Calorifier Knackered?

[alisdair4]

I pose this question with a certain degree of trepidation, because I think that I know what the answer is going to be! Last Autumn, I drained down my pressurised-water system to the best of my (limited!) ability. That is, I opened both the hot and cold taps, and ran the pump until all I got out was air.

This week, having sorted out the (indirect-cooled, 20BHP Beta) new engine which should heat the water in the calorifier, I find that there is a leak in the damned thing. When the water pump is on, ie, the system is under pressure, this is a constant flow out of the calorifier (perhaps 1 pint in 2-3 minutes). When the sytstem is not under pressure (ie, water pump NOT turned on) there is a steady , and decreasing drip (maybe, 2-3 drops per minute).

Exam question. The leak appears to be around where the immersion heater joins the body of the calorifier. Does this mean that the whole thing is knackered? Given that the situation is manageable, I am loth to dismantle the galley at this stage in the season. But, should I be planning on a new Calorifier for the winter? More importantly, what must I do to avoid this happening again - the winters in Kiel are pretty frisky (-10-15!).

 

[vyv_cox]

It froze last winter. Running the pump with the hot tap open does not drain the calorifier because the discharge is at its top. You simply bubble air through the water. The only way to drain it is from the bottom, for which a tap is normally provided.

 

[Cloven]

It froze last winter. Running the pump with the hot tap open does not drain the calorifier because the discharge is at its top. You simply bubble air through the water. The only way to drain it is from the bottom, for which a tap is normally provided.

Have to agree.

Mine does not have a tap and I have to disconnect the cold water input in order to drain the system. Fortunately I was warned of this and did not have to find out the hard way!!

 

[Hoolie]

It sounds as if the damage is on an uninsulated area which will be accessible for repair. You might be able to get it brazed, more common on the continent than the UK.
Obviously it'll have to taken out, though that may not be too difficult depending how/where it's installed.

 

[Quandary]

As long as it is not Isotemp, (shiny s. steel casing) but even one of those may be repairable, there is a removable end plate with a rubber gasket under the cover. It took me a couple of goes with replacement gaskets but it has held for 2 years now (all fingers crossed)
If it is an Isotemp PM me and I will relate the details.

 

[Dockhead]

I had a similar problem with mine.

I always sail all winter and never drain mine. There have been some hard frosts but never a problem as the boat stays in the water. Then a few weeks ago, my calorifier started to leak at the seam joining the two copper hemispheres Odd that I got through the whole winter and then this appeared just in the spring, and no other signs of frost damage anywhere.

I tried to patch it with plumber's epoxy putty. It would work for a day, but the putty would not withstand the thermal expansion and would crack at the seam.

I tried to replace it, but the new calorifier I ordered didn't fit into the very specifically shaped space I have for it.

Finally I took it out and took it to -- a radiator repair shop. They brazed or soldered the leaky part of the seam. Then they pressure tested it, the way they would do a leaky radiator. Reinstalled and now working fine for the third day.

I think the copper ones are reasonably repairable, with the caveat that if they corrode or deterioriate inside where the various pipes are, maybe not. But if it's a simple freeze problem, maybe so.

The insulation is not a problem -- just strip it off. Replace it with foam from a can, and put that shiny insulation tape over the repaired foam.

The hardest part for me was getting the d*mned thing in and out. Mine lives under the salon sole, and a beam had to be removed to get at it. Then a whole bunch of pipe connections -- my first and not entirely happy encounter with plastic 15mm push-on plumbing.

 

[Modulation]

It froze last winter. Running the pump with the hot tap open does not drain the calorifier because the discharge is at its top. You simply bubble air through the water. The only way to drain it is from the bottom, for which a tap is normally provided.

+2. I had a similar issue 2 winters ago when I had to leave the boat in Belgium over the winter. I normally have heating on board so no need to drain down but was on a berth with no electricity. By the time I'd thought through the implications we were having temperatures of -5 or 6C. Fortunately I got to the boat and drained the domestic water thro the hot tap. Quite by chance I spotted the drain right at the bottom of the calorifier. An extra 60 litres came out through that. Result was we saved it from splitting.
If you are sure that your only damage is around the immersion boss you should be able to get a replacement brazed in. I would try to avoid the replacement option as the plumbing junctions will all be in different places and the job will just grow. Also the water pressure is comparatively low.

 

[Momac]

Are you sure it is the tank that is leaking and not the immersion heater or its gasket?