So far this year, amongst other problems such as flaking paint after the winter, and faulty lcd hour meter displays, also after the winter, we have had more than our share of leaks in the plumbing system. I meticulously drain the water system before the winter lay up, so I can't blame the problems on freezing. The first ones I noticed, early on, were identified as loose joints in the HEP 20 fresh water system piping joints. The problem showed up when the water pump started to run, for only a few seconds, every couple of hours, indicating that there had been a drop in pressure. The leaking joints were found under the bathroom floor, and had damp patches under them. I dismantled each joint, checked the components, and re-tightened them, and the floor around them dried up. Then of course we had the leaking Alde central heating boiler, which turned out to be a major job. Last weekend, the water pump started to operate for a few seconds every couple of hours once more. Not again!
The isolation valve on the stainless steel water tank, which is located under the bow, was closed, and the HEP 20 joints which connect the pump were released, and replaced temporarily with 15mm blanking ends, so that any remaining water in the system didn't run into the bilge while the pump was disconnected.
Once off, and on the workbench, it was a simple matter of releasing the screws that secure the diaphragm chamber to the pump, and sure enough, there was evidence of a water leak. The cap is sealed to the rest of the pump by a small 1mm white closed cell foam seal, which had blackening on the underside - evidence that water had been lodged there, and then leaking out to the outside world. I didn't replace the gasket, preferring to leave it in place, and run a bead of clear silicone sealant around the mating edges of the chamber before putting it back together. I took care not to use too much, and also ensured that any excess sealant would be squeezed to the outside of the pump chamber when re-assembled. If any of the sealant had found its way into the pump chamber, when set, could cause blockage problems if it broke loose in the future. The rebuilt pump assembly was then put back into the water circuit, and left for a couple of hours before turning the water supply back on. This has cured this particular problem, I wonder what will be next?