Watermaker : Unjam the low pressure pump
The low pressure pump is a sensitive device, due to the fact that it works with seawater. However it is reliable and easy to restart if one knows the necessary handlings after a long periode of inactivity. It is for example the case during a restart of the watermaker. By the way, the procedure is very similar for the air conditionning sea water pump.
The first possible operation is to turn manually the impeller with a flat screwdriver. The second is to purge the pump from its air, to help it to prime.
Manual rotation of the impeller
There are two types of pumps on your boats, either on the AMEL 54, 55 or 64. It can be blue or black.
On the black one, you can unclip the plastic cover taking place behind the pump, and turn manually the cooling fins. Those fins are connected to the same axis as the impeller, which means you will therefore be able to move the impeller and free it from impurities or rust. The best is to turn those fins clockwise compare to your position. It is the normal sens of rotation of the impeller.
On the blue model, the theory is the same except that you can’t unclip the cover. It is screwed on the pump as you can see on the picture below. The easiest way to turn the impeller will be here to turn the axis in the middle of the cover with a small flat screwdriver. You will need to find the hole in the middle of the cover, then find the groove on the axis where your screwdriver will take place. You can then turn the impeller a few times.
Once your rotations done, you can try to start the watermaker. Don’t forget to check first that the low pressure pump fuse is on. It is located behind the control panel of the watermaker. If the pump starts (noise and vibrations), but the pressure visible on the low pressure manometer does not reach the green zone, it means that the pumpe is not working well. It can be because you didn’t turn enough or because air doesn’t allows it to prime.
If the impeller shows some troubles to start, a current operation on the black pumps is to unscrew slightly the 4 bolts of the impeller cover. They are located on the front of the pump. The pressure on the axis and on the impeller will be released and the pump will start easier. Caution : some seawater will leak from the cover, do not forget to place a container below the pump before.
Air bleeding the low pressure pump :
A second possible operation is to prime the pump with the air bleeding screw. It is shown in the yellow box on the picture below :
Just release the screw before starting the pump. Do not remove the screw completely as you will need to be able to tighten it as soon as seawater comes from the hole. It means that air as been chased from the hoses and the case.
