Fresh water being pumped overboard, whats wrong, how do I fix it?

C

cliffdale

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Fresh water pumps about every 15 seconds. First thought was frost got the pipes, but no water found in the bilges.

I eventually found the water coming out of a pipe tucked well under the swim platform. I think its something to do with the hot water tank since the pipe is on the same side as the calorifier.

The pipes are well hidden behind the port engine and I couldn't trace back the outlet.


Any ideas what the problem is and how to fix please?
CD
 
If it is to do with the calorifier it is probably the pressure relief pipe, Answer is to fit an expansion tank in the system to allow the hot water to expand when it heats up.
 
Is your domestic pump running all the time? it must be if the releif valve is stuck open, if not the problem is elswhere.
 
Its probably at one end of the calorifier tank.

Usually at the least accessible end /forums/images/graemlins/confused.gif
 
Have you confirmed you are actually loosing freshwater out of the tank?

I've found my freshwaterpump starting very often when its cold. First I thought it was a leak but concluded the water leaks back into the tank -> preassure falls and the pump starts.
I assume the rubber in the pump gets less flexible and dont manage to hold the pressure.
 
Definitely freshwater pumping out. When the domestic pump cuts in the flow speeds up then slows down slowly until the pump cuts in again.

If I didnt switch off the domestics, it would empyty the storage tank within a couple of hours.
 
Your domestic water pump will work on a pressure system, ie, whey the back pressure drops by opening the taps the pump operates when you close the taps the pump should stop operating. first check all pipes leading from the pump if those are okay then the problem will have to be inside your domestic water heater. But you said that thee water is going overboard.. HOW. water can only go overboard through either your sink overflow, your bilge pump or via your heating pipes from your engine and only if your engine is cooled by direct salt/fresh water from outside your boat. if you have a heat exchanger cooling your engine then the fresh water within your system would not escape.. I can only think that there is something you have omitted to tell us. If you have no water in the bilge it may be that the automatic bilge pump is getting rid of it. The only other thing is that the setting on your domestic pump is set wrong but that still wouldn't explain the disappearence of the water..
regards. Eric
 
This had been an occasional problem on Moody yachts. If there is debris in the PRV on the calorifier, it leaks and the fresh water pump cycles to replace it the lost water.

An expansion tank in the system helps reduce the pressure, but if the valve is faulty it will not help.

Solutions include an overflow bottle, or pumping the water overboard - which sounds like your situation. But replace the PRV first.
 
Ok,
If its the calorifier and you can get to it then you should be able to disconnect the pipe comming from the relif valve and see if water comes out. If its not this then maybe someone has drained the calorifier and forgot to shut the valve.

If its not the calorifier at all then maybe its the shower stuff on the swim platform.
 
As second thought. I had the same problem and found that a compression fitting was not pushed in far enough, it only dripped but was enough to kick in the pump. Most modern boats are fitted with plastic pipes with the modern type fittings, check all your fittings first. then go to the pressure relief valve on you water heater and adjust it down a little and see if the pump stops. Cold weather, in my experience, does not effect modern pumps unless the sea freezes in which case the air tempreture within the boat will also be freezing. This will, in turn freeze your fresh water system.
Eric
 
[ QUOTE ]
It's the domestic pump cutting in every 15 seconds. Any idea where to locate the relief valve?
Cd

[/ QUOTE ]


It is normally fitted to the calorier, if you can locate it, try turning the circular knob clockwise a couple of times, the seat of the valve is on a cam, so turning it will lift it clear and allow any small pieces of debris to flow clear, if you are lucky.
 
OK - I had this problem and it was rectified when I changed the PRV to the calorifier.

The T34 is fitted with an expansion vessel.

Sometimes when the PRV is checked/serviced a small amount of debris finds its way onto the seat. You can sometimes dislodge it by opening/closing the valve a few times (just rotate red knob you will feel when it seats again). If it only occurs when you get very hot water, I would check the HT Cut Out stat is working OK on top of the immersion cylinder. Or if the water pump is running continuously, I would check its pressure switch and the charge in the expansion vessel to make sure they are OK. But I reckon it is the PRV!

Some pictures showing location of these fittings as follows (the immersion heater has two stats under a cover on top of the cylinder - one sets HW temp and one is a high temp (overheat) cut out. Anyway images as follows, hope they help:

23022008198.jpg


You can see the shrada connector at the top of the vessel which is used to set the air charge pressure (or sometimes nitrogen is used):

03032008233.jpg


The blue stat sets the HW temp and the red is a high temperature cut-out with a manual reset button on top:

Picture050.jpg
 
Either the pressure relief valve spring weak, replace valve,

Or water pump pressure switch not turning pump until to much pressure,

If pump stays on the pressure relief valve lets off to stop bursting tank. Sounds like pressure switch and valve pressures are to close, could even be dirt in the switch.

I agree with John100156
 
Wow, thanks for the pictures!!!

Thats brilliant!

Im going down Boxing day to have a go. Its a tight squeeze between the engine and Hot water tank.

Im hoping opening and closing the valve will fix the problem.

Cheers
CD
 
Just to confirm that it is the valve that's faulty, why not heat the calorifier up, and check whether the pump is spewing warm / hot water out. Although I can't imagine what else it could be.
 
This sounds a bit familiar, I had to fit a new pressure switch on my domestic pump last year (old one froze & split) and thereafter had the same problem as you describe. I fitted a new PRV, though no improvement. I did consider the expansion vessel option. The problem was that pump output pressure was exceeding the PRV rating, I dont think theres much difference .

Following a long chat with Jabsco, problem was eventually solved by winding out the screw on the pump pressure switch by 1/2 turn - very quick & easy. If this is a similar thing I would try turning the PRV head a few times to clear any crud then maybe consider fitting a new one. If that doesnt work, suspect the pump pressure switch. good luck
 
Good point, I suppose one easy way to check this is to test the system pressure to see what it's reaching when the pump switches off! This could also be used to check the operation of the expansion vessel, etc. Buy a cheap water pressure gauge/fittings, remove the shower head of the transom/shower hose and fit the gauge, open valve! Or you could fit it permanently below using Hep2o tee, etc. Not sure what the PRV is set to, but at least you will have some empirical data to work with! Try re-seating the PRV first! Best of luck.
 
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