Filter pressures

[tcat]

Strange phenomenon. I had a 2# check valve in my 2" line after filter, "to" the pool. I just removed it because I thought it was interfering with flow on low motor speed. Pump is 12" above water level so I saw no need for it.

Filter pressure on low with check valve: 8 psi
Filter pressure on low without check valve: 12 psi

I would have though it would drop to 4-6. Does this make sense? Possibly more water is moving without the check valve, so filter is seeing more pressure? It is a pressure valve on top of the filter (not a vacuum valve), right?

 

[mas985]

Usually, reducing head loss after the filter gauge will reduce pressure and not increase pressure. Even with the increased flow, the return head loss (pressure) is still lower than it was before. So either something else changed or your gauge is not working properly.

 

[tcat]

Yeah, odd. Before and after was only about 20 minutes, so must be my gauge. Will look into replacing it. Does go to zero when off, 29 on high, 12 on low.

 

[mas985]

You might also check the plumbing downstream since you modified the plumbing perhaps something got stuck somewhere.

 

[tcat]

Should be no issues there. Just 2 saw cuts with pump off. Water from 4 jets on high or low (pretty slow on low). Not much skimmer action even with drain line shut (but is sucking). Plan on cleaning filter this weekend, but shouldn't be to dirty.

edit: My low pressure is back down to 8. I added a Poolskim which opened up one of the returns much more than it was, so pressure side restriction went down. Filter pressure seems very sensitive to return opening. All seems to be running fine, so not going to worry about it. If pressure goes up to 10 I'll clean the filter.