Low to Zero Pressure in Filter

[donpolo]

I have a 48 sq ft pentair FNS plus filter, 1 HP one speed pump (not sure of brand), all PVC pipes. Also I have a Polaris booster pump that drives a Polaris 280.

Thanks

[kelemvor]

Have you inspected the grids to verify they're not damaged? There isn't a valve set to bypass on it, is there?

[donpolo]

kelemvor - I think some of the grids are definitely damaged. I didn't see any tears or holes but the inside manifolds (right term?) on several of them were broken or moved around a little. Needless to say, I've ordered a new set of grids. Stupid question - but exactly how would that affect the filter pressure?

Thanks again for your responses - I appreciate it!

[mas985]

Blocked or damaged grids would probably raise the filter pressure. But when the pump is running can you feel any flow out of the returns? Do you have a check valves on the suction side of the plumbing?

[donpolo]

Yes there is flow from all the returns. And no I do not have any check valves.

[mas985]

If you are feeling "strong" flow from the returns and your filter pressure is close to 0, then there are only two possible explanations.

1) You are running on low speed of a VS or two speed pump that you failed to mention. This is normal.

2) There is still something wrong with the pressure gauge.

[donpolo]

Thanks, Mark. I am definitely running a 1 sp / 1HP pump. Since I replaced the pressure gauge, I guess I'll replace the release valve too. (The gauge screws in to the top of the valve on my filter.)

One thing I did fail to mention is that I have an attached heater. I've never used it so I sometimes forget it's there. Would anything there be a possible cause?

[John M]

remove pressure gauge and turn on pump an make sure there is flow out of PS hole it could just be plugged