Pump Losing Prime - Just Started Happening

MBinTX

Member
May 25, 2024
5
Katy, TX
Pool Size
25000
Surface
Plaster
Hi Folks,

First time pool owner here; this is my first full summer of owning. Learning lots from this forum - thank you!

I have a new situation that has just started happening. I have done as much reading/troubleshooting as I can, but have hit the wall.

What's happening is that my VS pump will switch on and build prime at high speed after ~30 seconds. One primed, it drops to lower speed, and loses the prime after a few more seconds. I can see the pump strainer emptying out via the window; some water does come in but not enough to keep up.

Through a series of experiments, I think I have identified the problem lies on the suction side of the system, either from the floor drain or the skimmer. I say this because if I switch the valving to the spa (shared pump between both bodies), everything works fine. Similarly, if I turn the suction to the spa, but the discharge back to the main pool, everything works fine there as well (other than draining the spa). So it seems the pump, filter etc. are working ok.

During my efforts, I found that I have a device called a "Paramount MVFuse" which the Internet tells me is a safety device for the main floor drain. I pulled out this device and found the magnetic pin had dropped, which I reset. I also found out it has a strainer basket underneath. I had no idea this basket existed, and found it completely full of 20lbs of acorns from my neighbor's live oak tree!

I did clean this out, and when I went to replace the MVFuse, I found the O-ring around it would not stay in place; probably it stretched over time. Every time I went to re-install the MVFuse, the ring slipped off, so I used a tiny amount of silicone caulk to tack it in place and was able to reinstall it. I do plan to replace the O-ring when I can source a replacement.

I thought this might fix my problem, but the same thing occurred again. I pulled out the MVFuse afterward and the pin had dropped again.

One thing that happens is that during prime the MVFuse emits a strong air suction noise and there is a lot of gurgling/bubbling/frothing that occurs.

At this point I'm looking for any suggestions on the best way to troubleshoot this further - am I on the right track, or is the MVFuse a red herring?

I'll attach a series of photos below, and a video if the site will let me. If I haven't given enough information please let me know!

Thanks!
 
Last edited:
Photos of the equipment
 

Attachments

  • Valves.png
    Valves.png
    20.7 KB · Views: 4
  • IMG_9145.jpg
    IMG_9145.jpg
    256 KB · Views: 4
  • IMG_9147.jpg
    IMG_9147.jpg
    596.7 KB · Views: 3
  • IMG_9151.jpg
    IMG_9151.jpg
    736.1 KB · Views: 3
  • IMG_9152.jpg
    IMG_9152.jpg
    617.3 KB · Views: 3
  • IMG_9154.jpg
    IMG_9154.jpg
    602.6 KB · Views: 4
  • IMG_9153.jpeg
    IMG_9153.jpeg
    598.5 KB · Views: 2