scroll down for: $85 Bearing Assembly ($90 w/impeller), $25 seal kit, $2/$6 body/flange gasket.

..and a repair guide:
http://www.statesupply.com/skin/fron...pair-guide.pdf [note seals diagram]

.. and a B&G's parts doc:
http://www.statesupply.com/skin/fron...series-100.pdf

So it seems the solution to my leak is either the whole bearing assembly, or for less cost, just the Seal Kit? (+body/flange gasket). Does the seal kit require special tools to access internal bits (so it's too much trouble)? But IF its seals that are leaking, why replace the casting/shaft/assembly?

I'll need to decide which to order, since I assume I should NOT, out of curiosity, remove my B&G motor&pump from my system until the parts are on hand? (it's still serious heating season in MN)

[I've yet to learn what is a "wet-rotor design"]

Originally Posted by NJ Trooper View Post
<snip>
I'm pretty sure that you will get some recommendations from the guys here to replace the whole pump with a modern wet-rotor design... let's see what happens...
 
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Old 01-08-12, 10:47 AM
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The seal replacement instructions can be found in one of the PDF files at the B&G website I posted.

There are also parts breakdowns as well... probably the same stuff you found at State... there is a service manual at B&G too... again, probably the same files.

You shouldn't need any special tools to replace the seals... don't forget to purchase any gaskets you need if they are not included in the seal kit.

But IF its seals that are leaking, why replace the casting/shaft/assembly?
A couple reasons I can think off...

If it's been slowly leaking for a while, the bearings may be damaged as well.

SPEED of repair... it IS heating season as you say, after all!

"Wet Rotor" ... Taco 00 series of pumps... B&G NRF series... Grundfos... several others as well.

The venerable 007 is used in MILLIONS of installations... pretty much the 'standard' circulator these days, as the series 100 was.

Taco-Hvac: Model 007 Cartridge Circulator

This graphic will show that the 007 can most likely replace the series 100 in almost every single case. The whole pump can be had for about $75 or less. It should be a direct replacement.



Patriot Supply - 007-F5
 
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Old 01-11-12, 06:19 PM
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leak repaired

Well, although I intended to first just try the seal kit renew, State Supply (handily, they're here in StPaul, so no S&H) had only one bearing assembly kit on the shelf (perhaps there were more in back room), so I chose that instead (bird-in-hand etc).

The oiling wicks in the original assembly had disintegrated into mush, so although the shaft bearings seemed to feel (turn) OK (compared to new unit), they likely were lubed with oil+water during an unknown period of recent history ..and at >35 years old, perhaps it deserved new parts.

~> How MUCH oil should be put into a DRY-when-new wicking chamber? The State Supply guy said oil level should not 'fill' the chamber (be below the bottom of the rectangular casting that the cover snaps into). But emptying a B&G tube of oil (the 'recommended' annual service amount) seems to have been entirely absorbed in the initial 'priming' of the wicks; there seems to be no oil pooled in bottom of chamber. Should I add more, to at least have a visible 'oil level'?
 
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