We have a Master Spa and recently installed a new spa pack. Everything works except the heater...none of the lights are on indicating that anythng is not working. Though when you turn it on the heater kicks on for a while and then three little dots show up on the topside control and indicate there is a flow problem. We knew this as to of the top side air control knobs have water shooting from them...what we don't know is how to fix it or where to start. Any ideas?

Might want to check and make sure all the jets are tight. When water is shooting out of the air flow control, the venturi is not working properly in one or more of the jets. I'm not familiar with Master Spa's, so I'm unsure if there's a tool needed, or if you have a 2 part jet that requires an "inner fitting" to be tightened, or what... hopefully, someone will chime in with more specific instructions. Might want to call your dealer and ask them how to tighten the jets so the venturi will work properly. (Not the actual jet housings, but the inner jet nozzle's, you don't need to drain the spa to do this)

This should also increase line pressure, hopefully enough to get rid of your flow error. But if not, a simple adjustment to your pressure switch should be all that's needed.

Good luck!