Re: Marco UP6/E pump and MASS+



I understand that you are saying when the MASS switch is moved to "+"  (positive) the light turns ON.  Correct?

This means that there is a connection between 24VDC Positive and Bonding. When a pump is involved it is almost always because a pump seal has failed, allowing water to penetrate and cause a connection between bonding and positive 24VDC. (If the light comes ON when the switch is in the Negative position, the connection is between Negative and Bonding,). Saltwater creates a stronger connection than freshwater.

In your situation, most likely saltwater has probably caused this "connection" between bonding and 24VAC Positive. I think the first place that I would look very closely is the ethernet type connection between the pump and the optional electronic monitor (male & female). I believe you will find the fault there. Clean the connection(s) with freshwater, then alcohol.  Then next, I would open the pump electrical connections. What I would look for is salt crystals. Remember, these could be microscopic, especially with ethernet connections (male & female). Let me know what you find.

Regarding the function of the 24V panel light, Marco owes me an explanation. I asked for this some time ago. I will email them again today and will post the answer to the group.


CW Bill Rouse
720 Winnie St
Galveston Island, TX 77550
+1(832) 380-4970

On Wed, Mar 6, 2019, 8:41 PM Scott Nguyen <scott.nguyen@...> wrote:

Slight typo - I had a small leak from the waterMAKER hoses so some salt water got on the Marco pump.

On Wed, Mar 6, 2019 at 10:32 PM Scott Nguyen <scott.nguyen@...> wrote:

As you now, I'm using the Marco UP6/E pump for domestic water and have been doing so for almost 6 months now. I regularly check the Mass- and Mass+ switch on my A54 to ensure no electrical leaks.

This evening, I checked and got a Mass+ light, clear and bright. Luckily, I was able to quickly isolate it by turning off the freshwater water pump on the 24v circuit breaker panel. 

As you may recall, we had some issues with the smart sensor positive lead (between smart sensor and pump itself) keeping the 24v panel freshwater pump light on permanently. We couldn't figure it out so I just moved on and dealt with the 24v panel freshwater pump light being on all the time. To test to see if this was causing the Mass+ fault, I cut the wire. The 24v panel freshwater pump light obviously is no longer on, but the Mass+ light remained.

The only way I could get rid of the Mass+ light was remove the bonding wire from the pump body. Do you know what may cause the Marco pump to all of the sudden create continuity between + and the pump body? 

I had a small leak from the waterpump hoses so some salt water got on the Marco pump, but I can't imagine that causes the pump to be + energized? 

What would you do in my position? Thanks!


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