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I have a vacuum pump servicing the two forward heads on an 1980 61' Hat cpmy. Still learning the systems after purchasing the boat just over 2 weeks ago. Within the last 2 days the diaphram vacuum pump has started to cycle about 8 or 10 pumps every 3 minutes. I have tightened all the double clamps, hoses appear in good shape an show no visible leaks. I have listened for air leaks at both heads and below deck with out an obvious leak. Any thoughts or suggestions would be appreciated. Thank you
Does water stay in the bowl? If not the problem is with the ball seal, usually some debris preventing a good seal
If water stays in the bowl, then you next suspect will be one of the duckbills in the pumo. Two on the inlet, two on the outlet. They re a maintenance item and usually need to be replaced every 5 to 6 years. Easy job if you have good access. Loosen up the clamps, unscrew the fittings and replace the duckbills. I usually put liquid soap on the DB flanges to prevent them from deforming and dont overtighten
I dont like have one pump for two heads. You loose redundancy and it makes troubleshooting harder. When checking for leaks, there will be an extra DB in line between the pump and each vac tank
The plunger in the pump may be worn out. Order a rebuild kit and some scale remover. The rebuild kit is $220.
Pull the pump and take it apart. Soak the body in descaler until clean. Rinse and reassemble using new parts.
Once you get over the "yuck" factor, it really not a tough project.
The plunger can fail and leak when it does it spurts leaks black water... very noticeable. I v never seen one causign a vac leak as the pump body is pressurized on the down stroke
If there are no vacuum leaks at the fittings, as Pascal said, the first suspect is the seal between the ball and the bowl so check if the bowl is retaining water.
Next would be the duck bills. Much farther down the likely hood scale are the vacuum switch on the tank and the pump bellows. The manual is available online, and Environmental Marine in Ft Lauderdale is an excellent source for advice and parts.
Thanks to all your suggestions and I will go to work and get it done. Thanks again, PJ61
Replaced the 4 duck bill valves today and seemed to resolve the cycleing issue. Thanks to all for sharing your knowledge and suggestions. PJ61
Sorry I was late to the conversation. Fixed mine a few months back with your same solution. If the duck bill valves are the least bit deformed or dry/hard they will not hold a vacuum.Quote:
Originally Posted by PJ61
I also rebuilt both of my heads while I was at it. The way I looked at it, if one set of rubber in a system is bad, the others aren't far behind. Would rather deal with the heads at the dock rather than out on a trip! The seal kits for the heads were < $100/ea