Not sure how I'll go explaining this, but here goes...
Short story is, my pump isn't pumping water. I first noticed this morning when it didn't come on at its scheduled start time. When I went down to check what was wrong, I saw the SWG had a "no flow" error and had turned the pump to the manually off setting. The pump is a Viron (Astral Pool) P300 3 speed. All of the below was done on the turbo setting.
Now I'm the first to admit I have no idea when comes to pumps and dealing with airlocks, priming and the like. I'm sure there's no blockages on either side, because when I open the lint pot lid I can get water to flow freely from both the suction side and the filter side. I opened the suction side tap with the lint pot open and let the water flow freely to hopefully let out any air that might be trapped on that side. I then did what the pump manual said to prime the pump, which was close the suction side tap and let the lint pot fill completely from the filter side before replacing the lid. I also bled any air out of the cartridge filter. At that stage everything looks OK including the salt cell being filled with water. The pump manual says if a prime can't be maintained after 3 attempts (and all suction connections are sealing well), then a check or foot valve is required to hold water for prime... what does that mean?
Here's where I'm hoping the reproducible symptoms might mean something to a seasoned veteran... when I restart the pump, the water level in the lint pot drops rapidly to just below the suction side opening and the water flowing into the pump from the suction side starts flowing in kind of spurts, but the water level does seem to be slowly rising. The flow through the salt cell is low, but the water is moving. After about 30 secs to a minute, things start to sound really promising and the water level in the lint pots starts rising a lot faster. The flow through the salt cell starts flowing much faster too. Then all of a sudden the pump gets louder and the water drains almost completely from the lint pot and the flow from the suction side pretty much stops completely. At this stage there's no flow through the salt cell, so I turn the pump off manually. When the pump turns off, water seems to flow back from the filter side to fill the lint pot, but none seems to come through from the suction side (I think). With a bit of mucking around I can reproduce this sequence.
I work most of the daylight hours so I haven't been able to have a good look around for leaks yet. A good majority of the suction side pipe is under a wooden deck so I have fingers crossed there's nothing wrong under there! The system is still only about 4 months old so I'm optimistic that a leak isn't the most likely cause (wishful thinking?).
So what does everyone think?