[sheamurai]

+1 on what don.ald said above.

I had the same trouble - and it was the aqua-lifter that was the problem. The ATO has a fail-safe feature in it. It prevents the ATO from running on if the sensor gets jammed "up". I think the default setting is like 5 minutes, and can be adjusted up to 10, but its been so long now I don't remember exactly the length the time out is.

Once the time out has kicked in, it won't start up again without being shut off/on.

You can set the time out if you take the cover off.

Once I put a proper pump on the ATO, it has worked slick ever since.

I'm pretty sure I found a manual online which detailed this, but I can't find it or the link now.

But if you put a faster pump on that sucker, I am sure it will work for ya.