Re: [Amel] watermaker feed pump problem (160 l/h)


Roque
 

Just in case, have you checked the pipe that takes sea water to the pump?
I experienced the same general symptoms (except for the manual override)
and it took me a long while to find out that the pipe was clogged with
salt crystals and algae. The crystals are light coloured and the pipe was
so uniformly clogged, that only a close inspection solved the problem.

If this is not the culprit in your case, at least you will end up with
preventive maintenance job done......

Roque

S/Y Atica, Amel 54


2012/11/17 sabbatical3 <mark_pitt@...>

**


Gary and Kent:

I belated thank you for your suggestions. With the help of Martin at
Dessalator Espana, it has finally been established that the pressure sensor
is at fault. The problem with the pressure sensor is intermittent, making
diagnosis more difficult.

My question is: how much risk is there in running my water maker with the
pressure sensor disconnected. I have run the water maker hundreds of times
in the last 6 years of cruising, and only once has it shut down
unexpectedly. I would rather not wait for this very expensive part in
Malaysia -- perhaps putting it off to the end of the season. Comments?

Thanks again.

Mark Pitt
S/Y Sabbatical III, ASM #419 currently at Rebak, Malaysia

--- In amelyachtowners@..., amelliahona <no_reply@...> wrote:




I believe Kent is on to something here. The only logic that will cause
the red light to come on is High Pressure. Kent, if you have the original
logic board, salinity does not cause a red light and bypass activation.
That was the way it was supposed to work but that circuity was never hooked
up at the control board level. ( see previous post about this brouhaha )

If the blue manual override lever on the BP pump (low pressure feed
pump) 220 volt control relay [hereafter called the 220 VAC BP pump control
relay] (the large relay in the box, NOT the small 24 volt control really on
the logic board) causes the pump to operate normally, then that totally
excludes any problem with your pump or 220 volt power to the pump.

The pumps use two relays to control them. We refer to this a "ganged
relays". The theory is that a small relay is controlled by some sort of
logic, and that small relay then controls a larger relay that is capable of
heavy electrical loads. In the case of the Dessalator original 160l/hr
control circuit, the logic is provided by the high pressure switch. It was
supposed to have a salinity sensor also providing logic but we know that
circuit was never utilized on the original installation. That was corrected
by Dessalator with their second generation control board. The small relay
(24 VDC BP pump control relay) is Relay #1 on the circuit board, and the
large relay (220 VAC BP pump control relay) is the one with the blue lever
in the electrical box. To trouble shoot this you need to test each section
of these components in a logical manner. The 220 VAC circuit breaker must
be on and the rotary control switch on the water maker must be on to test
the system. The rotary switch just supplies power to the control circuit
board. PLEASE BE CAUTIOUS AS YOU DO THIS TROUBLE SHOOTING BECAUSE YOU WILL
HAVE TO HAVE THE WATER MATER BREAKER ACTIVATED AND THE WATER MAKER ROTARY
CONTROL SWITCH ON AND THERE IS HIGH VOLTAGE IN THIS BOX DURING THOSE TIMES.
DON'T KILL YOURSELF!!!)

Did I understand correctly that you "do not" have 24 volt control power
to the coil of the 220 volt control relay? You should have 24 volts at that
location any time the rotary water maker switch on the water maker control
panel is in the "On" position (measure each leg of the coil referenced to
ground while the water maker rotary switch is turned on and the water maker
CB on the 220 volt panel in the galley is activated). Alternatively verify
that you have 24 VDC on Pin 8 of Plug 1 on the control board (see the
schematic in the files section under Dessalator Technical Info >
Schematic-Dessalator Board) The control circuit for the 220 volt control
relay should have 24 volts on it anytime the water maker rotary switch is
turned on. Actual control is by completing the circuit by providing a sink
to ground via Relay 1. The mere fact that the BP pump starts, even
momentarily at times, would indicate that you have a logic problem (i.e.
the HP switch is defective), not a control relay problem. However, to
further test:

1. Verify that the 2 amp fuse in Fuse holder #2 is ok. In fact, check
the continuity of each of the control board fuses. Check continuity with
your ohm meter, don't just depend upon eyesight. Fuse 2 is the ground sink
fuse for Relay 1 which is the control relay for the BP pump relay (low
pressure pump).
2. Verify that you have 24 VDC on pin 5 of PLUG 1 of the control board.
3. Verify that you have 24 VDC on pin 8 of PLUG 1 of the control board.
4. Verify that you have 24 VDC on one of the coil pins at the BP pump
220 volt control relay.
5. Using a test lead wire sink pin 9 of plug 1 to the base of Fuse 2
(use the inboard side of the fuse holder, i.e. the end that faces all the
electrical components so that if there is a short of some sort it will blow
this fuse ) and see if this then activates the 220 VAC BP pump control
relay. If providing this ground activates the 220 volt control relay then
the problem is that the logic on the board isn't activating the 24 volt
control board BP pump relay (Relay 1).

