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Old 03-25-2021, 10:30 PM
ernst ernst is offline
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Quote:
Originally Posted by ndutton View Post
It has happened before . . . .

This also speaks to the importance of keeping the face plate gasket thin.
Wow! That's sure more than a few thou!

I have a fruitful day behind me. I think you nailed the problem, it was at the very beginning. And, embarrassingly, it is possible that I messed it up myself...

But, do let's start at the beginning. First, I sanded the inside of the pump cover to make it nice and shiny, can't hurt. Then I did exactly what NDUTTON said, make sure water flows freely from the strainer. Well, it did not. I had the bad idea of sucking on the hose -- and got a mouthful of antifreeze. I got slightly wiser and used a small utility pump to suck on the hose but still no water.

Then I looked at the installation and noticed something which may be crucial. A long time ago (15 years?) I installed a nifty contraption that makes winterizing the cooling system very convenient: I installed a T that feeds into the strainer, with one input the seacock and the other a hose that I can put into a bucket with antifreeze. I put a valve in this hose which is usually closed. To winterize, I open the valve and close the seacock and the raw water pump sucks the bucket empty. Winterizing done!

What I now noticed is that I put this contraption (valve and T) just above the strainer (because it fits there...). I realized the top of the strainer is exactly at the water level, and the inlet of the pump is just below that (less than an inch). Now I wonder whether that is carefully designed to be that way. The problem (if it is one) is with my patent winterizing apparatus I have now several feet of hose an inch or two higher than the water level.

I have never had a problem with that but could it be that for some reason, this hose always remained filled with water EXCEPT for this winter, when the hose fell dry for some reason and therefore the pump was not primed? I thought I had excluded that possibility because, as I wrote in an earlier message, I had attached a hose to the pump inlet with its other end in a bucket of water that I held above the pump, and it STILL did not work. What I had NOT done, however, was to fill this hose with water! Since the pump is not self-priming, I suppose this 'test' was not really valid.

In any case, what I did today was to bypass the whole winterizing shebang and attached the hose from the seacock directly to the strainer inlet. Indeed, now the pump inlet was just below the water level. And water did flow when I opened the seacock!

Well, the rest was easy. I installed a new impeller (Globe run-dry) and gasket and turned over the motor. Water came out of the pump outlet immediately. I connected the hose to it and the motor was cooled just as it was supposed to be.

So, was that a major blunder that I committed with my clever (??) winterizing system? Should I be thankful that the problem occurred when I was safely in a slip, and not in some critical situation?

Or is it OK to have that hose above the waterline?

BTW, since I had brought all the tools I thought I might need, including a caliper, I did measure the old and new impeller and the pump cavity. The results were a bit surprising (to me). The new impeller measured 21.95mm (I find mm easier to use for this purpose, others may disagree) and the old one essentially the same, the caliper showed 21.93mm. This is rubber after all so I guess this difference is meaningless. But I was surprised by the depth of the pump body which I measured as 22.25mm. So it is about 0.3mm larger than the impeller. or a bit more than 10 thou. I was expecting it to be smaller. But the pump is pumping like a champ so I won't complain

Do you think I solved the problem? And should I do something about my winterizing system?

Thanks!
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