baffled - low flow

[rickpx14]

Hi! Happy to find this forum. I am new here and I've searched this forum and have found all sorts of good advice but unfortunately have so far had no success. Here's the problem: My pump turns on fine. It seemingly builds up pressure pretty good but is only sucking a little bit of water through. (I say the pressure seems fine because when I remove the basket lid, you can hear the pressure relieve - and it instantly sucks up the water sitting in the basket.) I'll run the pump for a while and only a little water comes through (I am going to waste here, so it must not be a filter problem-right?) When I turn off the pump, water swooshes back into the basket from the pressure side. (Could it be a blockage on down the line? that doesn't seem right since it would have to go through the strainer etc) Here is what I have done: I repiped all suction side piping, taped, lubed etc. I can't believe that theres any air coming in there. I dont have a snake but I did have a TV cable I could twist and turn to get through the underground pipe (from the skimmer to the pump) and it went through no problem. I even put some drain opener down there. *At one point while running the pump I heard a thump which sounded a lot like a clog moving from one position to another, but after opening all pipes leading to the pump, I found no clog. Bizarre. So then I thought maybe its the impeller on the pump. Well, I had that aprt and it is clean. I took member name WASTE's advice and reached in to the back of the pump with my 7/16 and turned it back and forth (was able to do so) but that didn't have any effect. Other details: the pressure gauge isn't moving - just sits at 5psi. I was vacuuming fine before the problem started. Then at one point after that the pump was 'surging' (psi would go up and down from 5 to 12 psi). Sorry for all the detail but I figured if I was going to get any help you should have as much detail as possible. Any ideas?

[PatL34]

Difficult to get an idea as to what is happening here. Have to ask some questions.

1. Have you opened up the multiport valve to the filter to check for any blockage or problems there.

2. The surging you mentioned could be a problem with not having enough water in the pool, and the skimmer having a vortex in it sucking air.

Hope this helps.

Pat

[rickpx14]

Thanks for the reply. Yes, I have checked the multiport valve and there doesn't seem to be any problems there. I have it set to waste so that the (sand) filter is taken out of the equation. And there is plenty of water in the pool...it has all the signs of an air leak but I've repiped everything and don't see any water leakage or hear any air leakage when I shut off the pump. I'm really stumped. thx..

[PatL34]

If you are getting air into the filter, i.e. you have to open the vent valve on top, then you have a suction- side leak.

Check the O-ring to the pump basket has Magic Lube, or similar.

Check with a 3 - 4' piece of PVC pipe held against one ear, the other at different places on the suction piping. When you hear bubbles, that's where the leak is.

Hope this helps.

Pat

[rickpx14]

thx Pat. I went out and opened the top valve on the filter and air did escape. Even though I am going to waste, does this mean that there is def. an air leak problem on the suction side? Should I leave this open when going to waste? closed? does it matter? sorry - i'm trying everything here. I have already checked the oring around the basket (several times) and it seems ok. And I don't hear anything on the suction side as far as leaking or bubbles when I turn the pump off. ...and the reading on the presure gauge just sits at 4-5 psi -does this mean anything? thanks again...

[PatL34]

You need to set the multiflow valve to go through the filter to check for air infiltration, when the pump has been running a good 1/2 hour. If you get a lot of air from the filter vent, i.e. more than a couple of seconds, then you have an air leak, and check as before with the pump running.

If not then you need to check the pressure side of the pump to the filter. Also you may need a new gauge. Remove it, and if there is pressure from the connection, and the gauge drops back to zero, then the gauge is alright.

You mention a back flow when the pump is shut off. Are there any valves downstream of the filter that might be closed or restricted? That could account for the back flow as the filter depressurerizes back through the pump. This also could account for an air-leak on the suction side, as this air pressure is driving the flow back from the filter.

Hope this helps some more.

Pat.