Dessalator DUO 100 Watermaker Blues

[Emerald Sea]

Need some assistance in determining why my watermaker constantly shuts-off. We use our WM continuously, more than 3 years now, making water at least every 2nd to 3rd day, change filters when required, rinse according to the manual.

Its a 2014 Dessalator DUO100 that operates from either its DC or AC motor. In both power modes is will start and as I apply the pressure to the required level, it will begin to make fresh water (green light) and then 1 - 3 minutes later will stop. I depressurize and restart but will stop again. Its been finicky like this since new but now its just stopping all the time.

We don't have any intake blockages. And when it does produce FW, its a normal flow. Discharge flow is also normal.

Troubleshooting LED Indicator lights and manual says:
- "Time out - pressure too low (check seawater intakes, pre filter and pre pump then retry)" - this is all OK
or
- " possible sensor failure or system voltage too low" - we have 14.4V at the DC motor or 220V at the AC motor - all seems OK here. Not sure about the sensor (?).

Have any other Dessalator owners come across the same issues?

Cheers

[a64pilot]

My guess is you have verified everything in the troubleshooting tree except the sensor, maybe it’s the sensor?
On edit, you have watched the pressure gauge to make sure it’s not dropping?

[Emerald Sea]

Originally Posted by a64pilot

My guess is you have verified everything in the troubleshooting tree except the sensor, maybe it’s the sensor?
On edit, you have watched the pressure gauge to make sure it’s not dropping?

The sensor may be the culprit here.

The pressure gauges typically holds steady, in the beginning of the cycle I have tweak it until it stabilizes but then it remains steady.

[a64pilot]

Is it possible to bypass the sensor? Usually you can.

[Emerald Sea]

Originally Posted by a64pilot

Is it possible to bypass the sensor? Usually you can.

Bypass: Not sure about that. Isn't it a TDS sensor, and should it be removed, it would continue to bypass SW and thus not allow the solenoid to engage for FW?

[a64pilot]

I don’t know, your post said it was a pressure sensor, pressure too low.
I do not know what kind of sensor it is, however most any thing that is automatically controlled, if you can monitor what the sensor is sensing, then you can usually safely bypass the sensor to verify it.

[aucoingc]

Dessalator is very helpful and responsive to questions. Go on-line and write them and be as descriptive as possible. You will get an answer in less than 24 hours. I have a Duo D60 and have not had the problems you describe that I could not resolve by depressurizing with the twist knob.

[Emerald Sea]

Originally Posted by aucoingc

Dessalator is very helpful and responsive to questions. Go on-line and write them and be as descriptive as possible. You will get an answer in less than 24 hours. I have a Duo D60 and have not had the problems you describe that I could not resolve by depressurizing with the twist knob.

I shot them an email. Cheers

[David B]

Originally Posted by Emerald Sea

Need some assistance in determining why my watermaker constantly shuts-off. We use our WM continuously, more than 3 years now, making water at least every 2nd to 3rd day, change filters when required, rinse according to the manual.

Its a 2014 Dessalator DUO100 that operates from either its DC or AC motor. In both power modes is will start and as I apply the pressure to the required level, it will begin to make fresh water (green light) and then 1 - 3 minutes later will stop. I depressurize and restart but will stop again. Its been finicky like this since new but now its just stopping all the time.

We don't have any intake blockages. And when it does produce FW, its a normal flow. Discharge flow is also normal.

Troubleshooting LED Indicator lights and manual says:
- "Time out - pressure too low (check seawater intakes, pre filter and pre pump then retry)" - this is all OK
or
- " possible sensor failure or system voltage too low" - we have 14.4V at the DC motor or 220V at the AC motor - all seems OK here. Not sure about the sensor (?).

Have any other Dessalator owners come across the same issues?

Cheers

We have the Duo 60. I have seen this happen occasionally, but usually due to the unit not clearing quickly enough before the management system shuts it down. I suggest opening the valve and try the flushing procedure a couple of times, then turn on again, and adjust the valve to just into the green zone, and see how you go. It could well be the sensor, but worth a try first.

