My Pool Sand Filter Has Low Pressure..Low Psi & Multiport Valve Is Leaking..

by Sherry

I have a Hayward S166 Sand filter that has no PSI's in any setting except recirculate. There is water leaking from the backwash valve and I am getting a ton of sand in the pool. I have replaced the liner, the multi valve top piece, O-rings and none of which worked.

I have check the laterals (but not closely) and they all looked fine. My normal pool company has no idea why I have the problems I have and the season hasn't even begun yet.

Thanks for the question Sherry

I know you want to get your pool up and running so I'll attempt to be as helpful as I can. First I would check the PSI gauge. It might be bad. Sometimes just one piece of sand can clog it up. I've had that happen to the sand filters at the YMCA pool several times.

Concerning your leak in the multiport valve, there are a few O-rings and washers that you can check. If you talk to your pool guy, he should know what they are.

These are from top to bottom.

Multiport washer. This goes underneath the handle.

Dial valve O-ring. This goes under the multiport valve cover.

Valve washers.

O-ring for the cover. This sits on the valve body assembly and the multiport valve and gasket assembly.

The tank O-ring/Flange valve.

Be sure you tighten the bolts cross-way. If you just go around the valve cover won't be flat and seat correctly. Laterals don't have to
be broken to not work. They can become impacted with sand. If this happens the water will have no place to go but out. Water will always find the path of least resistance.

If you check the laterals and they're not broken, chances are they might be clogged up.
Be careful to not bang them on the ground. This will cause them to break. You can unscrew them and gently dig out the sand with a stick, then rinse them with a hose to loosen up any left over sand.

Check the sand for channeling. This is when the sand becomes clogged with oil and debris. Feel around the inside sides of the filter for holes, pits, etc...If there are any, you have channeling. Email back and I can give you a good way to degrease the sand filter.

Be sure you have the correct amount of sand in the filter. You can check with the filter manufacturer for the correct number of pounds you need. Also check what is called "freeboard". This is the measurement in inches from the top of the sand to the top of the filter. The sand filter manufacturer should know this as well.

When you put new sand in there's going to be settling and a loss of sand through the returns. You may need to top it off after this happens, but it's very easy when you know the freeboard. Hope this helps and let me know how it turns out for you.


Click here to read or post comments

Return to Pool Sand Filter Problems .

Swimming Pool Water in Sight Glass..Problems..

by Fay
(Central NY)

Should the sight glass be full of water during normal filtering operation?

Thanks for your question Fay

The site glass for swimming pool filters is a convenient way for pool owners to know when the pool water is clear during backwash periods.

It's much better than counting the minutes because it's not the time, but when the pool water runs clear after backwashing.

Visible water running through the pool site glass shouldn't be of any concern.

Happy swimming and have a great Summer


Click here to post comments

Return to Pool Sand Filter Problems .

Closed Valve Setting Still Lets Water Through!...Pool Leaking..

by Denise
(Hamilton, ON)

When I turn my pump to off and my filter valve to closed, water is still entering the pump and I am losing sometimes inches of water overnight!

What is broken and how can I fix it?

Thanks for your question Denise

Anytime you do troubleshooting, you'll want to first look for the obvious. Many times a leak from the valve is as simple as a bad gasket or O-ring that needs to be replaced to stop a leak.

If you're uncomfortable in checking for gaskets or O-rings in the valve, the best thing to do is to call a professional pool tech to come out and take a look at it. Check the pump motor, basket, and impeller for any blockage. Be sure the skimmer(s) and bottom drain are free from debris. You want the water going through the system and have good circulation.

I've written about pools losing water in the links below. There's good info. and some good techniques you can use to see the possible reasons for the leak, where it's coming from, and what to do about it:

Above Ground Swimming Pool Losing Water


Your pool has two main lines; the suction lines and the return lines. The links above mention them and how to know which side the leak is coming from.

Hope this helps and have a great Summer


Donation To My Pool Guy

Click here to read or post comments

Return to Pool Sand Filter Problems .

eBooks Are Perfect Desktop & Mobile Device!!

swimming pool care, basic pool care, above ground pool maintenance, inground, salt water

Click Here To Learn How This eBook Can Save You TONS Of Time & Money


Click Here To Learn The Best Way To Clear Up Your Pool 


All Resources In One Convenient Package. Click HERE To Get Started.

Recent Articles

  1. How To Clear Up A Cloudy Pool eBook

    How To Clear Up A Cloudy Pool eBook

    Read More

  2. Pool Float & Sweep

    How do I keep the hose from my pool sweep and the floater from colliding? If I tie the float off where is the best place, and one last if the float is tied off.

    Read More

  3. The calcium hydochlorite will not dissolve in our pool

    The calcium hydochlorite will not dissolve in our pool. It is suspended in the water

    Read More