Rebuilding Manifold Question - 1 yr old pool

[bigdave]

After building my inground 30k gal pool last spring, I have noticed the cheap valves that came with the kit are already failing. In the fall I purchased Pentair 1.5" PVC, 2-Way Lube-Free Diverter Valves to replace the cheap ones.

I have noticed that once the pump stops, and after a little while, the chamber empties. So everytime the pump goes into it's cycles (usually 2 times a day for 4-6hrs) that it is empty. This can not be good on the pump.

Not sure why this is happening, maybe the pool is sucking the water back toward the pool.

I'm wondering if I should put a check valve right before the pump to stop this?? Has anyone done that?

Am I hiding another problem that may be in the system?

 

[JohnT]

You have an air leak someplace. Check the pump basket lid and the drain plug in the pump basket first. Lube the O-rings and make sure all is tight.

 

[bigdave]

I have checked out the pump with no visual signs of air leaks.

Could it be an air leak in the sand filter causing this? Or Heater?

Unfortunetly the only pressure test I did when I built the pool was cycling the water through the lines to look for water leaks prior to backfilling.

Hope it's not the underground lines.......They are burried under cement....starting to worry again......

My water loss is pretty normal though....

 

[mas985]

An air leak in the heater or filter will usually show up when the pump is on; water will squirt out. It is more likely that a valve on the suction side is leaking. Do you have any air at all in the pump basket when the pump is on?

 

[JohnT]

Water loss won't normally be a problem on the suction side since the water isn't under pressure.

Shut the pump off and listen, and you may be able to hear the air going into the system. Should be around the basket or valves from skimmer(s) or drain(s). Sometimes a little water will also spurt out of a suction-side leak right as the pump shuts off.

The filter and heater are on the pressure side, so a leak there would result in water coming out while the pump was on.

Has the pool always done this, or did it just start?

 

[bigdave]

Do you have any air at all in the pump basket when the pump is on?

Usually just a bubble or two swirling at the top cover.

Has the pool always done this, or did it just start?

Yes, since building it last year. The valves are cheap and it wouldn't suprise me if they are the ones leaking the air. I am replacing them this weekend. But wanted to know if I needed a check valve to address this issue. I didn't want to have to cut into the manifold again after I replace the valves to add a check valve later.

 

[JohnT]

A check valve would just be hiding the problem. In some cases one is needed, especially if the pump is higher than the pool deck by a decent amount. The bubbles in the basket shouldn't be there.

 

[bigdave]

OK, I will skip the check valve. But have another question. No directions with my new valves.

Which way do I point the new valves? They are Pentair 1.5" PVC, 2-Way Lube-Free Diverter Valves.

When closed should the ball or diverted be on the bottom toward the pool? Or spin them around and have the close end toward the pump.

Only problem I see is with the close on top the valve will always be full of water. While if I put the close on bottom it blocks water from the suction pipe.

 

[mas985]

I don't think it would matter too much which way you put them in but valves will tend to seal better when the pressure inside the valve is higher than the off pipe.

So for vacuum side, you want the closed position to be closer to the pump and for the return side, it should be away from the pump.

Ball valve orientation shouldn'tt matter at all.