DE filter low pressure, low jet flow

[yeazellpa]

I recently purchased a house with a pool. It has DE filter. The pressure was high on the filter housing about 20PSI so I backwashed the filter. I primed the pump by letting water squirt out the relief valve and then closed it up. The pressure on the gauge read essentially zero. I slowly added about a pound of DE and I noticed the flow out the return jets dropped dramatically. The pressure on the filter housing was still
zero. I suspect there's a clog somewhere. Any ideas?

[czechmate]

20 PSI alone does not constitute high pressure.
Pressure, or rather backpressure of the piping, rise, filter elements etc., all determine the starting pressure of your cleaning system. Usually the backwash is recommended (by manufacturer) when pressure is 10psi over starting pressure. It is lot more efficient to do it after 6-7psi rise. (Your cycle is getting longer and you not only waist electricity and money but your circulation on bottom is too slow to move debris toward the main drain as well).
Zero pressure is not attainable as long as anything flows thru the filter can.
You either shut of completely on the filter side, or your gauge is not working.
Since you used the bleeding cock it points to the gauge.
Also, check if there is loss of water in the pool.
If the pump is running and the water has no place to go you will cook the seals pretty quick.

[yeazellpa]

Thanks for the response. I found the problem. The leaf trap in front of the pump was horribly clogged. I had to borrow a wrench to get it open so I suspect it hasn't been opened in a long time. Everything seems fine now. After adding the appropriate amount of DE, the clean pressure is 14 psi and the flow out the jets is high.