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GlacierBrewing
10-02-2015, 01:52 PM
So, I took apart my condensate return pump today because it seems that I had to keep adding make-up water to my boiler. Maybe it's time for a seal replacement. :-)

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TGTimm
10-02-2015, 02:00 PM
Yep.............

GlacierBrewing
10-02-2015, 04:49 PM
Speaking of replacing mechanical shaft seals:
What is the most clever method to install the shaft-mounted mating ring without displacing the rubber gasket?
I am having a very difficult time trying to seat this ring. What am I missing?

Prost!
Dave

Starcat
10-03-2015, 09:36 AM
Depending on the seal type there are different arrangements.
There should be a rubber ring that goes over the motor shaft before anything else. Treat that with silicone spray on install for extra life.
First order, the motor shaft needs to be impeccably clean and smooth. No pitting whatsoever or you can compromise your rebuild.
I go round the shaft with a rotary wire brush, find sand cloth if necessary and often times a rotary polishing compound to finish it out.
Many people assemble MECH seals with some soap water solution. I usually treat the rubber rings with silicone spray and then soap the whole thing when I slide it on. It should be tight but capable of moving on the shaft under dynamic tension from the seal spring when running.
If its a Hoffman, there is a ring in the inpeller housing that may need to be replaced sometimes.
I always keep a spare return pump rebuilt and ready as they have a life span, and different things can push them over the edge.
ON a simplex station there has to be redundancy of some kind when production cannot stop.
Duplex stations are so much better in this regard as the good ones allow you to repair one pump and still have one in service.
Weinmann makes one of the best,
To have your system losing condensate is of course bad as you are instroducing too much raw water which contains to much oxygen that can lead to a major corrosion cycle if not checked with proper maintenance and chemical feed set up. It also knocks your efficiency down as you are adding too much cold water all the time.

GlacierBrewing
10-03-2015, 09:04 PM
Hiya Warren,
Great tips. Unfortunately, I tried them all. Every time I try to seat this rubber seal, it bulges up as I push the ring down. 😫

Prost!
Dave

Starcat
10-04-2015, 06:15 AM
I don't have a clear picture of what you are fighting. Betting you got it solved by now.
If I could see a photo of all components laid out on the bench I may have solution.
All the best.

GlacierBrewing
10-05-2015, 10:59 AM
I don't have a clear picture of what you are fighting. Betting you got it solved by now.
If I could see a photo of all components laid out on the bench I may have solution.
All the best.

Hi Warren,
I'm posting these pictures to the public forum so that someone else can learn from my bumbling.

Here are some pics of what I am attempting to accomplish:
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You can see how the rubber gasket "unseats" when I attempt to slide it all into place down the shaft.
I have checked the shaft for burrs and have sanded with wet extremely fine sand paper, lubed both the shaft and the inside of the rubber gasket. EVERYTIME I try to install this, it bulges out.
Frustrated!

Dave

TGTimm
10-08-2015, 12:49 PM
I just got out an old return pump to check, and I think you may have the seal on backwards. That is, the part you're having difficulty with goes into the backing, rubber first, then the spring rests on the back of the impeller. Was the pump new when you got it, or had someone else possibly replaced the seal and did it wrong?

GlacierBrewing
10-09-2015, 06:34 AM
Hi Timm,
Thanks for the feedback. Nope, not on backwards. It is an older pump for sure. Finally got the mechanical seal installed. Took a pump mechanic and a "Rube Goldburg" setup but, SUCCESS!

Prost!
Dave