Calorifier overflow pipe?/batteries

[BeninReading]

Afternoon all - I hope everyone is well.....

 

Two things - I have a pipe which leads into my bilge tank by the engine - I presume it is the calorifier overflow pipe - but when running the engine it dribbles - only a bit - but enough to warrant putting a bucket underneath. Is my assumption correct and is the fact that it is dribbling anything to be concerned about??

 

Secondly, I have topped up the batteries I can with DI water but some are sealed - can I assume that those without screw off caps are sealed and cant be filled up???

 

Thanks to anyone for a reply,

 

Big love, Ben

[bottle]

Secondly, I have topped up the batteries I can with DI water but some are sealed - can I assume that those without screw off caps are sealed and cant be filled up???

 

Probably, some batteries do not have individual caps, there may be a 'strip' of removable cap through the middle of the battery top.

[KenK]

Afternoon all - I hope everyone is well.....

 

Two things - I have a pipe which leads into my bilge tank by the engine - I presume it is the calorifier overflow pipe - but when running the engine it dribbles - only a bit - but enough to warrant putting a bucket underneath. Is my assumption correct and is the fact that it is dribbling anything to be concerned about??

 

Secondly, I have topped up the batteries I can with DI water but some are sealed - can I assume that those without screw off caps are sealed and cant be filled up???

 

Thanks to anyone for a reply,

 

Big love, Ben

 

Hi Ben,

If its from the calorifier it is normally fed to the outside world. The calorifier should have a pressure relief valve and temperature control valve on it, if it's dripping when the engines running and therefore heating the water, then the valve may need cleaning or possibly just adjusting. Trace the pipe and see where it goes and you should see the valves, they are normally marked.

 

Batteries which don't have screw off caps are indeed sealed and can't be topped up. Not Gell or AGM are they? Also while I think about it even wet sealed batteries should not be charged above 14.4V whilst non-sealed can be charged up to 14.8V, might be worth checking out your charging system.

 

Ken

Edited March 3, 2008 by KenK

[Keeping Up]

Hi Ben,

If its from the calorifier it is normally fed to the outside world. The calorifier should have a pressure relief valve and temperature control valve on it, if it's dripping when the engines running and therefore heating the water, then the valve may need cleaning or possibly just adjusting. Trace the pipe and see where it goes and you should see the valves, they are normally marked.

Or it may be nothing more than a sign that the pressure-relief valve is doing its job. It's quite common for them to dribble in this way, if the system setup doesn't include a suitably-positioned accumulator.

[chris w]

I agree with Allan. Once the water gets hot, it expands by about 4%. This water has to go somewhere and it therefore dribbles out of the pressure valve. It shows your pressure valve is working correctly. It's appalling that the boat builder/installer allowed this to just dribble into the bilges - it should be routed outside through a skin fitting.

 

Fit a 5 litre accumulator (for a standard 60 litre calorifier) tee'd into the hot water outlet on the calorifier. This can be done in 10minutes using push fit plastic piping and the dribbling will stop. Why dribble away the water you've heated? Cost for the accumulator, including a saddle clamp, will be around £35. (search ebay: make sure it's designed for hot water)

 

For any other size calorifier, the minimum size of accumulator will be 4% x (calorifier capacity) x 2; hence 5L accumulator for a 60 litre tank. Choose one to just exceed the minimum size.

 

Chris

[gralyn]

Usually a couple of twists of the knob on the pressure relief valve stops it dribbling. This is recommended anyway, every so often as it makes sure that it is not stuck.

[chris w]

Usually a couple of twists of the knob on the pressure relief valve stops it dribbling. This is recommended anyway, every so often as it makes sure that it is not stuck.

 

Did you not read my post above? The PRV will always dribble (without an accumulator fitted) when the water is hot.... otherwise your calorifier will explode when the water expands by 4%. If the engine has heated the water, you have no accumulator and the PRV stops dribbling.......... run.

