When we bought Ophelia in the spring of 2017, we were a little perplexed by the Freshwater System. It seemed that we could only draw water from 1 of 3 freshwater tanks and there was a possible bad pump, along with a couple air leaks, which can reduce pressure or airlock both pumps. Suffice to say, it worked well enough off the MID-water tank alone (150 gallon tank), that this job fell to the bottom of my rehab list! 2 years later, I have finally tackled the problems and upgraded the system! Luckily we have not been crossing any oceans and the water maker has been working flawlessly! That has allowed me to kick this problem down the road the last two years.
Ophelia has two Fresh Water Pumps, running in parallel for redundancy, should the main fresh water pump break or stop working. These two pumps are fed by a manifold. The Manifold brings together all 3 water tanks plus the water-maker's water. The manifold allows me to specify which of the 3 water tanks to draw from. Other N50's may be slightly different, with some having 4 tanks & different configurations. Here is our boat's (N5025) specific schematic overview of the Freshwater System.
The 3 freshwater tanks are constructed of reinforced fiber glass & when full of fresh water, hold a combined capacity of about 325 gallons. The forward tank (~100 gallons) is mounted below the kids Bunk-rooms up front, the mid tank (~150 gallons) is located below the master stateroom sole, and the aft tank (~75 gallons) is located below the main engine. Each tank is equipped with a top mounted inspection plate. Access to the inspection plate is available by a removable hatch cover located in each stateroom and the engine room. The tanks are finished in blue gel coat to distinguish them from the red diesel fuel tanks (4 diesel tanks). The inspection plate is made of stainless steel and bolted to the tank for easy removal. Each plate is equipped with separate connections and hoses for supplying water to the fresh water pump, venting to the outside, remote tank level indication, and a dipstick. The top of each tank also has a fill line from a deck connection. The supply lines from each tank are routed to a manifold in the engine room equipped with isolation valves for each tank. A single line from the manifold is routed to the fresh water pump inlet connection. Standpipes are provided inside each tank for the fresh water pump suction line and the level indication sensing line and extend to within an inch from the bottom of the tank.
The freshwater pumps aboard Ophelia have been Jabsco or West Marine shureflo 12V pumps, or something similar. Basically we had relatively cheap and disposable pumps. However we also had average water pressure at times and the pumps tend to not last that long.
We decided to replace the primary freshwater pump with a Headhunter X-Caliber pump. This is an expensive pump. Time will tell if we like it better than the pump we pulled out, but I have heard great things about them. In order to install the pump, we needed to have our electronics installer run much heavier gauge wiring (30 Feet of 2 Gauge), to allow for the significantly higher amp draw. Once the new wiring was in place, we installed the new X-Caliber pump. I flipped on the 12V breaker and went through the process of bleeding the new pump and getting it on-line. As the moment of truth arrived....we quickly found that we still had crappy pressure. The pump was fine but we definitely needed to trouble shoot for airlocks and get to the bottom of the other problems.
As luck would have it, this new higher pressure pump shined a nice bright light on a very small, hair-line crack on the pre-filter strainer (pump protection strainer) to the secondary water pump, that we had not seen before. With both the new pump and the backup pumps on, as the water pressure in the water line would build up, the backup pump's strainer was visibly leaking and dripping a fair amount of water. I removed the broken strainer and ran a new 4 foot section of 1 inch OD (3/4 Inch ID) hosing from the backup pump to the T-Connector and everything worked. One last item to test was the ability to draw from all three tanks, with no airlocks, which for the first time in our ownership, we could do. So we finally are able to draw from all three tanks which increased our effective tank size from 150 to 325 gallons! Happy Ophelia!
Here is the spec sheet on the Headhunter X-Caliber freshwater pump: