Here's the problem:
I went to clean the strainer basket from my Pentair Whisperflo WFE-3 and observed the following:
A. Flow in the strainer basket chamber is very weak and only half full.
B. The temperature got so hot inside the chamber that the plastic basket actually melted!
1. Pressure gauge was reading less than about 3 psi. Normal is about 15 psi. I just cleaned and recoated grids three days before.
2. Pump motor was running; internal thermal breaker never tripped.
3. Pool has heavy algae and was undergoing treatment.
4. Pool water level was normal and flapper was operating normally.
5. I use a Kreepy Krawley that was operating normally the day before.
What condition(s) would cause my filter to lose it's prime? It's never done this before; I've had the system in place for about 4 years.