Need to change plumbing from copper to PVC, get rid of drain

[mas985]

There seems to be some inconsistancy in the numbers somewhere. With the pump you have and the plumbing you describe I would have expected a filter pressure close to 22 PSI (78 GPM @ 69' of head) and not 12 PSI you are seeing. So this means something isn't correct.

First, I am using the pump head curve D in this document. See if your manual shows the same.

Second, are you fairly confident in the filter pressure gauge? How old is it? Does it go to zero when shut off? When you tap the gauge, does the pressure change?

Another possibility is that the impeller is either slightly clogged or damaged somehow so it doesn't follow the pump head curve anymore. This can happen with older pumps so it is difficult to calibrate the existing plumbing under these conditions but if you can confirm the head curve and pressure gauge, I can make adjustments for the derated impeller.

 

[Laker4ever]

The pressure gauge...not sure, but seeing it rises as the filter clogs and then to drop...
It might have some bad offset, but it does drop to 0. I'm not sure, but maybe the fact that i have a leak in the suction line, where the system pulls in air in addition to water, is the fact that the numbers are off. I can verify that when the pump is not fully primes, the pressure is about 6-7 PSI, and when primed, it gets to 10-12, (again when it is clean filter with new DE)
The pump is making noise more than it should. Because the water leak, i think it was working with low/no water and might have damaged the impeller to shift the curve somewhat.

 

[mas985]

Do you still have a lot of air in the pump basket when operation at 10-12 PSI? If so, another possibility is that you may have a partial suction side blockage. That will also reduce the flow rate and filter PSI.