Losing prime in filter mode.

[jerry230]

Moved from HERE

Anymore info on this problem? Did you ever figure it out? I have the same issue but I have a DE filter and and a multiport valve, but same exact problem. I have done pretty much what you have done as well. Seems like it doesn't loose the prime as quickly right after a fresh DE change but it gradually looses it's prime.

 

[ajw22]

Welcome to TFP.

How long does it take to lose prime?

Please create your signature with details of your pool and equipment.

Post pics of your equipment pad.

 

[robertmee]

I was just about to update my thread.

Yes I believe I resolved it. It was the multi port valve. Mine was 8 years old, and the gasket completely flattened. I'm not sure why that was causing me to lose prime, but after swapping it, have not lost prime in 24/7 running in 2 weeks.

 

[jerry230]

Thanks.

I have been hearing gurgling in my multiport valve and I wondered the same. I just can't understand how this would cause an issue after the the pump? Maybe it's causing an airlock that combined with the resistance of the DE filter is causing the pump to loose it's prime? I am thinking about taking the multi valve out and use a series of ball valves.

Thanks for the info.

 

[Texas Splash]

I just can't understand how this would cause an issue after the the pump?

Remember that in an ideal situation, the MPV seals each chamber completely when in its respective mode (FILTER, CIRCULATE, etc). When you turn off the pump, water should stay where it is. Now imagine that if everything was airtight ad working great, and you were to open any part of your system (pump lid, air relief valve, etc). You break that airtight plumbing seal and water starts to move around. Much like sticking a straw into a glass of water. It will fill with water and stay there if you keep your thumb over the straw. Once you take your thumb off the straw, the water falls. In the MPV, I'm wondering if you could potentially break that airtight seal if MPV has a bad seal/gasket. Your WASTE line is open to air on the other end, so if the MPV chambers are not sealing property, perhaps air is breaking into the plumbing system from there causing some problems. Some speculating on my part, but perhaps.

 

[jerry230]

Yeah, introducing an air block possibly........?

I just backwashed my DE filter day before yesterday. Ran all night at 2000 rpm. In the morning, no current. Barely any water flowing from the jets. Pressure showed 11 psi. Pump had water in it with a few quarter size air bubbles at the top, But looked somewhat static. Switched the MPV to recirculate and large amount of air burps into the pool. Good flow can be seen in the pump as bubbles start vibrating and reduce in size. Switch back over to filter and get flow in the pool again. The filter reads about 12 PSI. Flow stops after a few hours and back to square one. Maybe I'll try and figure out a way to bypass the MPV and go direct to the filter because the MPV's are really expensive now.

It's really hard to get the pool clear when it only actually filters for a few hours before loosing the flow.