Hi - I've got a 1999 Marquis Reward CS. Changed water about 1 week ago. Now, spa heats to set temp. then shuts down with "FL" error code. No buttons work, no flashing, just 'FL". Everything seems to work fine until the heater turns off - all jets seem ok, both pumps work, no noticable difference in flow, etc. Once I get the "FL" code - if I switch the breaker off then back on (after 10-15 seconds), then everything seems to work fine again - until the set temp is reached (and heater shuts off). I've checked all the valves that I can find and they're all open, tried running without the filter cartridges installed, no difference. From other things I've found, this sounds like a failed pressure switch, but based on the picture I've seen of this switch - I can't even seem to locate one. I also thought I read somewhere that this spa may not use pressure switches. I'm confused. Can anybody offer any suggestions?

Thanks

Can you post a picture of your equipment or the make and model of your control pack?

Here's some pictures. I'm not sure about the control pack, I think it's made by Balboa - I know the topside control is made by Balboa (specifically for Marquis). Please let me know if there's any other info I can provide to help shed some light on this. Thanks!

Great pictures, thanks!

The silver box over the pump on the right is where you'll find your pressure switch. FL may just be a generic flow failure for your system. When the spa reaches temperature, your heater and pump cut off, but your pressure or flow switch may still be telling the system that there is water flow.

If you have a pressure switch, it should look something like this. The knob at the top is adjustable. As you tighten it down, it takes more pressure to close the switch. Yours may be set so that the weight of the water alone is enough to close it. Or it may be shot altogether.

To calibrate it, attach an ohm meter or continuity tester with the pump on low. Tighten the adjustment screw until the circuit opens, then turn back a quarter turn so that it closes again.

You may also have a flow switch instead. In either case, take a look at the wiring diagram on the back of your control panel cover. It should label one of the small gray 2-wire cables as a flow or pressure switch connection. Then you can just follow the wire. If you have a flow switch, it will have to be pulled and checked for debris that might be holding it shut.

That did it! It was indeed a pressure switch. I tightened the calibration knob and all seems to be well now, it's been running all night without a dreaded "FL" code. Thank You spishex!!

You got it! Enjoy!