Fresh water leak on MH40

[Phantom154]

I recently took possession of a 2014 MH40. It has developed a leak in the fresh water system. It started slowly: pump coming on every couple hours. Today it started coming on every few minutes. I have looked everywhere I know there are pipes: under galley and head sinks, water heater, cockpit shower; and I can't find any water or wet surfaces. Are there any specific places that are subject to leaks. We have been using the aft shower and I can't see under the surface where the shower control handle is located. So it could be there.

 

[richk]

I have a MH37 and haven't had the problem you note. I suggest you PM MH40 owners via this site.
Rich

 

[Jackdaw]

The under-pressure water could be leaking backward through the pump to the tank side, triggering it to come back on.

 

[Terry Cox]

Our system was doing the same thing awhile ago and it turned out to be the water pump check valve. Purchased a new pump and check valve. Replaced the valve in the old pump and will keep it as a spare. System runs great with the new pump.

 

[Phantom154]

Thanks for the input. When I turned the pump on this morning, it didn't come on by itself all day, so no leak. I filled the water tanks late this afternoon (we are at a marina right now) and it started leaking again. I hate those intermittent problems. Sometimes a complete failure is easier to work with.

 

[Terry Cox]

The new pump that we purchased (link below) was the same model as the 1991 original. Our symptom was when on and under pressure with no draw, it would do a short burp cycle about every ten seconds. When I called the manufacturer and explained the symptom, the check valve was the likely culprit.

When we purchased the boat in 2002 it was doing it then, but that was partly because of a small hot water fitting leak that fed the sit tub faucet and in an impossible location. Took care of that, but short burp cycle continued, but less frequent. Now all is well and the was two years ago.

http://www.defender.com/product3.jsp?path=-1|51|2234226|2234231&id=151050

Here is another link that describes our incident in more detail, which may be of some help.

http://hunter.sailboatowners.com/mods.php?task=article&mid=45&aid=8246&mn=42

 

[HMT2]

I had a similar problem on my H31. I spent hours and hours looking for a leak. Never found it, replaced the pump, that fixed it for a month, then the same intermittent running of the pump. Since it was under warranty, after several discussions with various WM staff, I replaced it again...same problem. Then I finally RTFM and discovered that what I thought was one of five screws holding the pump together was actually a pressure adjustment valve. While it was running (the intermittent running not on because the water is on) I adjusted the pressure adjustment screw until it stopped. It hasn't happened again in three years. The pump is a Jabsco Aquaking 3.0 GPM pump.