I just bought a house with an American Spas built in 1990. It has a HydroQuip Designer Series spa pack with air controls. I recently fixed a few issues and it's running better than ever except I have a problem with the air bubbles.
On the top control panel, I have two buttons, one for what I assume would be the light (that doesn't work) and one that cycles through four jet settings, I call them jets "A", jets "B", both sets, and off. Then there are two rotating dials that control the air bubbles, one for each set of A & B jets. The jets and the air bubbles all flow strong when turned on. The problem I'm having is that on set A jets, the bubbles don't completely stop when I turn the dial to "off", instead they drop to a pulsing on/off cycle where they will push out a small amount of bubbles about once a second. This is accompanied by an annoying sound with the same pulsing frequency. If I put my ear to the pipes I can hear air rushing through one of them.
I am not sure what's causing this. The system must be drawing air in from somewhere. Does this mean I have a leak in my system somewhere? If so, how can I locate it and patch it? Possibly the dial is not closing itself completely?
Thanks for your advice!