2004 Marquis Reward pumps question?

[sregnar]

Hello, I inherited a 2004 Marquis Reward with my new home, and i've been working on getting it back up and running. New heater element fixed the breaker issue, new topside fixed the broken LCD, now im getting a "dr" error, so i just bought 2 new heater sensors. Here's my question, my spa has 2 pumps, a mp-130 and a mp-160, i know the mp-160 is 4.2HP, 2 speed, the other is 3HP, not sure on speeds for the mp-130. What i'd like to know is, what does each pump do individually? How can i test to see if one is working properly without removing it? If my "dr" error(basically refers to the temp in and out of the heater area) is because of lack of flow through the heater, which of my pumps would be responsible for this? Im trying to understand how this whole thing works, and im struggling to understand exactly what each pump does. I can tell you that the topside jet control has 2 speeds, and they both work, water flow in the spa changes from low to high, but i assume that could all be done by one pump. Any info would be appreciated. I'll include a link to the manual, thanks for any responses.

http://www.marquisspas.com/documents/2004/MS_03_OM.pdf

[Vinny]

I'm not a spa tech but will give it a shot at explaining.

Based on what you linked, pump 3 which is the MP160 is the pump for the heater which is in Item #1. You have 2 gate valves to isolate that section (pump, heater and ozonator) to service that area without draining the spa. I believe the water gets sucked into the center of the pump and is pushed out the top with most of the water going through 1 with some going to the ozonator. If one or both of the gate valves are closed the pump will not push water anywhere. There is probably a flow sensor that will see water flowing in order to have the heater come on.

How to test - make sure the gate valves are open, make sure the new temp sensors are in correctly and locate the flow sensor "just in case". Power up the tub, the sensor should call for heat and the pump should come on. If everything is OK the tub should start heating, if not check that flow sensor if the pump is coming on. If the pump doesn't come on measure the voltage (if you can get to it) going to the pump. BE VERY CAREFUL IF YOU NEVER WORKED AROUND ELECTRICITY!!! If you have voltage - pump is probably no good, if no voltage - need to find out why.

[sregnar]

Thanks! I fired it up with the new sensors, and it gave me the dr error again. there's no flow sensor, just 2 heat sensors and the difference in temp in those sensors indicates flow for the heater. i think what might be happening is airlocked pumps, because both pumps are cranking water into the tub. i popped off the top fitting on each pump and they both started breathing air, and then pumped harder. unfortunately the gasket on the pump that doesn't have service valves came off, so i had to drain the tub again, and ill get it repaired dry and refill. hopefully bleeding the pumps will increase flow and get me on track. ill post when i get it filled and running again.

[Vinny]

Try filling the tub from the filter compartment. Take off the filter and stick the hose into the port, this will cause the water to enter the pump and kind of force the air out. Make sure that even though you opened the gate valves that they actually opened (don't know how to tell). I've never got an air locked pump so I am useless for telling you how to get rid of it ... usually during a fill the pumps will burp air and work.

[sregnar]

yea i do fill via the filter area, im going to fill and then run with the junctions cracked open a bit to try to help prime and purge air.

[Vinny]

Those junctions should always be opened unless you are servicing the spa. I don't have any gate valves on my tub so it won't harm anything to keep them open all the time.

[sregnar]

no sorry, the slice vales are open, the junctions im referring to are the PVC pump fittings, im loosening them to let air out.

[sregnar]

So I may have solved the issue, and it seems too easy. When the spa is turned on the pump that's NOT directly plumbed to heater runs, and the other that is directly plumbed to the heater only runs when you turn the jets on manually. I was getting dry errors and heater flow low errors. So I powered down, unplugged the pumps from the board and reversed the plugs. Now when powered on the pump that flows directly to the heater is running and the other is not, meaning I'm getting consistent water flow through the heater, hopefully solving this issue for good! Unfortunately one of the heater PVC junctions is leaking so I just siliconed the exterior of the PVC, once dry I'll fire the puppy up!

[MarKee]

Sounds like your heater gaskets are worn out, you should replace them.  The silicone is probably a band-aid fix and it will likely start leaking again.

[sregnar]

Heater gaskets are brand new. The silicone was a bandaid and it still didn't work, so I closed the slice valves and cleaned off all the silicone. I took the split nut off and added a good amount of pipe dope to the threads, and put it back together. Seems to 99.9% leak free, tiny bit of moisture after an hour. The good news is that my pump switch fix worked! And the tubs been running and heating flawlessly for a couple hours!

[sregnar]

Just updating for those who've helped or read, tub ran and got up to operating temp, and is performing like new. Thanks to all for helping. Next is chemical maintenance....