Pool losing prime

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Rod1971

Pool losing prime

Postby Rod1971 » Sat 26 Aug, 2017 20:29

My pool is running perfectly for about 2 days and then loses prime. The pressure will start off at about 20. It will stay there for a little and then ]over the next day or so will move down to 15. No visible signs of air in the system. It will stay at 15ish for about half a day and then move down to 10. At this point I will see air in the pump filter. Then it will eventually lose prime. If I shut off the pump and either open the pump filter releasing the pressure or I backwash the pool will prime right back up and last another couple days. I can't find any suction leaks. I spoke to my pool guy and he said more than likely your sand is bad in your filter. Does that make any sense? Any help or comments would be appreciated.

Thanks!!!


Denniswiseman
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 775
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Pool losing prime

Postby Denniswiseman » Sun 27 Aug, 2017 01:51

Rod1971 wrote:My pool is running perfectly for about 2 days and then loses prime. The pressure will start off at about 20. It will stay there for a little and then ]over the next day or so will move down to 15. No visible signs of air in the system. It will stay at 15ish for about half a day and then move down to 10. At this point I will see air in the pump filter. Then it will eventually lose prime. If I shut off the pump and either open the pump filter releasing the pressure or I backwash the pool will prime right back up and last another couple days. I can't find any suction leaks. I spoke to my pool guy and he said more than likely your sand is bad in your filter. Does that make any sense? Any help or comments would be appreciated.

Thanks!!!

It definately seems like a small suction side air leak. Have you lubricated your pump basket "O" ring with silicone grease
Have you tried raising your pool level so that it's 2/3 the way up your skimmer opening
Sand doesn't go bad, it's been around for millions of years, what you could do is Deep Clean your filter to eliminate it from the equation
Rod1971

Re: Pool losing prime

Postby Rod1971 » Sun 27 Aug, 2017 17:34

The O ring has been replaced and lubed and the water level is plenty high. In an attempt to determine if the filter/sand is the culprit I have been running it for 24 hrs on recirculate. The pressure started 18 and and soon leveled out at 16. Another day or so and I should know.

On a side note, I recently replaced the spider gasket and top of the Hayward multivalve. When replacing it I noticed that some of the groves in the valve body were pretty wide and a little chunk was out of one of the side just below and up to the gasket. I epoxyed that and put some sealant in the groves. Seems to be working ok as I don't hear any water draining thru the backwash like I did before when it was on filter. There is a very slight drip from the backwash where the pipe connects to the valve. Could this deteriating valve have anything to do with my pressure loss over a couple days? I ruled it out as it is passed the suction side and figured at most it would drip water and I am not noticing anything around the edge or handle. I think I had my pressure issue around then but not sure it was to this extent.

Any thoughts are appreciated.

Thanks
Denniswiseman
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 775
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Pool losing prime

Postby Denniswiseman » Mon 28 Aug, 2017 03:52

When running on recirculate you are bypassing the filter and have no resistance and no problems unless you connect the vacuum as this puts an extra suction load on the pump
The MPV is always under pressure, even if there was a problem inside you shouldn't be getting air in your pump basket
You could try connecting a vacuum hose both on recirculate and filter and see if that creates air in the pump basket
Normally the only problem with a filter is higher pressure as the dirt builds up and creates more resistance to flow through it. The fact that your pressure is dropping comes back to the pump suction. Remember pump outlet positive pressure, pump inlet negative pressure
Replacing filter sand is a big job and unnecessary (i've been there) but as previously mentioned a filter Deep Clean would be beneficial but would probably lower your clean pressure to start with

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