The origianal hot water cylinder (calorifier) appeared to be in good order despite its age. The cylinder was connected to the engine coolant system which heated the cyliner when the engine was running and there was also a 240 volt immersion heater which could be used for hot water when connected to the shore power. As it is our intention to spend time on the inland waterways, mains shore power will not always be available. However I always found that the electric immersion heater took a very long time to heat the water. I had assumed that the immersion heater was just a very low wattage in order to reduce the amperage drawn from the shore power. I have found on occasions that the shore power in some marinas have very low amp fuses and trip if you try and draw to much amperage.
The decision that I had to make was to replace the cylinder or make do with the original cyliner. As I was going to the expense of fitting a new wet central heating installation it would make sense to put a cylinder in line. However the original cylinder only had one heat exchanger coil. I could disconnect the engine coolant system and connect the new heating installation to the cylinder, but that would mean that I would always have to run the heating to heat water and miss out on heat generated by the engine while were on our travels. I had even thought about installing a heat exchanger to the engine coolant system and connect it to the heating system with the view of getting heat from the engine to heat the heating system, but decided that I was going to get little benefit from that arrangement.
The answer was a new cylinder with a double heat exchanger coil. One of the coils is connected to the engine coolant system, the other connected to the heating installation. The only thing was access. I was obvious that the cylinder was installed before the sole had been installed. So careful measurements were made.
However while I had measured the height of the cylinder, I had no accounted for there being a number of studs to the bottom of the cylinder which had nuts to the underside of the supporting timber platform. So it took a while to get to the nuts which was very difficult and there were some choice word shall we say.
In order to get the cylinder passed the engine and the sole, it was necessary for me to cut the insulation and the cylinder only just passed by.
The cylinder was heavy and while lifting it out I lost my grip and the cylinder dropped the cylinder which jammed in the bilge making it difficult to re-lift again. When I finally lifted the cylinder clear of the engine department I found out that I had broken the plastic hose tail fitting. As it happened Sundance was out of the water at the time. If Sundance was in the water sea water would have flooded into the boat with no chance of reaching the valve and little chance of lifting the cylinder out of the way in time. This would have been disastrous and certainly could have sunk Sundance. Luckily the only real damage was to my pride and my pocket as it was necessary to replace the tail hose, this time I have used and brass fitting and took the opportunity to replace the raw water hose.
It transpired that the reason that the immersion heater was very slow to heat the water was because it was caked with calcium deposits. The immersion heater was after all a standard 1 kw.
The new hot water cylinder is very slightly smaller, however it was necessary to cut the insulation to pass by the front of the engine. the cut off section would be put back into place and held in position with tape.
The new hot water cylinder was positioned in such a way that I could easily install the new pipe work and the new immersion heater.
The cylinder was then fitted with a new 1 kw immersion heater and connected to the electric supply ready for use.
The blue pipe at the bottom is the cold water supply to the cylinder while the red and cream pipes at the top is the hot water out which supplies the various taps and the shower. There is a safety pressure relief valve at the top of the cylinder also.
The grey pipes at the bottom of the image are the flow and return pipes of the wet central heating with an automatic vent at the top of the flow pipe. This feeds into a heat exchanger within the cylinder.
The two black pipes which feed into the side of the cylinder are the flow and return pipes to and from the engine. These flow through a heat exchanger within the cylinder. The set up works very well with the cylinder heating very quickly when the heating is on with very hot water coming from the taps. The heating from the engine is very efficient also. The only change I would make to the set up is a valve fitted to the flow and return pipes from the engine. The reason being is that I find that when we are using the heating installation the heat exchanger works in the opposite direction with the cylinder heat exchanger heating the engine coolant system and heating up the engine. Such warming is good if it is intended to start the engine for a passage, however when in a marina or along side for several days or weeks, the engine just acts a big heat sink. The only way I can thing of to prevent the heat sink of the engine, would be to drain down the coolant system to fit a valve, but this could be a bit of a pain to remember to turn on the valve each time we make passage to get some hot water.
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