Hello all. I have an '89 Pacific marquis spa with a 2 speed pump that I inheritted with the house I just bought. Through reading this forum, I've pretty much figured out how to operate this thing. I contacted Marquis and they sent me a manual for a similar but not exactly the same model, which was semi-helpful. Here's the only problem I have now. Maybe someone here can point me in the right direction.

The circ pump runs fine. it appears to operate 24/7 no matter what the timer setting is. I believe I have the bypass switch in the right position but Ihaven't found a convenient way to open up the controller to ohm the switch out yet. I'm ignoring that phenomenon for the moment.

When I turn on the jets, it runs fine for about 10 minutes and then everything, including the circ pump, shuts off. The blower motor will still operate and the lights stay on. When the pump shuts off, it is followed by this tapping/banging noise that continues for about 30 seconds. then all goes quiet. After about 10 minutes, everything begins operating again. If I put in back in circ mode, it will be as happy as a clam. if I operate the jets, it will run for about 10 minutes and then shut down again, followed by the tapping noise again.

I'm assuming some sort shutdown is activating due to excessive heat or current. Does anyone recognize these symptoms? Based on the age of the spa and the rusty appearance of the controller, I suspect I have a new controller in my future. I'm wondering whether I'll need to replace the pump also.

Thanks for any help you can provide.

I'm still hoping someone will give me some help. To update you, I opened up the control panel. Other than being a bit rusty, everything seems tight and operational. Based on my symptoms, I'm assuming that the pump's internal thermal breaker is opening from the pump overheating. Assuming this is so, I'll just replace the pump. No problem. The thing that has me puzzled is the fairly loud repetitive banging noise that follows when the pump shuts down. It goes on for approx. 20 "bangs" before it stops. The pump is them off entirely (including low speed). The blower motor will still operate and the lights still work, so there is power to the controls. After about 10 minutes (and presumably after the pump cools) it will come back on and operate normally until it shuts down again. Then the whole thing repeats. The tub is operating with the low speed pump on 24/7 and that seems to be fine. I'd hate to replace the pump only to find out it is the low/high switch or something else. Any body have any guesses?

Look for a bad swing valve if installed discharge side of the pump. If you have one and the flapper is broken off the pump may knock. This could let the circ pump run ok while causing the main pump to over heat and trip the thermal overload due to the indifference in flow rates.

Heaters can also knock when the runaway and start to boil.

Maybe this helps ?

Pork

Thanks Pork.

I'll check the valve situation. The heater is turned off, so I'm assuming that's not part of the equation. It would be great if i just had to replace a bad valve.

Well it's just a guess since very few manufactures use swing valves on their plumbing. I wouldn't rule the heater out. Don't run the heater until you figure it out.