My Calorifier is leaking :(

seamaster30

seamaster30

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andythilo said:
Here we go again! More bloody problems :D

My water pump wont switch off. Water pumps through taps fine, but turn off taps and pump keeps running.

So obviously there is a leak somewhere as the pressure in the piping isn't building up to shut off the pump. While the pump is running I hear running water from the side of the boat. I look over to see a jet of water shooting out the side of the boat :eek: :D.

So I trace the pipe and it runs back to the calorifier. Its the pipe that vents from the radiator cap if the pressure builds up to much. So I open the cap to have a look and in a comedy style I get soaked as the pressure in the calorifier shoots water over my face (good job I handn't had the engine running :D)

So the problem is the radiator cap, it clearly isn't sealing the tank and water is constantly leaking out through the pressure pipe. So I pop back to the Chandlery and buy a new cap. It looks deeper than the older one, but alas it's still leaking :( It's better than the old one but water is still leaking out and the pump still running.

So what can I do? fit more washers to the cap to try and seal it? Or is there a special calorifier cap that I need??

Help...... :)
Click to expand...

Don't mess with the washers - is the new cap for the right pressure? - if so it sounds like your pressure switch is not working.
 
Here we go again! More bloody problems :D

My water pump wont switch off. Water pumps through taps fine, but turn off taps and pump keeps running.

So obviously there is a leak somewhere as the pressure in the piping isn't building up to shut off the pump. While the pump is running I hear running water from the side of the boat. I look over to see a jet of water shooting out the side of the boat :eek: :D.

So I trace the pipe and it runs back to the calorifier. Its the pipe that vents from the radiator cap if the pressure builds up to much. So I open the cap to have a look and in a comedy style I get soaked as the pressure in the calorifier shoots water over my face (good job I handn't had the engine running :D)

So the problem is the radiator cap, it clearly isn't sealing the tank and water is constantly leaking out through the pressure pipe. So I pop back to the Chandlery and buy a new cap. It looks deeper than the older one, but alas it's still leaking :( It's better than the old one but water is still leaking out and the pump still running.

So what can I do? fit more washers to the cap to try and seal it? Or is there a special calorifier cap that I need??

Help...... :)
 
It sounds as if your coil inside the calorifier is leaking. You are then pumping your domestic water into the engine cooling system.
 
how the hell is post above mine?

Anyway, it's a brand new water pump just fitted today. I dont know if the cap is for the right pressure, thought it was a standard part? I don't think it's pressure problem anyway, simply that the cap isn't sealing the tank. There is no way that the cap is gonna be overcome by the pressure of a small water pump.
 
wtf is going on lol.

Anyway, no it's not a coil leak. It's the cap no sealing on the tank and therefore the water is going out of the pressure relief and out into the river.
 
OK if you are determined that it's not a leaking coil. But how else do you explain that your domestic water pump is pressurising your engine cooling system?
 
But how else do you explain that your domestic water pump is pressurising your engine cooling system?
Click to expand...
When he said "radiator cap" he meant the pressure cap on the calorifier not the pressure cap on the engine cooling system (assuming it has one)

Either the cap is the wrong type for the calorifier or the pressure rating is lower than the cut off pressure of the water pump!

What's the cut off pressure and what's the cap rated at?
 
Last edited:
Vic,
Yes, you're quite correct. When I saw "Radiator Cap", I thought he meant a radiator cap.

Andythilo
Radiator caps usually relieve at much lower pressures than the pressure relief valves normally fitted to calorifiers. You would need a cap set to relieve at a higher pressure than your pump supplies.
 
Are you sure the pressure switch on the pump is working?Why not remove pipe from water pump outlet not the end nearest to pump but the other end,Put a piece of round wood in the end and jubillee clip it to seal it,start pump and see if it cuts out.If it does it could be that the pressure switch is set too high , some pumps can be adjusted for pressure they have a small screw at the end near where the wires go in. Its possible the micro switch on the pressure switch is shorted if it doesnt trip out.
 
Ok so mu pumps cut off is 20psi which is 1.4kg/cm2. Radiator caps generally at the higher end are 1.3kg/cm2. I think I might just chuck the crappy old calorifier and fit a new one with a immersion heater.

Quick Q, do you have to fit an expansion tank with newer calorifiers?
 
andythilo said:
Ok so mu pumps cut off is 20psi which is 1.4kg/cm2. Radiator caps generally at the higher end are 1.3kg/cm2. I think I might just chuck the crappy old calorifier and fit a new one with a immersion heater.

Quick Q, do you have to fit an expansion tank with newer calorifiers?
Click to expand...

I shortened the spring on a new pump to reduce the cut out pressure as it was too high and caused the pressure release valve to leak like yours - but don't try it unless you are sure what you are doing.

An expansion tank is optional but gives a much more stable water supply and is easier on the pump as it doesn't keep cutting in and out.
 
What I dont get is new calorifiers generally have 4 bar pressure release valves, so my calorifier is obviously not built to cope with the pump i've bought.

So heres a thought, what if I took the hose off the overflow/pressure outlet and fitted an inline pressure relief valve (4 bar)? Would the calorifier cap take the pressure? Once the pressure reaches 20psi (1.4 bar) the pump would shut off anyway.

Thoughts??
 
andythilo said:
What I dont get is new calorifiers generally have 4 bar pressure release valves, so my calorifier is obviously not built to cope with the pump i've bought.

So heres a thought, what if I took the hose off the overflow/pressure outlet and fitted an inline pressure relief valve (4 bar)? Would the calorifier cap take the pressure? Once the pressure reaches 20psi (1.4 bar) the pump would shut off anyway.

Thoughts??
Click to expand...

Whatever pressure the tank ends up at when the pump cuts out, it will get higher as the water is heated up.
If you have seen what can happen to a hot water tank (on mythbusters http://www.youtube.com/watch?v=ekEHfihiNz4) I think you would agree that messing about with safety devices or trying to use it outside of design parameters is a dodgy path to tread. - OK - the video is a little extreme, but gives you some idea of what you are dealing with.
If you can't find out what pressure the tank is rated at or reduce the pump cut out pressure, you need to replace the tank to be safe.
Could you fit another in line pressure switch rated at a lower value until you need to replace the tank?
 
Well I could but it's more money, throwing good after bad. I'll just run using the switch until i've replaced the calorifier, unless I can find a replacement cap.
 
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