This morning I switched the pump from Low to High to do some vacuuming. To my horror a brown jet of dirty water came spewing out of the return into my otherwise crystal clear pool! The pump had been running on low for over 24 hours due to sub-freezing over night temperatures.
I have a Hayward Vari-Flo multi-port valve on a S160T sand filter. Several years ago I did a repair to the top of the Underdrain Pipe which appears intact. I did notice that where the Underdrain Pipe slides into the diffuser there is a channel where it looks like an O-ring would go but I haven't found any mention of this O-ring in forums, diagrams of the multi-port, or rebuild kits for the valve.
For the time being I can backwash & rinse before switching to the pump back to High, but would like to know what's going on here.
- What could be causing the dirt to enter the pool when switching from Low to High?
- Is there supposed to be an O-ring where the Underdrain Pipe slides into the diffuser?