Pressure relief valve on colorifier. Our hot water tank is dripping..

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rays

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water constantly into the overflow pipe. This drains into the bilge and results in v. annoying frequent bilge pump activity. Have tried turning the end (which opens the valve) but this doesn't fix the problem. Have read somewhere that the valve gets bunged up with calcium and needs to be taken out and soaked in limelight or similar. Has anyone tried this? What's the best stuff to use?

Thanks forum.
CD
 
Buy a new one from a plumbers - very cheap, from £2 - £7 depending on where you buy.

Make sure you get the same BAR rating. I had problems because I could not get 4.5Bar, my system seems to run at a higher pressure than most, - only 2.5, 3, 3.5 or 6 normally available from plumbing sources, - I located a 4 bar from Midland Chandlers - but £9 incl postage. - but very good service.
http://www.midlandchandlers.co.uk
 
Check the max pressure your calorifier is designed for - if you can see the label! Possibly 3.5bar. Your relief valve will then probably blow off at 3.0 bar.

A leak problem will arise if the peak pressure your water pump delivers (for instance) is 45psi, not an uncommon pressure. Which is just about 3 bar . . .

Yes, you can clean out the relief valves with acid, but it is possible that the real problem is slightly too high a delivery pressure from your pump, and a slightly low setting for the relief valve spring. So, check the specs first - easier said than done, I know.
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

Often crap gets under the valve seating and it doesn't close properly.

Try manually opening the valve and with a big slice of luck the offending rubbish will be washed away. If not, a new valve is the best solution.
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

Now had you been an Oxford man, you would have wondered if the valve is designed to flow a little water as the system heats up and the water contained expands. This avoids excess pressure in the system with possible consequences for the circulation pump valves. Or at least it does in my Moody where the overflow is fed stylishly into a cut off pop bottle - Moody themselves having routed the water into the (almost non existent) bilges.

Do you think you will win on Saturday? I was tempted to add a /forums/images/graemlins/laugh.gif but that's a bit of a hostage to fortune.
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

The pressure switch in my pump became partly clogged and needed greater pressure to switch the pump off, this kept blowing the calorifier safety valve. Cleaned the switch and everything was OK again.
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

Designed so that the system does not explode if over-pressurised, they leak water either because the system is over pressurising (overheating) or because there is some crude on the seal or, more usually, the internal spring weakens. They are not worth the effort attempting to clean them so, assuming you are sure the system is not overheating, maybe buy a new one?
 
It is perfectly normal for the pressure relief valve to pass water due to expansion,why not put a length of plastic pipe on the outlet and let it leak outside. Mine exits thro. the engine room vent.
 
I now when motoring turn off pump and open the hot tap. No more water in the bilge, even works with imersion on if you turn pump of and use pump to turn water on and off... just a tepery way to do it..regards all...
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

When I installed a Calorifier in my Moody, following a suggestion on the MOA site, I ran a tube from the prv to the down pipe of the nearest cockpit drain and , my own idea, I connected this using a washing machine waste drain fitting, which has a built in cutter- result simple installation & no water in the bilges (at least not from the Calorifier!)
 
Re: Pressure relief valve on colorifier. Our hot water tank is drippin

If this is a Cleghorn Waring unit - read the instruction label (if its still on there!)

You are supposed to rotate the relief valve by turning the knob ONCE a MONTH.

I found that out after I managed to end up with 70 gallons of water in my bilge as the relief valve blew off.

Simple few rotations allowed valve to open and get rid of foreign object.

Hasnt happened since I read the instructions, funnily enough /forums/images/graemlins/ooo.gif
 
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