New Multiport Valve, Laterals/Standpipe, Changed Sand, Pump running, but will not move water


New member
Nov 26, 2019
Rock Hill, SC
I'm really stuck and am hoping someone can help.
Background Story:
A few weeks ago, I noticed that a large amount of sand was coming out of the returns into my pool. I assumed it had to be the laterals, so I took apart the sand filter and inspected the laterals and stand pipe. That was not the issue, but I replaced it anyway (15 year old system). I found that the multiport valve was bad, so I replaced that. With the new laterals/standpipe, multiport valve and new sand installed, I tried to start the system back up today and the pump will run, but no water moves through the system at all. I have tried backwash, waste, and even filter, but nothing works. I let it run for a very long time until the pump started to get hot - at least 20 minutes.
There are only two things that I can come up with that could be causing this:
1. After being out of commission for a few weeks, the pool is now a swamp. Could that have something to do with it?
2. When reinstalling the new laterals/standpipe, sand, and filter, I did not fill the filter completely with water (maybe 80-90% full). Should I have filled it completely?
My pool details are in my signature. Does anyone have any thoughts? I am at my wits end and am about to overpay to have the local pool guy to come out.


Gold Supporter
May 20, 2020
Katy TX
Pool Size
Liquid Chlorine
My first thought is the multi-port valve. Did it get replumbed correctly? Is the valve in proper position?
You state your pump is overheating - it sounds as it is pushing against a closed valve of some sort, but is there proper suction to the pump?
You tried to move the multi-port valve to a different position without any success. Do you know if you move the handle on the MPV that it is actually turning the valve in it? Did you happen to check that before you plumbed it back in? Could another valve be closed that you may have done to isolate while you made other repairs?

Have you vented your filter to remove the air that was left in it? It is best to leave that vent open when you turn on pump initially.
Filling it to only 80% should be OK so long as you leave the vent open when you turn on pump to let if fill 100%.
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