|Pressure Pump on left|
I confirmed that the pump was OK by supplying it with power from the nearby house battery. Then I tracked the problem to low voltage from the main battery. I changed a connector on the main feed wire and that brought up the voltage to more than 13.5V. However, the pump would still not work.
After spending more time testing out the connectors and still measuring the required voltage I conclude from intuition more than electrical knowledge that the voltage from the feed wire was only a "surface" effect that disappeared as soon as a load was put on the circuit. This suggested to me that it was time to bite the bullet and replace the 2-core wire from the main bard to the pressure pump. I needed to do this anyway because I had noticed to my intense annoyance that the feeder cable was of ordinary house wire rather than the tinned wire required for marine use. The individual wires at the ends of the cable were black from corrosion, and the corrosion had probably crept through much of the cable run
Swapping the wire was not an easy task, largely because the installation of the side batteries in New Zealand had required new flooring that covered up sections of the wiring paths.
I purchased 10 meters of proper tinned wire and got to work
I used the old cable as a pull-through to get the new cable from the main board past the nav table into the port bunk space, saving me hours of work. It was in the port bunk area that I found two sections of corrosion in the cable.
I soon gave up following the old path and routed the new wire along the upper part of the starboard side of the bilge, then to the pressure pump in the forward end of the bunk space
By 1 PM of the second day the job was completed and I spent an hour putting the cabin back together again. The seat bases had to be put back into position, then every seat cushion, then 5 sections of the cabin flooring.
This shoddy wiring had cost me plenty, not just the hours of work but more important, the replacement of a pressure pump that probably did not need replacement. Fortunately the old pump is intact on my workbench because I have not had time to do the planned post mortem on it. If it passes the workbench test I'll keep it as a spare.