Spa Draining when Equipment Shut Off

[parisvienna]

Woke up this morning to find that the spa, which spills over into the pool, had lost about 1/3 of its water overnight.

Equipment was in service mode with all equipment shut off at 11:00 pm. The equipment had been in service mode and main pump running 24/7 since last week when I started shock process. The pool passed all three of the shock tests yesterday morning, so I decided to shut the pump off for the night.

Before I left for work, I kept the equipment in service mode and turned on the pump. The spa began to fill via normal flow. My wife says that the spa is now full and spilling over.

Any ideas on what might be happening with the spa?

Thanks

 

[JasonLion]

There is a check valve on the pipe that sends water to the spa, and a three way valve that determines if water returning from the spa goes to the pump or not. If either of those valves is leaking (dirty or broken) they can allow the spa to drain down when the pump is off. Problems with the check valve are a little more common.