Pump loses prime when shuts off

[rcholden]

I have now noticed that when my pump shuts off, it loses prime.
Note that when running, there are NO bubbles in the return lines into the pool.
The clear lid is full of water without any bubbles when the pump in running,
BUT when the pump shuts off, at first everything appears normal but then
a few bubbles appear under the clear lid and then more until the water drains out
to a level just below the top of the little basket inside.
When the pump restarts, it primes itself but obviously not a good situation which
I'm afraid if not fixes will shorten the life of my pump.
What can be causing the loss of prime when the pump shuts off ??

 

[duraleigh]

Welcome to the forum

More than one thing could cause that but the most likely is a pressure side leak. Pump running, do you see any water puddling around your exposed piping or equipment?

 

[pooldv]

Welcome to TFP!

More here about tracking down a leak, Pool School - Leak Detection

 

[rcholden]

Welcome to the forum

More than one thing could cause that but the most likely is a pressure side leak. Pump running, do you see any water puddling around your exposed piping or equipment?

The only water leak is from the multi valve handle but that is much higher than the pump basket.
I tried pouring water from a watering can over the 4 bolt gasket behind the pump basket (after tightening them a bit to see
if that helped) as I had seen in another forum but that didn't seem to make any difference, within less than a minute the air
bubbles started to appear in the clear lid and then more until the water level dropped to just below the basket top.
I could hear gurgling noises either from the pump itself? or the DE filter.
Is it possible that a leak from the multi valve is causing the loss of prime at the pump?
To note the drain bolt on the bottom of the basket has never been removed.
Any further specifics to track this down would be greatly appreciated. I like a good challenge but so far this has me stumped.

 

[mas985]

Is it possible that a leak from the multi valve is causing the loss of prime at the pump?

Yes. It can leak air in when the pump is off.

 

[pooldv]

Ha, well, small plumbing leaks are about the most challenging thing of all to track down. Much easier to track down a giant geyser shooting out of some plumbing somewhere. When I had a 20' high stream of water shooting out of my solar panels I didn't have any trouble finding the leak!

Yes, the leak in the multi valve can let enough air into the plumbing, after the pump is turned off, to lose prime.

 

[Paul-pool]

I have the same problem..... My pump seems to have to prime itself as a bunch of the water has gone down in the basket part. As is fairly apparent I am new to all this, any ideas where I could be having problems from? I don't have a multiport valve I'm guessing?

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