DE Filter creates geiser thru skimmer when turned off q's

[rio002]

Hi there, new to owning a DE filter but learning as I go. The filter itself is a Spartan (company no longer exists) with Hayward controls so it's an old one. Problem is, when it's run for a couple hours it starts acting like it needs to be backwashed ie: low return pressure, sounds like it's trying to refill the tank etc. but when I shut it off it will belch out the return jet and send a 5-6ft tall geiser out the skimmer, it seems to empty the whole filter tank as I have to then wait for it to refill before it will backwash and rinse. The pressure prior to shutting it off is between 20 and 25psi. I have a 10,000 gallon above ground pool, so it has about 3 lbs. of fresh DE in it and a new seal around the tank. Now if I go right back out within an hour or so and shut it off to backwash and rinse again I don't get the geiser just a small belch out of the skimmer. A few weeks ago it ran fairly normal at 15-20psi and only did this when I knew the DE was low--but right now there is plenty of DE in it and it's still doing this. Any advice will be greatly appreciated. Thanks!

[Poconos]

Sounds like the filter tank has a lot of trapped air that is under pressure. A large volume of pressurized air will cause the geyser effect. Filters should eventually purge themselves of air by some mechanism. Not familiar with DE filters but is there an air relief valve or anything that might resemble one on the top somewhere? If you find something try opening it a little while the pump is running until water comes out. Best guess for now.
Al

[rio002]

There is an air release valve at the top, and I open it when the tank is refilling to let the air out but I'll try opening it before shutting it off and see if that helps. LOL the last geiser sent my skimmer basket flying into the air and it landed dead center of the pool, that was fun to find as the pool isn't cleared up yet :)

[rio002]

Alright I was just outthere, and opened the valve for a minute before shutting it off, but it still did the geiser thing. Still wondering what's causing it.??:confused:

[JohnT]

Somewhere you most likely have air trapped. Any capped off returns or cleaner ports? Solar heating or other heater that hasn't been bled? Long pieces of flexible hose connecting your filter to the returns?

[rio002]

I checked all connections, no leaks, none capped off, all hoses are less than 4ft long except the backwash hose of course. No heater or solar accessories. But it seems to be building up the air up from somewhere over time, just can't find where. :)

[Poconos]

Something is wrong. If you opened the air release for a minute, that sounds like a long time. Did water finally come out? You need to leave it open until that happens. My guess is it has to be the filter bacause if there was trapped air after it, like in an unused return line or something, it (compressed air) would have to move the mass of water in the filter back through the pump and skimmer and I can't imagine getting that much of a blast from the skimmer. A thought, have someone hold their hand over a return jet as you kill the pump and see if you continue to get a flow for a couple seconds after the pump is shut off. Just another data point. Other than these comments, I'm out of ideas for now.
Al

[PatL34]

Something is wrong. If you opened the air release for a minute, that sounds like a long time. Did water finally come out? You need to leave it open until that happens. My guess is it has to be the filter bacause if there was trapped air after it, like in an unused return line or something, it (compressed air) would have to move the mass of water in the filter back through the pump and skimmer and I can't imagine getting that much of a blast from the skimmer. A thought, have someone hold their hand over a return jet as you kill the pump and see if you continue to get a flow for a couple seconds after the pump is shut off. Just another data point. Other than these comments, I'm out of ideas for now.
Al

Seems to me what is not working is the check valve, or lack of it. A check valve should be installed immediately after the pump, and will prevent your "gieser' very quickly.

This could be bad workmanship on the part of the original installer.

Hope this helps.

Pat

[Poconos]

There should be no need for a check valve in a normal system. Granted it would probably solve this specific problem, but there is some issue that is not yet explained.
Al

[rio002]

OK I went back through and tightened all my hose clamps (was surprised I got a 1/2 turn or so out of the ones on the filter-these were tight 3 weeks ago). I let the filter run all day, it was at 25psi tonight, I opened the air valve and let it stay open for about a minute- the whole time water was coming out with some air too. I left it open til my psi dropped to 20, then simultaneously shut off the pump and pushed the control handle down so it was in between gears--this caused only a small belch out of the skimmer, backwash hose and return valve. It sounded like I got a belch from under the control handle though- is that normal when it's in between gears?
Oh, and the return valve does continue to push after the pump is off for about 10 seconds. I really appreciate all your help in tracking this down, I've only had sand filters before, but those only survive so long lol.:D

[JohnT]

I opened the air valve and let it stay open for about a minute- the whole time water was coming out with some air too.

