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Calorifier sprung a leak


jetzi

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I have a 53 litre twin coil calorifier. I don't know how old it is but my boat is 20 years old.

 

I was cleaning my back room when I noticed a trickle of water running down the outside of my calorifier. The source seemed to be the outlet hole in the top, but all the connections appeared to be tight. When I pressed on the jacket more water bubbled out. I decided to remove the jacket to see if I could find the source of the leak and this is what I found:

 

IMG_20191116_123210.jpg.131f1a040ad5f040bf5123501f041587.jpgIMG_20191116_123145.jpg.2e78a6a200e5316ba3222c82bf41f93f.jpgIMG_20191116_123127.jpg.c48f58d599b03445ec71c49203d0a8cc.jpg

 

It looks to me to be a puncture at the seam on the top. Unfortunately I have quite a bit of water in my bilge now and my floor is swollen.

 

Can a puncture like this be braised or re-sealed? Or if this is just a sign of age will another puncture spring up elsewhere?

 

If I need to buy a whole new cauliflower, does anyone have any recommendations? I'm planning on calling the number on the jacket on Monday - perhaps they will have a suggestion for me.

 

Edited by ivan&alice
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I’d say it is a sign of a missing ir non-functioning accumulator. 
 

Soldering it over will be easy given the good access. Brazing would be better. 
 

Did you notice the water pump operating periodically when you havent used a tap? 
 

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1 minute ago, Mike the Boilerman said:

 

Same thing. The two terms are interchangeable.

 

 

I would say physically they are the same, but once pressurised they become different in that they function differently.  An expansion vessel set to a slightly higher pressure than pump cut off can not function as an accumulator, likewise an accumulator set to a much lower pressure will have very little capacity to act as an expansion vessel.

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We have recently replaced our cauliflower and installed an extension tank on the hot side. When the hot water is run we gethigh water pressure until the pump kicks in. Then after urging tap off he domestic water pump runs for approximately and up to 20 seconds.

 

Is this because there's too much pressure in the hot side of the system? Can I let out some pressure to regulate?

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7 hours ago, Chewbacka said:

I would say physically they are the same, but once pressurised they become different in that they function differently.  An expansion vessel set to a slightly higher pressure than pump cut off can not function as an accumulator, likewise an accumulator set to a much lower pressure will have very little capacity to act as an expansion vessel.

 

Exactly, and if we use the correct terms it tends to reduce any confusion amongst those who are less familiar with boat plumbing systems.

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Brazing would be a bit risky because of the higher temperatures. You could end up with a much bigger hole. Quite common practice when a pipe has been punctured by a screw/nail/drill etc. is to get a copper clout nail from a roofer, stick it in the hole and solder around it. 

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I know that it is £300 (ish) to replace but having 'gone' once it may well 'go' somewhere else. You didn't find it this time (just by luck) and have now got water stained woodwork and bilges full of water. Next time could be worse.

 

I'd 'shake the moths out of the wallet' and replace it - at least you will have confidence in it.

 

The alternative of soldering a nail in the hole would leave me with sleepless nights.

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1 hour ago, Mike the Boilerman said:

I’d say it is a sign of a missing ir non-functioning accumulator. ,
 

Soldering it over will be easy given the good access. Brazing would be better. 
 

Did you notice the water pump operating periodically when you havent used a tap?

No I have not noticed the water pump operating. There is an accumulator fitted just after the fresh water pump and before the cold feed to the tank (and cold taps). Can the accumulator break? Do you think there is likely to be a "cause" rather than just failure from several years of expansion and contraction?

 

1 hour ago, Boater Sam said:

Solder it up but check your PRV is not over 2.5bar before it vents. Best is to put a brass screw in the hole and solder it all together.

Modern stainless steel calorifiers are probably more reliable.

Where would I find the PRV - Pressure Reducing Valve? There is an relief valve about 2/3 of the way up which vents the tank to a skin fitting, but I don't see any valve or expansion tank on the hot outlet side of the calorifier (which leaves the tank right at the top).

 


I'll buy a blowtorch, solder and flux tomorrow and give it a bash. I don't think driving a copper nail into it would be helpful. The hole is so tiny - the spray is almost a vapour - and being that it is on the seam I'm concerned the nail would cause it to split. Please let me know if you think this is a crucial step.

 

47 minutes ago, mrsmelly said:

Bin and replace. 

 

5 minutes ago, Alan de Enfield said:

I'd 'shake the moths out of the wallet' and replace it - at least you will have confidence in it.

I'll look at replacing it as well. I have a larger plan (mentioned before) to incorporate a second solid fuel stove, back boiler and gravity-fed heating. To do this I gather I'll have to raise the calorifier. When I do this I will put a tray with a drain leading to a skin fitting, which will just give me a little more confidence knowing that if my tank leaks it will end up in the cut rather.

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Maximum working pressure of only 2.5 bar seems on the low side to me.

Many pumps are capable of pressurising to more than that.

If you put a 2.5 bar PRV on it, that's at the absolute limit it is certified for, so the pump could have a maximum working pressure of no more than 2 bar.

Maximum working pressure of only 2.5 bar seems on the low side to me.

Many pumps are capable of pressurising to more than that.

If you put a 2.5 bar PRV on it, that's at the absolute limit it is certified for, so the pump could have a maximum working pressure of no more than 2 bar.

If replacing look for something certified to more like 4 bar, which will allow a 3 bar PSV, and some safety margin so as to not over pressurise the tank.

5 minutes ago, ivan&alice said:

I'll look at replacing it as well. I have a larger plan (mentioned before) to incorporate a second solid fuel stove, back boiler and gravity-fed heating. To do this I gather I'll have to raise the calorifier. When I do this I will put a tray with a drain leading to a skin fitting, which will just give me a little more confidence knowing that if my tank leaks it will end up in the cut rather.

