Pump leaking from bottom when pressure goes up

Jun 9, 2013
63
NC
So I bought a used pool w/ used filter (details in signature line). I just hooked it all up and got the pump running recently. There were no leaks at first. I just put a new hayward pressure gauge on the filter, and determined that the normal operating pressure is about 15 psi. I have a couple of questions....

I added some D.E. powder to the filter, as outlined on this website (I had algae that I was clearing up). The D.E. is really helping clear up the cloudiness. it also makes the pressure go up fast, which is a good thing right now since it means the filter is working good and catching stuff. So a couple of questions:

1. The pressure went up from 15 to 20 psi pretty fast after adding the DE - 2 hours. At that point the return went from pushing a ton of water out at 15psi (real hard flow), to pushing not much at all out (real slow flow) at 20psi. So i went ahead and backwashed and got it back down to 15 again, b/c I was afraid the pump would burn up. I would say it was probably a 80-90% reduction in flow rate. I've always read to let it get up to 10psi past the normal pressure before you need to backwash. But if I were to do that, I would guess there would be almost no flow at all! Is this normal??
2. When the pressure was at 20 psi, the pump was leaking out the bottom. There was a continuous drip about every second. What could this be from? I know it wasnt leaking starting out, and the leaking stopped after I backwashed, so its only happening when the pressure is higher. Makes sense to me but I'm guessing this should not be happening. Are there some type of seals that might be going bad?

(edited to fix typo where i said pump was leaking at 15 psi - it was 20...not 15)
 
1. The 10psi rise is an old and illogical recommendation. We recommend backwashing when the pressure rises 20-25% of the clean pressure. If you are staring at 15psi, you should backwash around 18psi or so ... otherwise the flow rate drops too much as you saw. BTW, the pump will not burn up as long as there is some water movement.

2. Some seal is leaking, but need more info on where the drip is to help figure out which one. Could be the shaft seal or one of the internal o-rings. There are things called "go-kits" that include all the seals for around $20 I think.
 
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