Can't find the fresh water leak ...

[HOB No1]

On a 2008 H36, have a fresh water leak. The water is running to the bilge from under the fuel tank (it is fresh water, not diesel). Suspect it is from one of the lines from the manifold to the cockpit shower locker. However, when both the hot and cold valves on the manifold for the cockpit shower are closed, the leak still happens. (All valves on the manifold are closed, and the leak is still occurring.) With the valves closed and the water pump on, the pump is trying to build pressure, but continues to run as the water is escaping somewhere.

Background info, winterized the system by blowing air through the lines. Thought all the water was out, but maybe there was some left in the low spot in one of the lines that froze, cracked and maybe the source of the leak. Just can't see any water around the lines that are visible (which is only a small part).

A couple of questions:
- Why does the leak still occur when the manifold valve is closed? The only lines that do not seem to go through the manifold are the hot and cold to the shower. And those lines are not close to where the water from the leak appears.
- Is there another water line that could be the culprit? One not going through the manifold.
- Has anyone replaced the lines to the cockpit shower? Any advice/warnings/tips/etc?

TIA
Doug

 

[sailcapt340]

When you can, post some photos of what you can see. Let us know what connector fittings you have as well.
I ask because I have John Guest Fittings on my 340. And each year I have at least one of these connections loosen due to lack of water pressure in the lines. Which leads to a dripping when fill the water tank and send water through the system. It doesn’t happen during the summer as we use the water, but after the winter layover it does in one or two.
It could be I am doing it, when I loosen one when I change over my bypass line to refill the water heater. Its cramped in there so that’s entirely possible, but not every year.
If you blew out your lines well, you should not have that much water left in a line the could freeze. There should be plenty of room for expansion along the entire line.
Just my thoughts, but I actively check each connector by making sure I feel and hear the click when the lines are inserted.
Let us see what you have for connections and start the help you need.
This is what I have:

 

[American_Mainsail]

Another question: When the valves are open (try it closed too), does the fresh water pump recharge pressure every few(ish) minutes, or does it hold pressure indefinitely until a faucet is opened?

 

[artboas]

Little late now, but I find that using antifreeze is much safer than blowing out lines. There are low spots that can come back to haunt you.
Check your HW tank area for the leak problems
To track down mystery bilge leaks, there are 2 methods
Food dye, and talcum powder .
Food dye in a bilge will show you which direction leaks are coming from.
As well, sprinkling around talcum powder gives you a good idea.
As far as your pump cycling, this could be a leaky check valve in the pump.
If you want a quick and easy way to locate the leak however,, ,,

disconnect the pump intake.
Connect another short length of hose to the pump intake
Put the free end into a container that has water with food colouring. You will know the answer in minutes .

 

[Crazy Dave Condon]

Much was written on the Hunter 36 by Jim Seaman and his boat was called JAVA. Not sure if that topic was covered about the lines. Jim is deceased

 

[HOB No1]

Thanks for the responses. And my reply:
- Sea Tec/Aqua Lock fittings. No leaks from any that are visible (don't know of any that aren't, but wouldn't be the first surprise ...)
- With all the valves on the manifold closed, the pump runs continuously, at a lower than normal pressure. Water appears to be going somewhere.
- Can't get talcum powder near the source. It appears from underneath the fuel tank (aft of the manifold and heater), so know direction where it's headed.
- Assume the only plumbing are the lines to the cockpit shower. But the valves are closed!
- Like the idea of food dye (hear it might leave a stain?), especially with the manifold closed.
- One area not investigated, the fresh water electric toilet. Not sure where it would be getting water if the switch that fills the bowl is off. But will take a closer look.
Will provide updates. Thanks again.

 

[twalker H260]

Check the lines between the tanks and the pump. If the pump is sucking air it will continue to run, but won’t be able to pressurize the system. The water leak will be slower than it would be on the pressure side - and likely dependent on the water level in the tanks - fuller the tank the greater the leak volume. On our boat there was only a few whale type connections between the pump and the single tank so it was relatively easy to locate the offending connection.

 

[Banooma]

I've recently been working on a manifold leak found on my 05 H36 during spring commissioning, so my examination of my boat's plumbint is pretty fresh. On mine the cold water line to the hot water tank bypasses the manifold. My hot water tank is located to starboard, under the aft berth, not far from the fuel tank. Maybe your cold or hot line at the hot tank aren't making a good seal and leaking from there?