I do not remember if the High Pressure Sensor is a normally open or
normally closed switch but it is really the only logic input to the control
board. Therefore if you either open that circuit or short that circuit
(i.e. disconnect the wire to Pin 8 or Pin 9 on PLUG 2 of the control board
to open the circuit, or short pin 8 to pin 9 of PLUG 2 to close that
circuit) you should be able to verify the logic integrity. Pressure
switches do fail and I am guessing that your switch is faulty. You could
remove the pressure switch and test it's continuity with an ohm meter using
compressed air to activate the switch to see at what pressure it operates.
If you do this or can confirm if this switch is a NO or NC (normally open
or normally closed) switch it would be helpful. Gentle tapping on a
pressure switch at times may assist in troubleshooting by breaking
something loose.

One last question, If you provide a manual override of the BP pump
control relay with the blue lever, does the high pressure pump start
normally even though the red LED illuminates?

I hope this helps. If all I have done is add to the confusion please
feel free to advise so.

Gary Silver
Amel SM #335

--- In amelyachtowners@..., karkauai@ wrote:

Could you have a bad pressure sensor that is shutting the system down
due to perceived high pressure? That would cause a red light and shut down,
but wouldn't explain why it works on manual. I'm not on my boat so can't
look at the owners manual. What else causes a red light and shutdown
besides hi pressure? I think bad quality output causes a red lite and
switches the output to go overboard, not shut down.
Kent
SM 243
Kristy
Sent from my BlackBerry® smartphone powered by Alltel

-----Original Message-----
From: Mark <mark_pitt@>
Sender: amelyachtowners@...
Date: Sat, 20 Oct 2012 11:17:12
To: <amelyachtowners@...>
Reply-To: amelyachtowners@...
Subject: Re: [Amel] watermaker feed pump problem (160 l/h)

Eric:

None of the circuit breakers in the control box tripped.

Best,

Mark

On 10/20/2012 11:15 AM, Sailormon wrote:
Mark,

Do any of the circuit breakers trip in the control box?

My main one was always tripping until I upped the amperage by
turning the
red screw on the breaker.

Fair Winds

Eric

Amel Super Maramu #376 Kimberlite





_____

From: amelyachtowners@...
[mailto:amelyachtowners@...] On Behalf Of sabbatical3
Sent: Friday, October 19, 2012 11:13 PM
To: amelyachtowners@...
Subject: [Amel] watermaker feed pump problem (160 l/h)





Hi:

I had the shaft of my feed pump shaft reground and new seals
installed. I
left a marina last week and tested the watermaker at the first
anchorage. It
worked great -- the low pressure gauge was well into the green
(before it
had been orange) and the system produced good quality water (I have
an
inline sensor with display). However, after 10 minutes the system
shut down
with the red alarm light on. Since then, the best I can do is get
the feed
pump to come on for 2 seconds before it shuts down and the red alarm
light
comes on, and most of the time it does not start up at all, just the
red
alarm light comes on.

I have tested all of the electricals on the pump and in the control
box
(including the logic board) and everything seems fine except that I
am not
getting 24V power to the relay. If I use the blue "relay manual
activation
lever" the pump works and seems to produce a good flow of sea water.
The
capacitor on the pump tests fine, and in any case, the pump runs
well with
the manual over-ride, with the pressure gauge well into the green.

There was a big fish stuck in the sea strainer after the system shut
down
the only time it ran with the renovated pump, but removing it did
not make a
difference. I am not sure how this might matter.

Any ideas on how to troubleshoot this? The boat has just come off of
10
months on the hard in the tropics. I used a very dilute pickling
solution
before leaving her.

Thanks for any ideas.

Mark Pitt
S/V Sabbatical III, ASM #419
currently in Penang, Malaysia





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