Any hope for this pump?

zepfan · October 17

Attached are pictures of a Taco 25 hp FM series pump, for the closed loop of a building. The issue is the pump had had the seal replaced 3 times over the last six years. The one that has just started to leak, was good for three years. When we first started working at the building, it had been un occupied for a while. The pumps were left running, and at some point the seal started to leak. With no one in the building, no one noticed that it was leaking. There is a floor drain directly next to the pump, so there was no water on the floor. How long it was leaking i don’t know, but it must have been long enough to cause a fair amount of rust around the impeller housing.

It appears to me that this wear has caused a slight opening near the bottom of the impeller housing , and that is were these seals start to eventually leak. I didn’t know if there were any other solutions to keep these seals from leaking, with the existing condition of the housing. The pump is from 1988, and is one that Taco no longer makes. The only parts that seem to be available are the seals. Any suggestions would be much appreciated. Thanks to all.

hot_rod · October 17

dirty fluid takes out seals. I see a pot feeder, what gets added to the system.

Does the other pump eat seals?

The seal needs to be a tight fit into the casting, a smooth,in tolerance, machined casting.

If the problem is the casting, a good pump shop can build that up and remachine the bore.

109A_5 · October 17

@Pumpguy may have a good opinion. I have no idea what the expected life span of those seals should be. I would think if the housing is OK and the bearings are OK just replace the seals. The other thing is the shaft may be grooved, maybe there is a replaceable sleeve.

Jamie Hall · October 17

IF it's a two part seal — that is, if the actual sealing surface is part of the replaceable element, and there is a tight (perhaps press fit?) sleeve on the shaft and another sleeve on the housing, with the seal in between, you may get away with the seal.

However, if the seal bears on the shaft, you may have enough damage on the shaft that a new seal will not work. You might be able to machine the shaft, but…

pecmsg · October 17

2 years is a short span. Alinement, water quality, who replaced the seal and were SOP followed.

It needs investigation.

Intplm. · October 17

The replacement shaft seal/seal is only as good as the place you install it.

If the housing and the shaft are pitted or damaged to the extent that the seal does not seat well, this type of leak will occur. If, as you say, the parts are no longer available? I would get in touch with Taco in Rhode Island and get their advice before doing anything else.

SteveSan · October 19

@zepfan Please give Taco Technical Services a call during normal business hours Mon-Fri 8am-5pm EST 401-942-8000 and just ask for Technical Services.

As others have suggested, poor water quality is usually the culprit for seals to leak.

pumpcontrolguy · October 19

When you say you replaced the seal has been replaced 3 times, was it just the seal itself or was the bushing ever done? If the bushing was never replaced, it's probably worn underneath the rotary head of the seal. We basically always cut new bushings when we rebuild a pump.

Also, did you ever take note of how did the seal fail? Did you ever open it up to take a look at the faces for cause of failure? I've attached two PDFs that can give you some idea on actual cause of failure

Failure Analysis for Seals 1.pdf

Failure Analysis for Seals 2.pdf

ScottSecor · October 19

I wish I had these two failure analysis documents when I started in the business. Would have saved many hours of labor and frustration. Thank you @pumpcontrolguy

hot_rod · October 19

https://forum.heatinghelp.com/discussion/comment/1906882#Comment_1906882

that is a comprehensive list of seal failure causes, thanks

pumpcontrolguy · October 19

Happy to share. Shout out to Paul and Pete of Gaddis Co for those documents. They're great guys, both chock full of knowledge regarding mechanical seals.

Any hope for this pump?

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