New DE filter installed worked fine till first backwash now it has 0 psi pumppressure

Hey im looking for some guidence on a new self installed Hayward DE4820 48sqft, 96GPM, 363LPM which takes 6 lbs of DE per backwash. I have it mated to a 1hp hayward super pump. First time I turned it on and added DE pump pressure was 8 psi after vacuuming algae off bottom pump pressure slightly exceeded operating norm as per manual I backflushed till water turned clear then rinsed as recommended with hayward control valve for 20 seconds. Switched control valve back to filter and added DE 6 lbs. I bled air out of the top air pressure releaf valve till water came out as recommended however water pressure never left 0 and the pump filter basket has air in it. Usually this means I have leaves or dog hair in the strainer or pump strainer which I checked clean. My question is what process did I do wrong? Water pressure is moving but very low filter is still cleaning. Should I backflush again? I have no leaks in plumbing.

Welcome to the forum.
I don't know much about DE filters but it sounds like you didn't do anything wrong. When you added the 6# of DE did you mix it with water in a bucket first to make a slurry then pour it slowly into the skimmer? Since the skimmer and pump baskets are clean and you do have reduced flow my next guess would be a gunked up impeller. You mentioned doghair so I also assume you have to deal with a hair issue before. This stuff could easily get tangled in the impeller. Kill power to make sure the pump cannot come on accidentally, remove the pump basket and reach in the hole to the pump. If you feel hairs or stuff in there you can use a stiff hooked wire to clean it out. Since your pressure is zero that rules out a problem on the pressure side so we look to the suction side. If the suction line from the skimmer is clear, baskets are clear, no air leaks, then the only thing left is that impeller. Let's see what you find.
Hope this helps.
Al

I’d guess maybe you didn’t let the pump run long enough.
When I recharge my DE filter it sometimes takes several minutes for the system to get back. During the loading phase the pressure reads zero. A lot of air comes out of the jets and eventually all is well.
Sometimes though it never comes back and I have to prime the pump. Even then it takes a few minutes to stabilize.

Welcome to the Forum!

Please look at this thread for using your DE filter.

Check to see if teh skimmer weir (door) didn't get stuck in the up position. Also check to see that you didn't backwash so much water out of the pool that the skimmer is sucking air.

I read the DE filter FAQ, which pretty much covered everything I already did except about the bleeding of the air prior to adding DE on the filter to allow DE to stick to the grids. I did this but my problem still exists. Im wondering if air can go from the filter to the pump strainer?

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Originally Posted by Poconos

Welcome to the forum.
I don't know much about DE filters but it sounds like you didn't do anything wrong. When you added the 6# of DE did you mix it with water in a bucket first to make a slurry then pour it slowly into the skimmer? Since the skimmer and pump baskets are clean and you do have reduced flow my next guess would be a gunked up impeller. You mentioned doghair so I also assume you have to deal with a hair issue before. This stuff could easily get tangled in the impeller. Kill power to make sure the pump cannot come on accidentally, remove the pump basket and reach in the hole to the pump. If you feel hairs or stuff in there you can use a stiff hooked wire to clean it out. Since your pressure is zero that rules out a problem on the pressure side so we look to the suction side. If the suction line from the skimmer is clear, baskets are clear, no air leaks, then the only thing left is that impeller. Let's see what you find.
Hope this helps.
Al

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Poconos you were 100% right whoa. Argh! I removed the plumbing from the pool to the strainer to reinstall with new PVC. Just because you mentioned it I checked the input hole to the pump impeller VIOLA! It was gunked up with dog hair bamboo shoots and DE. I removed the 6 bolts on the Hayward super II pump and cleaned all inlets how you can do that without removing it I donno as the inlets move diagonally and I did use a wire hanger. The 6 bolts are nothing to remove and you get everything clean that way. Anyway glued up the PVC fixed the pump back to the strainer. Followed the bleeding the air before the DE input advice then I noticed jacuzzi output on my pool jets from zero psi to 20 in one fix. Now things circulate the pool in less than a minute crazy wave action. My water turnover is very fast now. I probably would never have checked the impellers although I did this once before about 8 years ago. I just would not have thought of it but you were right so thanks for saving my sanity. If you have zero pump pressure CHECK THE PUMP IMPELLER before checking the plumbing. After you check the obvious baskets. Next step for me was to break down the brand new hayward pro filter to clean the grids and I wasnt looking forward to that just yet. WEEEE thanks again!

Air can't pass backwards through the system against the flow of water. Check the seal on the pump lid. I assume you have air in the pump while it's running, if it's not the seal, there is a leak in the plumbing and we'll help you trace it down.