fresh water tank leak/emptying..Moody Eclipse 33

[golfclub]

Moody Eclipse 33,1989, fresh water leakage from blow-off valve at calorifier...tank empties in,say,12 hours..fresh water pump Par Max 3..hot water on 'shore power' not as hot as before problem..pump still runs on after shutting tap,so has to be switched off at main board...cold water 'pulses' at cold tap (do I need some sort of 'header tank ' ??...)....do I fit some alternative,remote,pressure switch to fresh water pump ?......I have seen some sort of reference to Cleghorn Waring....any ideas ??

Very many thanks,Scott.

 

[charles_reed]

You've a leak in the system (and probably a full bilge).

Just trace the leak and rectify that.

From memory the Par-max has a pressure tank already fitted, as part of the pump assembly.

 

[MarkJohnson12345]

I have a similar problem, though not as severe.

The pressure relief valve drips when the calorifier heats up. At first I thought that the problem might stem from the fact that our water bages were half full of air, which pressurised the system.

But having sorted that out, it still drips about half a bucket full in 12 hours of motoring.

I now think there might be a bit of air above the pressure relief valve outlet, which is not quite at the top of the tank. I will have to bleed the calorifier via the outlet pipe I think. Though I see no reason why this air if there is any does not come out via the taps.

There was a thread here very recently on the subject.

Regards

 

[jerryat]

Slightly off-thread (for which apologies) but can anyone tell me what pressure my calorifiers pressure relief valve should be?

It tends to weep a few drops (max about three tablespoons full on a long trip) and I know it's not leaking hoses 'cos I've checked the whole system thoroughly. The only other source 'available' seems to be the relief valve.

The system's on a Fulmar and has two outlets (galley and heads) and I reckon the calorifier is about 6 gallon capacity. It is pressurised via a PAR belt driven diaphram pump (32950) with it's own pressure switch as normal.

I can get to the relief valve ok and want to change it at the end of the season during the lay-up.

Grateful for any help.

 

[MarkJohnson12345]

Mine is 3 bar.

Regards

 

[Anchorite]

Re: Hot water tank leak/emptying

Pressure pumps on boats are usually about 2 bars (30 psi); calorifiers usually have a 3 bar relief valve. Water expands about 3% when heated say 60° C. As water is uncompressible the expansion can take 2 routes: either the flexible pipes often used on boats will expand and absorb some or all of the 3%, or the pressure will increase and the relief valve does its job. If your valve is fitted on the top of the tank you may get a deposit on the seating which in time will lead to a leak: to cure, depressurise the system, remove the valve and treat it as for descaling. Calcium deposits are (a bit) less if the PRV is at the bottom, water 'loss' is the same.

 

[nedmin]

I have got a flexible pipe from outlet of pressure relief valve and then led out the engine room breather vent.Have you checked your pressure relief switch,you can usually get them off.push with a pencil or similar and see if you can hear the micro switch operating ,or put a meter across.why if all seems ok why not try adjusting the pressure down ie turn to take pressure off the spring,but count the number of turns so that you can put back to original setting if needs be.Dont know about parmax but you should have an accumalator somewhere in the system,they are usually a pressure tank with a bladder or ball to stabilise the pressure.you should get about a cup full of water out the pressure relief valve everytime you warm up the engine.

 

[jerryat]

Thanks Mark and Anchorite,

My calorifier's about as standard as they get so will look for around 3 bar if necessary. Darned good idea to try cleaning first though, so thanks Anchorite for that, I give it a go before replacing it. /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

Cheers jerry