If you want to heat a calorifier on gravity alone you really need to have one with a large bore coil and connections.

Most narrowboat calorifiers are limited to 1/2" bore coils, and probably not that efficient without a pumped circuit.  I got one made with a larger bore coli, but expect to pay a lot more than the £300 number someone mentioned above.

Edited by alan_fincher
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Check the pressure but it is time for a new calorifier. Avoid all the hassle of another leak in the future, at 20 years old it is probably corroded and prone to leaking again. 

 

If you really want to save money and live with it short term, then when the tank is drained to repair, try and inspect the inside and get an idea of the possible corrosion. USB intrascope cameras are cheap these days.

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59 minutes ago, ivan&alice said:

 

I'll buy a blowtorch, solder and flux tomorrow and give it a bash. I don't think driving a copper nail into it would be helpful. The hole is so tiny - the spray is almost a vapour - and being that it is on the seam I'm concerned the nail would cause it to split. Please let me know if you think this is a crucial step.

Not sure that it's crucial. If it was mine I would do it but then I do have copper nails in my van. I wouldn't hammer it in, rather drill out the hole so it was a tight fit. The advantage is that it gives you something to hold the solder in place and provides a strong cap. You can tap the head of the nail to the contours of tank and let the solder run in through capillary action.

 

Trying to get solder to stick on its own is quite tricky, as this, erm 'expert' proves:

 

 

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1 hour ago, alan_fincher said:

If you put a 2.5 bar PRV on it, that's at the absolute limit it is certified for, so the pump could have a maximum working pressure of no more than 2 bar.


If replacing look for something certified to more like 4 bar, which will allow a 3 bar PSV, and some safety margin so as to not over pressurise the tank.

If you want to heat a calorifier on gravity alone you really need to have one with a large bore coil and connections.

Most narrowboat calorifiers are limited to 1/2" bore coils, and probably not that efficient without a pumped circuit.  I got one made with a larger bore coli, but expect to pay a lot more than the £300 number someone mentioned above.

Interesting that you'd need a larger bore coil - the main reason for a gravity feed was to save on electricity, noise and complexity of having a pumped system. But if it's going to be that much hassle, then I may as well stick with the pump.

 

300 GBP was about right to replace this calorifier as-is ? oh well, at least it is the kick up the pants I need to fix my central heating.

 

In addition the engine and Eberspaecher that I currently heat water with, I'm planning on adding a back boiler and solar-powered immersion heating (to use up the excess power in summer). My Eberspaecher/radiator circuit sprung a leak a few months back and I haven't got around to fixing it...

 

 

13 minutes ago, stegra said:

Not sure that it's crucial. If it was mine I would do it but then I do have copper nails in my van. I wouldn't hammer it in, rather drill out the hole so it was a tight fit. The advantage is that it gives you something to hold the solder in place and provides a strong cap. You can tap the head of the nail to the contours of tank and let the solder run in through capillary action.

 

Trying to get solder to stick on its own is quite tricky, as this, erm 'expert' proves:

How silly of me, of course you would drill the hole for the nail. For some reason I pictured banging a nail into the seam. I'll see if I can organise one lonely nail - Screwfix only sells a kilo bag!

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9 minutes ago, ivan&alice said:

Interesting that you'd need a larger bore coil - the main reason for a gravity feed was to save on electricity, noise and complexity of having a pumped system. But if it's going to be that much hassle, then I may as well stick with the pump.

 

300 GBP was about right to replace this calorifier as-is ? oh well, at least it is the kick up the pants I need to fix my central heating.

 

In addition the engine and Eberspaecher that I currently heat water with, I'm planning on adding a back boiler and solar-powered immersion heating (to use up the excess power in summer). My Eberspaecher/radiator circuit sprung a leak a few months back and I haven't got around to fixing it...

 

 

How silly of me, of course you would drill the hole for the nail. For some reason I pictured banging a nail into the seam. I'll see if I can organise one lonely nail - Screwfix only sells a kilo bag!

If the faliure is on a seam i doubt that putting a nail in will help, and most likely would just open up a bigger gap. Likewise, you may find any solder repair will end up moving the problem along the seam. You have nothing to lose by trying but keep the heat moving.

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3 minutes ago, BWM said:

If the faliure is on a seam i doubt that putting a nail in will help, and most likely would just open up a bigger gap. Likewise, you may find any solder repair will end up moving the problem along the seam. You have nothing to lose by trying but keep the heat moving.

Yeah, I'm going to try, but I don't have high hopes. Otherwise I just have to shell out for a new calorifier. My big concern is whether there is something with the system layout that could have caused this other than just age. I don't have any PRVs or NRVs or expansion tanks, the only thing I have is a accumulator tank on the cold water side.

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3 minutes ago, ivan&alice said:

Yeah, I'm going to try, but I don't have high hopes. Otherwise I just have to shell out for a new calorifier. My big concern is whether there is something with the system layout that could have caused this other than just age. I don't have any PRVs or NRVs or expansion tanks, the only thing I have is a accumulator tank on the cold water side.

If you genuinely don't have a PRV then that's almost certainly an issue!

Some NRVs are far from obvious, as well, and can be hidden within something that doesn't look like it contains one.

EDIT:

Except that it sounds like despite what I have quoted you do have a PRV...
 

Quote

Where would I find the PRV - Pressure Reducing Valve? There is an relief valve about 2/3 of the way up which vents the tank to a skin fitting, but I don't see any valve or expansion tank on the hot outlet side of the calorifier (which leaves the tank right at the top).


Can you post a picture of what you have.

Edited by alan_fincher
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