Re: [Amel Yacht Owners] Freshwater Pump - pressure sensing mechanical switch



In the following, I assume that you have an unmodified Amel OEM 66b (standard) or 88b (optional) fresh water pump.

Square D is worldwide and commonly used on water-well pumps throughout the world. It is a very good and reliable pressure switch with a life of around 10-15 years. It difficult to get adjusted correctly. If you search online, you will find several videos and Square D instructions. In my Amel School Book I have 10 pages devoted to the Amel OEM fresh water pump and pressure switch, which I will summarize for you.

Your Amel OEM freshwater pump originally cost 600-900 and is completely rebuildable. There are several things that could be wrong which I will list in order of probability:
  1. The wet-side of the Square D electro-mechanical valve is clogged with debris
  2. The one-way valve is either worn out or compromised with a piece of debris.
  3. There is a suction leak
  4. The impeller is broken or otherwise compromised.
  5. The impeller key has moved
  6. The Square D mechanical switches need adjustment 
  7. The Square D mechanical/electrical switches have electrically failed (poor contact).
I think that you may have started at the bottom, rather than the top of the above list. Also, it sounds like you might have made an error in wiring to the switch...there are 3 wires to the switch: 24VDC positive, 24VDC negative, and 24VDC positive output to the pilot light on the 24VDC panel.

I have more information than above, you might want to email me directly at ADMbill "at"

The Jabsco pump you discussed is basically a throw-away pump. If you go that route, buy 2 pumps so that you have a replacement when the first fails. Your AMEL OEM pump is no longer available, but very good freshwater pumps from MARCO ( are available. I would suggest the MARCO UP12/A Water pressure system PTFE gears 9.5 gpm. Plus ATX2 Stainless steel accumulator. Part N 16468013 & 16508110...about 340€ for the pump and 80€ for the accumulator...OR you could use UP6/A Water pressure system 6.9 gpm. Part N 16462013 & 16508110 ...about 245€ for the pump and 80€ for the accumulator. Email Email export "at" BTW, Amel School Clients get a 20% Discount at MARCO in Europe/worldwide and the US through their distributor

I hope this helps.


CW Bill Rouse
Admiral, Texas Navy
Commander Emeritus

Amel School
720 Winnie St
Galveston Island, TX 77550

+1(832) 380-4970

On Wed, Jul 4, 2018 at 12:36 PM colin.d.streeter@... [amelyachtowners] <amelyachtowners@...> wrote:

We have had as issue with our freshwater pump remaining on when it shouldn't, and have tried all potential remedies we could find in the files on this forum, but to no avail. Amel does not have a new one available for us despite the same switch being used on both the 53's and 54's and possibly beyond.

The pump, one way valve, and pressure cylinder are all working as designed, so we removed the housing off the pressure switch itself, and initially fiddled with the settings (by screwing both adjustment bolts in and out in different sequences) which is pretty much a black art as we have no manual showing how to set this mechanism (min pressure for pump to switch on and max pressure for pump to switch off).

Having no luck with this today we took the entire mechanical switch apart and on putting it back together now nothing works! Such is life!

A fellow Amel 54 cruiser here (previously owned a SM from new for 8 yea rs) informs me that he is aware that many other owners have done away with the original freshwater pump in favour of the Jabsco freshwater pump, (without the pressure cylinder) and actually prefer those allbeit they are slightly more noisy. Aparently they provide a smooth flow even without the pressure balancing cylinder.

With no suitable Jabsco pumps available here in Mauritius, I am looking at temporary alternatives but thought there may be some wisdom in this group about: 

1) someone has a manual for this switch and could kindly send it to us at svislandpearl@...; or 

2) some of you may have encountered this problem before, and already made step by step instructions on correct re-assembly/parts list, as well as adjustment advice for the mechanical/electrical pressure switch to work correctly; and/or 

3) some of you have already converted to the Jabsco (or equivalent) pumps and could offer some warnings and/or advice regardin g max psi model to purchase, as well as how you best plumbed it in.

In our usual style with backups for everything on Island Pearl II, I am planning to both fix/replace the existing Amel supplied unit,  and also add a second "jabsco style" option with plumbing done so that we have a quick flick over switch to use the other if either fails in future.

Fair winds & following seas

Colin, SV Island Pearl II; SM #332


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