Then as a test, bypass the sensors. I have not looked at the wiring diagram, but there is likely to be an under pressure and an over pressure sensor. Then then of course, there is the TDS sensor.

The TDS sensor has to see low TDS before opening the unit to flow to your tank. Low TDS means low conductivity. The sensor may be basic enough that there is no bridging resistor in it, and therefore if you disconnect the sensor, the unit will assume low TDS. That at least will prove the TDS sensor one way or the other.

As to the low and high pressure sensors, with all power disconnected, put a multimeter across each on to see which is which (LP should be normally closed at rest, and HP normally open at rest). You could then disconnect/bypass, to test. It has to be one of those sensors - or a leak that takes a few minutes running to become an issue.

I hope that helps.

David

[Emerald Sea]

David, Im away from the boat this week but will give that a try when I return. I’ll feedback. Thanks

[David B]

OK Steve - good luck with it.

David

[tinsoldier50]

My dc side clutch pulley makes a sickening grinding noise which slows and pump down and eventually shuts the unit off. Is there anyway to repair that as we are in a remote area of the Bahamas. To makes matters worse, the ac motor has failed.
How do you remove the pulley?
The ac side has a key way and it would appear that a pulley extractor would be necessary to remove that pulley?

[Bean Counter]

As noted it could be the salinity sensor. It is easy to remove. Check the electrodes and clean them. Re-insert and see if that helps.

May also be a loose wire to the sensor.

One further thing, there could be a drip type leak from the high pressure connector to the rear of the panel, and this could be causing electronic issues.

[Emerald Sea]

Originally Posted by tinsoldier50

My dc side clutch pulley makes a sickening grinding noise which slows and pump down and eventually shuts the unit off. Is there anyway to repair that as we are in a remote area of the Bahamas. To makes matters worse, the ac motor has failed.
How do you remove the pulley?
The ac side has a key way and it would appear that a pulley extractor would be necessary to remove that pulley?

Im not familiar with your grinding noise, but from what you're describing, its not good. Have you tried to turn the motor by hand and inspect where the exact location of this grinding is coming from? Are there any burning smells? Turn off all electrics before putting your hands in there. Failing this, then you will need to remove the DC motor from its mount remove the housing. Your DC motor may have failed. Or may have to replace the pulley.
How many hours are on your WM?

Note that you need to have both motors connected for the WM to work. When operating on AC, the DC motor will freely spin and the electrics are connected in such a way that the DC motor provides 12V to the WM control box. This is via the 3-strand grey cable from the DC motor to the back of the control panel and its been known for its connections to corrode up and reduce the voltage. May need cleaning or replacement. If the voltage at the panel is less than 12V it will not operate.

FWIW, there are two fuses inside the control box. You may want to check these are OK.

[aucoingc]

Originally Posted by tinsoldier50

My dc side clutch pulley makes a sickening grinding noise which slows and pump down and eventually shuts the unit off. Is there anyway to repair that as we are in a remote area of the Bahamas. To makes matters worse, the ac motor has failed.
How do you remove the pulley?
The ac side has a key way and it would appear that a pulley extractor would be necessary to remove that pulley?

I am very familiar with this Drill. You will need a new Pully from Dessalator. They ship DHL anywhere. You will also need a mechanical wheel puller to get the Pully off. Order it online. Now, the fun begins. My under banquette Duo D-60 had to be removed from the boat to get access to the Pully with the wheel puller. To do so required disconnecting the A.C. and D.C. wiring harnesses. the D.C. One is tricky; take photos before you disconnect it so you can get on right when you remount the watermaker motor platform. Dessalator is very helpful if you email them with questions and pictures. Once the Pully has been replaced the noise will go away and the functionality will return. Dessalator can ship you a new A.C. Motor as well. Pully and motor are about $500 each.