UPDATE-GUESS WHAT WE FOUND. Filter draining during the night

[rmklaw]

I am troubleshooting a problem that ocurred after I replaced the filter, heater and had to replumb. I have solar. When the solar 3-way valve turns of for the night, it looks like in addition to the solar panels draining as they should, my filter is draining back into the pool overnight. In working with the Autopilot people, they think that with my current plumbing (see the second picture here post290428.html), not only are the solar panels draining but also the filter is draining, which would make it hard to prime, and when the solar valve opens there is too much air in the system.

If you look at the second picture, the output of the filter goes to the check valve and from there goes to the 3-way valve. When the solar 3-way valve closes at night, the panels drain (as they should), but because of the 3-way, allowing draining the panels, the water from the check valve empties, no longer offering resistance to stop the water from the filter to drain.

They are suggesting that the output of the check valve to the 3-way solar valve should go up so that the 3-way solar valve is much higher than the check valve leaving the check valve with water in it to keep the flapper close through water pressure instead of allowing slow air leaks. Right now the multiport valve (filter) is level with the checkvalve and the 3-way valve, and with the solar side closed there is nothing to stop the filter from draining through the return. I can watch the check valve emptying. The path goes from the open side of the 3-way to the Mastertemp heater and out to the returns. Does this make sense? Thanks.


Here is the picture (second one) post290428.html

 

[Bama Rambler]

Re: HELP - Filter draining during the night

That picture's a little close to tell exactly what's going on. Can you back off a bit and take another pic?

Sounds like either the check valve is leaking or the solar valve isn't closing completely.

 

[rmklaw]

Re: HELP - Filter draining during the night

What I am being told is that for the check valve to stay completly closed, it needs some backpressure from water in the checkvalve housing. From the plumbing configuration and the plumbing being low, when the solar drains, the check valve housing also empties.

The Pool Pilot engineer said that the 3-way valve should be higher than the check valve so water always remains inside the check valve housing to prevent sipage.

 

[Bama Rambler]

Re: HELP - Filter draining during the night

Not knowing what brand of valve that is, the Jandy check valves have a spring to keep the flapper closed even if there's no back pressure.

 

[rmklaw]

Re: HELP - Filter draining during the night

It is a 3-way Jandy. According to Pentair and Pool Pilot, even with the spring, if the check valve has no water to exert some additional pressure, it is not totally airtight and air will get in. Water pressure helps keeping it shut (according to them). Their suggestion is to raise the 3-way valve connected to the output of the check valve about a foot. That would keep the water level in the filter at the same level of the Jandy 3-way valve (two colums of water equalize). That is their reazoning as to why the filter is draining out to the 3-way valve level. Does it make sense? Do I need to worry about heights of valves, etc?

 

[Bama Rambler]

Re: HELP - Filter draining during the night

How long does it take it to drain down?
If it's fairly quick I'd suspect a leaking seat in the valve. Even if it would tend to leak a little as soon as the filter started draining it would pull the seat tighter due to the vacuum created. You may want to check the sealing surfaces of the check valve.

 

[rmklaw]

Re: HELP - Filter draining during the night

Actually, if you look at the picture, you will see that the plumbing from the filter output goes to the check valve, from the check valve to the 3-way. When the 3-way is in the non-solar position, the filter output has unrestricted flow path to the pool return, so what Pentair is saying is that the filter water level will find its level which will be the hight of the filter multiport valve (same hight of the check valve and 3-way). Nothing in the path restricts the water flow when the pump goes off. That is why they are suggesting to change the plumbing so that the 3-way is much higher than the check valve (ideally at filter top height level).

I am asking for suggestions because this is a drastic change requiring major replumbing. Thanks.

 

[mas985]

Re: HELP - Filter draining during the night

It may be true that the check valve would seal better with water than air but you should still be able to make it seal even with air on one side. My check valve is at the same level as the rest of the piping but because it is above water level as is my whole pad, air still fills the pipe after solar drains. It would be difficult to prevent this from happing unless you had trap in the line to prevent water from draining. However, even though there is air on one side of the check valve, the check valve still remains sealed.

Also, technically, the higher the valve the greater the pressure difference on each side of the valve so it should actually seal better at the higher position.

I would remove the flapper, clean it, clean the orifice where it seals in the valve and then lube both with a little pool lube. This will help with the seal.

But from your other post, did you rule out a suction side leak? Last you posted, the pump showed air in the basket when running which is an indication of a suction side leak and if large enough, would eventually drain the filter when the pump is off. Is the pump basket nearly empty in the morning as well?

 

[rmklaw]

Re: HELP - Filter draining during the night

Thank you for your help and suggestions. No suction side issues. The basket is full at startup. The concern is only why when the solar drains, the filter also drains 1/2 way. That is a lot of air to push out. I gather you do not think that placing the 3-way higher than the checkvalve would solve the issue?

 

[mas985]

Re: HELP - Filter draining during the night

Before you do any plumbing changes, I would try cleaning and lubing the flapper first.

Also, there are many parts on a filter that can leak air into the filter such as the air bleeder valve and the backwash valve spider gasket.

To add insult to injury, I just noticed in your posted pictures the location of your flow meter. I wouldn't trust a reading from a meter that close to the fittings. You should have 20" straight pipe on the supply side and 8" on the trailing side.

 

[rmklaw]

Re: UPDATE-GUESS WHAT WE FOUND. Filter draining during the n

You would not believe this one. We found that the dealer delivered the wrong High Flow valve with the Quad 100. It should have been 261050 Triton Quad DE, but instead the installed valve was 261142 DE. In other words, the filter was running backwards. I took the filter apart and the inside of the cartridges were half full with DE and the rest of the inside dirty. The bands holding the cartridge pleats had stretched and were loose. Pentair said that the cartridges were no longer any good.

The dealer made good. Gave me a new high flow valve, check valve and 3-way valve and tomorrow they are giving me 4 new cartridges. I spent all day re-plumbing since the valve and ports are completly reversed from the old one. Tomorrow I will test the system and report.

 

[Bama Rambler]

Re: UPDATE-GUESS WHAT WE FOUND. Filter draining during the n

Glad you found it but bummer that it was what it was.