1hp AGP Hayward won't pump over 14psi

[nbarnard]

Hey guys, recently purchased a 10 year old pool setup and after cleaning sand filter pressure is about 10 PSI, however when it builds to 14 PSI it loses almost all flow (I've been experimenting with DE in the sand filter). Just wondering what that pump should be able to produce in terms of pressure. Haven't checked impeller for damage. No leaks or air in strainer. See below for specs.

thanks,
Nathan

 

[pooldv]

Welcome to TFP!

More pressure on the filter gauge is a sign of less flow through the filter, not more. There will be more flow at lower pressure. We normally recommend backwashing the filter when the pressure rises 20-25% above clean pressure. DE will make it filter better, clog faster and cause pressure to rise.

 

[domct203]

As mentioned, a 25% rise in pressure is the signal to clean the filter.

Adding DE is going to increase pressure as well. How much are you adding?

Pool School - Add DE to a Sand Filter

 

[nbarnard]

Thanks, but shouldn't that pump be able to produce more than 14 psi? Or am I understanding it wrong?

Initially I put in 4 cups of de to see a 1psi raise, then I did 2 cups, now 0 cups and it flows good, probably try 1 cup next. Still why no flow at 14psi?

 

[domct203]

Thanks, but shouldn't that pump be able to produce more than 14 psi? Or am I understanding it wrong?

Initially I put in 4 cups of de to see a 1psi raise, then I did 2 cups, now 0 cups and it flows good, probably try 1 cup next. Still why no flow at 14psi?

Think of it more like a 'backpressure' gauge. As you add restrictions in flow (dirty filter, solar panels, smaller return jets, etc) pressure will begin to build, the gauge shows that pressure. This is why everyone's clean pressure is different as we all have different setups.

The reason that adding DE to your sand filter raises filter pressure is because you are decreasing the size of the openings in the filter media (also catching smaller particles).

 

[Griswald]

Pressure can only come from a restriction to flow. The more restriction, the higher the pressure, up to the pumps limit of course.

The pressure gauge is on the "dirty" side of the filter and raises because the flow through the sand and/or DE and/or cartridge gets blocked by dirt etc.

 

[duraleigh]

Have your family hold their hands over the returns tightly. I think you'll see psi go up.....if not you may need a new gauge.

 

[Kiss4aFrog]

Welcome to TFP nbarnard

 

[nbarnard]

Thanks guys! I understand the cause of higher PSI. My question pertained to the max psi attainable for my pump. I did plug the eyeball and psi went up momentarily to 16psi, but then down to 14 when blocked, and 10psi when released (clean filter). Should I consider getting a new guage or does this sound typical for a 10yr old single speed 1hp agp pump?