High sand filter pressure

[whydidigetapool]

I have some high sand filter pressure issues. I've recently moved to this house which has a pool. I believe when I first saw the gauge on the sand filter three months ago it sat about 70kpa (10psi)

For some reason now it is about 100kpa, photo below shows 110kpa as I added some DE to the skimmer

I have replaced the gauge with a new one. I have done a somewhat deep clean of the sand filter (which didnt appear too dirty). Both the above didn't reduce the pressure.

Water is crystal clear, skimmer and pump baskets clean, no air bubbles in pump lid, use a dolphin/maytronics robot to clean to reduce load on sand filter

I've had to drain approx 2500-3000L of water tonight due to heavy rains in the past couple of days and noticed the pressure sat at 65-70kpa when wasting which makes me think theres an issue with the sand causing the excess buildup of pressure

What should or could I try to do from here to lower the pressure?

 

[woodyp]

70 kpa equals only 10 psi. Why do you think that's high? My sand filter clean pressure is 12 to 14.

 

[Razorhog]

After using google to convert kpa to psi, those numbers are normal. My clean psi is 18 (124kpa) and I backwash at 23-24psi (165kpa)

 

[Richard320]

the pressure sat at 65-70kpa when wasting

Stop right there. On waste, the filter is out of the system. It should show zero pressure. If you show pressure on waste, you probably also show pressure when off, which means a bad gauge. And if it goes to zero off but shows pressure on waste, then you have an internal leak on the multiport.

 

[whydidigetapool]

It's a brand new gauge, both the old one and new gauge one zero when pump turns off. Gauge works

Internal leak meaning rotor/spider gasket is busted?

 

[whydidigetapool]

70 kpa equals only 10 psi. Why do you think that's high? My sand filter clean pressure is 12 to 14.

I'm concerned as its sitting at 14.5-15psi as normal now when I know I saw the gauge sitting about 10psi when I moved in

 

[Richard320]

It's a brand new gauge, both the old one and new gauge one zero when pump turns off. Gauge works

Internal leak meaning rotor/spider gasket is busted?

That would be my guess. Something is interfering with normal operation. You just shouldn't show pressure on waste. Waste is into the multiport and straight out the overflow, bypassing the filter completely. So why does the filter show pressure?

 

[whydidigetapool]

After using google to convert kpa to psi, those numbers are normal. My clean psi is 18 (124kpa) and I backwash at 23-24psi (165kpa)

I'm pretty sure when I backwash it sits about 70-80kpa. So again lower pressure than when filtering

 

[whydidigetapool]

Wo

That would be my guess. Something is interfering with normal operation. You just shouldn't show pressure on waste. Waste is into the multiport and straight out the overflow, bypassing the filter completely. So why does the filter show pressure?

Would there be any residual pressure still since the pump pushing the water somewhere, even if it is to waste? I did a search and cant find anywhere on the net if there should or shouldn't be pressure when wasting water

Also it does leak water out the backwash/waste pipe when it is on the filter function. So theres an issue with the multiport seal either way

 

[mknauss]

Where does your backflush water go? Out a line into the yard? Into the sewer? Unless the waste line is very small, there should be no filter pressure when on backwash/waste.

 

[whydidigetapool]

I put it out to the sewer. I attach a flexible 40mm vinyl/firehose to the waste pipe. It's approx 10m long? Interesting, I get pressure of about 80kpa when back washing too

 

[whydidigetapool]

As an update. Iv installed a new pentair rotor/spider gasket. Not leaking out of the waste pipe anymore. Pressure still high, no change ?

 

[mknauss]

Your signature does not show your pump. An oversized pump for the system can also have high pressure.

 

[whydidigetapool]

It's an onga ppp1500, 1.5hp pump. 50mm piping in, 40mm piping to the sand filter