I too have had problems with the Hayward 270T and output. It starts off strong, and then after about an hour the flow is very slight. I have a 1 HP Hayward SP1592 pump as well. By turning on/off the pump the flow is restored. Here is what I did -- you can laugh at me, it's OK... I connected the pump and return connections to the filter backwards, and ran it for about a week. The water needless to say didn't get clear. I couldn't backwash at all, so I thought I had a valve problem. When I took everything apart, that is when I realized I connected everything "backwards" -- oops. Well, the sand looked good (very clean!), and I had about 250 lbs of sands in there, so I decided to add the extra 100 lbs I needed for 350 lbs. Now, after reconnecting the the pump and return connections PROPERLY, the pump/filter seemed to flow really well. But it slows down after about an hour for some reason... any ideas? Could it be too much sand?
The flow rate for the SP1592 and the sand filter are matched really well at maximum flow rates, and slightly overkill. My goal for the system was not to load down the pump, and let it flow as hard as it can -- I get about 12 psi on the gauge when the filter is clean.
What am I doing wrong here? Too much sand or a leaky valve? I have never seen this behavior before this year.
Thanks so much -- I am an amateur and I hope I get a few laughs. Thanks for your help.