My high speed pump works. The heater turns on and off when it is suppose to but the low speed pump never turns off. It uses air switches to control everything but the air switch does not stop the pump. Is there a relay that's not working or could it be the air switch that it's hooked too. The airswitch that is connected to the high speed pump works.

Thanks for your help.
Doug

Air switch does not control the low speed pump -
The time clock and thermostat do.

Check your time clock, be sure it doesn't have the low speed turned on 24/7.

My timer on my AP4 is not set to operate 24/7. How can I indentify the thermostat in the control box. Is there a way that I can test it to make sure it is or is not working?

Thanks,
Doug