 

Chris

 

PS: your advice about giving it a twist now and again is good though to ensure it doesn't stick

Edited March 3, 2008 by chris w

[ChrisPy]

Fit a 5 litre accumulator (for a standard 60 litre calorifier) tee'd into the hot water outlet on the calorifier. This can be done in 10minutes using push fit plastic piping and the dribbling will stop. Why dribble away the water you've heated? Cost for the accumulator, including a saddle clamp, will be around £35. (search ebay: make sure it's designed for hot water)

it doesn't have to be on the hot water outlet.

I have a check valve on the cold water inlet to the calorifier and an accumulator fitted between the check valve and the inlet connection.

[smileypete]

it doesn't have to be on the hot water outlet.

I have a check valve on the cold water inlet to the calorifier and an accumulator fitted between the check valve and the inlet connection.

 

Some calorifier manufacturers put the PRV on the cold side too, eg:

 

http://www.ecs-marine-equipment.co.uk/pdfs...nstructions.pdf

 

I'd expect it will last longer and be less likely to scale up in this way.

 

Though I'd defer to the instructions that came with the calorifier.

 

cheers,

Pete.

[chris w]

it doesn't have to be on the hot water outlet.

I have a check valve on the cold water inlet to the calorifier and an accumulator fitted between the check valve and the inlet connection.

 

Quite right. Thanks for adding that.

 

Chris

[Keeping Up]

it doesn't have to be on the hot water outlet.

I have a check valve on the cold water inlet to the calorifier and an accumulator fitted between the check valve and the inlet connection.

And another alternative (which I have) is that the non-return valve is in the hot water outlet from the calorifier, after the PRV, so the expansion is taken up by the cold-water accumulator tank (and before anyone asks, as has been asked many times including on this forum, no I have never known an occasion where any hot or even warm water has expanded back to the nearest cold tap)

[chris w]

The NRV's being sited in the cold feed is not just to stop warm water getting back to the cold tap. It's also to help obviate the possibility of any mixing of hot and cold which could lead to potential bacterial growth.

 

Chris

[smileypete]

And another alternative (which I have) is that the non-return valve is in the hot water outlet from the calorifier, after the PRV, so the expansion is taken up by the cold-water accumulator tank (and before anyone asks, as has been asked many times including on this forum, no I have never known an occasion where any hot or even warm water has expanded back to the nearest cold tap)

 

There's usually a gap between the calorifier coil/immersion element and the bottom of the tank, so it takes some time before the tank is heated right to the very bottom.

 

Even if there wasn't the water would soon cool as it expanded back along the cold inlet pipe.

 

cheers,

Pete.

Edited March 3, 2008 by smileypete

[chris w]

Even if there wasn't the water would soon cool as it expanded back along the cold inlet pipe.

 

cheers,

Pete.

 

That's my point, it cools to the temperature point at which bacteria can thrive. The NRV in the cold feed stops this mixing.

 

Chris

[Keeping Up]

The NRV's being sited in the cold feed is not just to stop warm water getting back to the cold tap. It's also to help obviate the possibility of any mixing of hot and cold which could lead to potential bacterial growth.

I am utterly convinced that this is just another one of those urban myths. Every hot water feed cools down through warm to cold, and would lead to such growth if it were a problem. I have never heard of any instance where such a problem has actually been encountered for this reason.

[chris w]

You may be correct Allan but, even if there's an outside chance of contamination, would it not be better to put it in the cold feed. Is there some other advantage to putting it in the hot outflow pipe?

 

Chris

[Keeping Up]

Well it works perfectly well there, and obviates the need for a second accumulator tank, which is reason enough for me

[smileypete]

I am utterly convinced that this is just another one of those urban myths. Every hot water feed cools down through warm to cold, and would lead to such growth if it were a problem. I have never heard of any instance where such a problem has actually been encountered for this reason.

 

Agreed.

 

The minute theoretical risk from Legionella in domestic plumbing, involves inhaling contaminated water in the form of an aerosol (ie when showering), but there is no risk to drinking the water.

 

cheers,

Pete.

Edited March 3, 2008 by smileypete