Help diagnose DE coming from main drain with pump off

[Surf Hawk]

I recently noticed DE has been coming out of my main drain when the pump shuts off. I searched and found some good threads here that it is probably an air leak somewhere in my system, allowing water/DE to drain out of the filter and back into the pool. What I can't figure out is where the leak is. I have a Hayward 4820 filter with a Variflow and solar water system sometimes on. Some tests and observations I did based on those threads:

1) With pump running, loosen the air valve on top of filter. Air hisses out for a few seconds, and then water.

2) Shut pump down, and I hear a gurgling noise from the filter, and start to see cloudiness in the pump lid window. There also seems to be water coming down from my solar system (which has not been turned on for a week).

3) Pour water over connections when pump running, don't see anything funny.

4) Note my check valves, I have one on the outlet side of the filter between the filter and a Jandy valve that bypasses the solar, and another on the solar return. Both are pretty old no-name brand ones that could be the culprit.

5) For the 3 years we have owned this house, when the pump starts up we always get about 10 seconds of bubbles out the returns, a serious purging of air. I have never done anything about it, because the pool has run smooth using the TFP methods.

Thanks for any advice you can give on what to troubleshoot.

 

[jblizzle]

I think I would start with the check valves. Water should not really be able to go up to the solar if they are working.

 

[Surf Hawk]

Good plan. Is there anyway to test without cutting them out and replacing them? It's pretty tight in there, think I will have to replace a lot of piping just to replace those check valves. If I do it, I guess it will be a good time to put more 45s in there instead of 90s.

 

[jblizzle]

Post up pictures of your setup.

 

[Surf Hawk]

I hope I labeled this right and it makes sense.

Check valve #1 is after filter, check valve #2 is solar return. I think.

 

[jblizzle]

Well, those are certainly not the preferred flapper style check valves. I also think the ones you have add a lot more resistance to the flow.

I agree it is going to be a bit of a mess to replace them though.

 

[Surf Hawk]

I think I can replace the Solar check valve pretty easy, the one off the filter will need a couple pipes cut to get access. Thinking the Jandy 1.5-2" check valves.

 

[jblizzle]

yup. Or the 2-2.5" Jandy check valve which is a little bigger.

The first number is the size of the pipe that can slide into the valve. The second number is the size pipe that matches the inlets and uses a coupler to attach.

 

[JoelFitz]

If you have DE around the main drain after the pump shuts off you sir have an air leak causing the filter to backflow to the pool. Water follows the path of least resistance and it's much easier going through the pump than through the filter elements/heater/chiller etc...

Any water on the equipment pad? Maybe under the pump around the seal area? Do you have anything adding air into the system like an ozone generator? Does your pump spit a little from the lid when you shut it off? Should be simple to find, you can get everything primed up good and once everything settles shut the pump off and put your ear to every valve, clamp or connection and listen for air intrusion.

GL!

 

[Surf Hawk]

Hi Joel, there is no water on the equipment pad. I do not have an ozone generator. I have at times seen the pump spit water from the lid, it happens only about 5% of the time, and have not seen it since I've had this problem.

I shut the pump off and then turned the Multiport to CLOSED and I hear a hiss coming from the multiport. It could not find a place where air was getting into the multi-port, that is the sound did not change when I moved my hand around seals. It sounds like it's coming from within the multiport. Could be something there, never pulled one apart, are these the spider gaskets I hear about?

I think based on Jblizzle I'm going to hunt down the check valves, it sounds like water is going up into my solar the wrong way because the check valve is blown, and the VRV lets air into the system when the pump is off? Not sure.

 

[JamesW]

I suspect that the leak is at the waste line. I would disassemble, clean and lubricate the multiport valve and stem orings. I would replace the spider gasket if it's bad. I would also put a check valve between the pump and filter.

 

[Surf Hawk]

OK I have a check valve on order to replace the one to the solar as it sounds like water is coming down from there when I shut the pump off.

I also opened up the multiport and didn't see much that was worn. I cleaned a bit and re-lubed the spider gasket and the o-ring that seals the two halves. I don't know what the stem o-rings are, is there a good guide on servicing these multiport valves? I don't mind ordering a new kit to replace the spider gasket and o-ring just to be sure.

If it's not the first check valve or a multi-port leak, I replace the check valve between the pump and filter.

Thanks for the help.

 

[Surf Hawk]

Took check valve out to solar and capped it. Problem still there.

Realized the other check valve was not between filter and pump, but was between filter and return to pool. Put new Jandy check valve between filter and pump. Problem solved! No more DE out of drain, no more bubbles coming through returns at system start up. Probably have had this problem since we moved in 3 years ago. The multiport probably still has a leak, but this check valve at least stops it from making the DE go back into pool.

Thanks for the help.

 

[JamesW]

 

[jblizzle]

Glad it worked, but that just means that you do infact have a leak that allows air into the filter when the pump is off. Now the check valve is just not letting the water drain through the pump.

 

[Surf Hawk]

So is the next thing to de-bug the Multiport? Should I replace the seals including the spider gasket? Is should I use a bubble leak detector solution on more seals? Thanks.

 

[JamesW]

I suspect that the leak is probably in the waste line. What can happen is when the pump is on, the water pressure pushes down on the diverter and makes a good seal preventing water from leaking out the waste line.

However, when the pump is off, the pressure in the filter actually becomes negative (vacuum) and pulls up on the diverter and pulls in air.

There is a spring in the multiport that helps hold the diverter down, but the diverter stem can get sticky.

Usually, the issue can be resolved by taking the multiport apart and cleaning and lubricating the parts including the diverter stem oring.