As long as air is coming out at all, I'd leave the bleed valve open. Only shut it when it's all water.

[Poconos]

Another thought...are you seeing air bubbles in the pump basket after the pump has been running for a while? 15 minutes or so. I wonder if you're sucking air from someplace and therefore can't bleed the filter or when you do it just gets trapped air again. Anything in the line between the pump and filter other than a hose or pipe? Also, I wouldn't change the valve setting while under pressure. You said it has Hayward controls and I assume that means a multi-port valve. The danger you run is when you release pressure with the handle the rush of water and/or air can lift the spider gasket off its seat and you'll probably destroy it. The burp out the waste line and all the other things still point to trapped air in the filter. Again, best I can do for now.
Al

[rio002]

Yes after it runs about 2 hours or so, the skimmer seems to have less suction, sometimes it even releases the basket like it burped while running-but if I put my hand down the skimmer the suction feels pretty strong. But yes after running for that long the "whirlwind" of water in the skimmer just sits still and all the stuff on top of the water just passes right by the skimmer, because of the Algaecide I use it becomes a thick foam in there.

Good to know about the spider gasket deal--I'll quit shutting it off like that lol :o

It is multi-port valve but there's nothing but a hose in between the filter and pump, in fact all connections between the pool, filter and pump are just straight hose.

Traci

[MarkC]

Can you check your hoses before the pump for any small slits or holes. If you had a small hole in the suction side you would not see any water leaking but would be letting air enter your pump which then would end up in the filter housing.

[PatL34]

From what I have been reading from all these threads, I keep thinking that the problem seems to be with the multiport valve.

If it is the type that you pull up and push down for backwashing, one of the seals may be worn out.

With the Hayward Multiport type, the seal between the casing and the top may be leaking, allowing air to be drawn in.

Just my thoughts.

(Poconos. I still like to see a check valve downstream of the pump. It protects the pump seal and the motor. Standard engineering practice.)

Pat

[rio002]

I checked all hoses, no slits or holes to be found and made sure all clamps were in the right places and tight. I did find one pvc connection that goes from the pump to the filter/multivalve control that looks tight, but actually has some play in the threads, tightened it up and will check tomorrow morning. I did notice my psi was sitting between 15 and 20 (when it's this low it doesn't do the geiser thing, provided I open the air valve long enough) today so perhaps I have had several small air leaks that are slowly being taken care of by retightening all the clamps yesterday and the pvc connection this evening? I'll let you know in a.m. :)

[Poconos]

Pat, the only objection I have to check valves is the additional restriction they present to the system just because of their structure and turbulence they generate. Of course you could go grossly oversize on the valve but then the cost goes way up and I'm a cheap guy. But, when you consider the investment in equipment and the pool, one shouldn't care about another $20 or so. Also, your comment about the multi-port valve, this is on the pressure side of the pump. Air wouldn't come in, water would be blown out. Air leaks have to be on the suction side.
Al

[rio002]

Well three knuckles a bleedin' later, took off the hoses and pvc fittings that lead from the pump and return jet to the side of the multiport valve. The one from the pump did have a small leak that I hadn't seen because it was dripping into a bucket containing extra de--which never looked wet until you touched it, apparently whoever originally did this--had issues about plumbers tape, all of it was ran backwards (so when the pieces were threaded back on all the tape was bunched up and not in most of the threads) fixed that and the leak. Let it run for 4 hours. Now it's to the point where if I open the air valve all the way for 15 seconds, (timed it) the air is fully out, psi reads 10-15 and I can shut it off without even a belch through the skimmer or anywhere else. Now if this sounds like normal procedure for one of these, then you guys were right about it sucking air through very small places and we have it fixed--if it doesn't sound right then please let me know, like I said this is my first de filter, so I am depending on the experience here--which let me tell you has been excellent so far.:D

[rio002]

AAAHAAAA! I think lol.........ok I shut it off tonight the same way I mentioned before (after letting the air valve open til it ran just water) after I shut it off I closed the air valve and for several seconds (about 15 or so) I could still hear and feel air coming out of the air valve that was closed. :eek: So technically couldn't this be where it's sucking the air in from?
It bugged me all day that while I can get the geiser to stop by using the air valve prior to shutting it off, doesn't it reason that I am merely treating the symptom?
I tried tightening the air valve (just by hand) to see if I could get it to stop, but it just kept pushing air out, not a huge amount, but in my mind I would think that over several hours of running that it could suck in enough air to cause my geiser problem. Does this sound on track?