Waterway All-In-One Air Blower Check and Drain Valve

The best all-in-one air blower protection check valve available!
Waterway 1.5" / 40mm air blower check valve assembly with built in drain valve.
Install horizontally in the air blower loop plumbing 

If water manages to get past the built in check valve, it will drain out via a 3/8" (9mm) barb which drains off below a ball float.
This drain valve remains closed in normal operation. if water gets past the check valve it will lift the floating ball and water will drain via the barb.
Connect 9mm clear tubing to the drain barb and run out of the spa cabinet.

1.5" socket towards air injectors
1.5" spigot towards air blower
9mm barb drain