High Filter Pressures??

[les_garten]

I have a Pentair Intelliflow and a Pentair DE Filter.

I needed to clean the filter because of high pressures. I took the filter apart and a number of grids were holed. So I replaced them all. Put in New DE but my pressures did not go down?

All the returns are returning strong flows.

Any ideas about how to go about troubleshooting this?

I have a Pentair 320 Feeder and a Electric Heat Pump heater.

 

[JohnT]

Does your pressure gauge go to zero when you shut the pump off? Does your filter have a multiport valve you can set to recirculate?

What pressure do you normally run at and what is it now?

 

[les_garten]

Does your pressure gauge go to zero when you shut the pump off? Does your filter have a multiport valve you can set to recirculate?

What pressure do you normally run at and what is it now?

Yes it goes to zero.

If I switch to recirculate it is zero and stays at zero.

It should run around 10-12 PSI aqfter a good clean and it was running 25-30+. So I went to clean and found the grids that had some issues.

I replaced all the grids and it is exactly the same as before.

Also the Intelliflow says I need to service soon.

Thanx for the quick reply!

 

[JasonLion]

Are you running the IntelliFlo in one of the constant flow modes? Also, what speed/flow do you have it set to? Finally, did you switch to the IntelliFlo just recently, or has it been working correctly for some time and just started to have problems?

Any blockages on the return side can cause the pressure to go up. That could be an issue with the filter, but could instead be a valve being closed that should be open.

 

[Richard320]

I'd still suspect the gauge. My returns slow down noticeably when it gets time to clean. If your water is circulating well, and you have new grids, it's most likely the gauge, not the filter or plumbing.

 

[les_garten]

Are you running the IntelliFlo in one of the constant flow modes? Also, what speed/flow do you have it set to? Finally, did you switch to the IntelliFlo just recently, or has it been working correctly for some time and just started to have problems?

Any blockages on the return side can cause the pressure to go up. That could be an issue with the filter, but could instead be a valve being closed that should be open.

I have all the valves open presently.

The Gauge is a Wika Oil filled. The reason I think the gauge is OK is because the Intelliflow says I need to clean as well.

I have not changed the intelliflow since initial setup. I have it set in manual right now because the pool needed a little cleaning after being off for a few days and I have some DE that got in the pool somehow.

I normally have it at 60 gpm and do a turnover in like 3-4 hours. 10,000 gallons

Right now in manual it is running pretty fast.

I may pull all the Jandy valves and the multiport apart and see if there is some trash in there.

Reason I think it is not the gauge is because it is a Professional gauge and the Intelliflow is complaining as well.

- - - Updated - - -

I'd still suspect the gauge. My returns slow down noticeably when it gets time to clean. If your water is circulating well, and you have new grids, it's most likely the gauge, not the filter or plumbing.

I would think that as well except this is a good gauge and my Intelliflow is complaining as well.

I have another spider coming for the multi valve. I may have another gauge as well. One of the cheap plastics that come on the valve.

 

[JasonLion]

Right now in manual it is running pretty fast.

The faster you run the IntelliFlo, the higher the filter pressure is expected to be. If it is running faster than it's normal speed then the higher than normal filter pressure is to be expected. What is "normal" for filter pressure totally depends on the speed you are running the IntelliFlo. So if you have been changing the speed the IntelliFlo is set for, it is to be expected that the filter pressure will be different than normal.

Another thing to keep in mind: if several grids had holes, then the filter pressure would be lower than "normal". Holes allow water through without filtering. Fully intact grids will have more resistance to flow and thus cause higher filter pressures than grids with holes. If you got your impression of what "normal" was when the grids were already damaged, the current behavior is to be expected.

Finally, the FNS Plus comes in several sizes, all but the largest size are too small for the IntelliFlo to ever be used at full speed. Or to say that another way, it would be normal for an IntelliFlo at full speed to damage the grids of any but the largest model of FNS Plus. Running the IntelliFlo in constant flow mode, will allow it to ramp up to it's highest speed as the filter gets dirty. If used with one of the smaller FNS Plus filters that would be expected to damage the grids unless you have configured the IntelliFlo with a limited maximum speed.

 

[les_garten]

The faster you run the IntelliFlo, the higher the filter pressure is expected to be. If it is running faster than it's normal speed then the higher than normal filter pressure is to be expected. What is "normal" for filter pressure totally depends on the speed you are running the IntelliFlo. So if you have been changing the speed the IntelliFlo is set for, it is to be expected that the filter pressure will be different than normal.

Another thing to keep in mind: if several grids had holes, then the filter pressure would be lower than "normal". Holes allow water through without filtering. Fully intact grids will have more resistance to flow and thus cause higher filter pressures than grids with holes. If you got your impression of what "normal" was when the grids were already damaged, the current behavior is to be expected.

Finally, the FNS Plus comes in several sizes, all but the largest size are too small for the IntelliFlo to ever be used at full speed. Or to say that another way, it would be normal for an IntelliFlo at full speed to damage the grids of any but the largest model of FNS Plus. Running the IntelliFlo in constant flow mode, will allow it to ramp up to it's highest speed as the filter gets dirty. If used with one of the smaller FNS Plus filters that would be expected to damage the grids unless you have configured the IntelliFlo with a limited maximum speed.

I'll have to see if I am running it too fast on a few settings.

- - - Updated - - -

On another note, could this be resistance from a heater going bad and increasing resistance?

 

[chiefwej]

From what the OP is saying, I think he has a VF pump not a VS. So any restriction that reduces the flow causes the pump to increase its speed in a effort to maintain the set flow rate. It sounds like there is something restricting the flow somewhere.
If that is correct: When you switch to recirculate are you bypassing the filter and does that allow the pump to run slower and maintain flow? If so the restriction is in the filter, if not its elsewhere.

 

[les_garten]

From what the OP is saying, I think he has a VF pump not a VS. So any restriction that reduces the flow causes the pump to increase its speed in a effort to maintain the set flow rate. It sounds like there is something restricting the flow somewhere.
If that is correct: When you switch to recirculate are you bypassing the filter and does that allow the pump to run slower and maintain flow? If so the restriction is in the filter, if not its elsewhere.

When I go into recirculate the filter is bypassed and the gauge reads zero, couldn't really denote a speed difference.

 

[les_garten]

So here's where I am with this problem. I have bought another Filter. It's a Hayward 4820. I had a Pentair 36 DE.

So while doing a partial water change I have been doing a few things.

When I am in filter with a clean filter. I am at 27 PSI. When in Backwash I am at 13 PSI. In Recirc I am at 0 because the pressure gauge is on the filter.

Since I am changing filters, I have to repipe a lot. I am also removing a non functional heater. I am thinking about adding one or two more pressure gauges. Where would you add pressure gauges if you were me?

I am thinking about one after the filter at least. That would help me determine pressure when I am in recirc mode at least.