Thursday, 8 January 2015

Heating update.

The original heating system was by a drip feed diesel Kabola E7, a reliable bulletproof boiler that was built for the sea.  It has gone to another barge via a well known selling website.

It ran an 1 1/4" large bore thermo-syphon feeding big cast iron radiators via 3/4" tails, thus no electricity for the boiler or pumps.

 At a later stage the multi-fuel stove had a back boiler fitted which was tee'd into the top end feeding the bathroom and office.  Whilst this kept the front of the barge nice and warm when the boiler wasn't needed, it did mean the stove ran cold and we had a lot of tar on the decks from the chimney.  Decommissioning the back boiler sorted that problem but did nothing to heat the front of the boat other than by the stove being in  the vicinity unless the central heating was fired up.

Fuel prices have gone up 400% since starting the barge, this means that the limited control drip feed boiler was proving rather expensive to run.  A new more up to date system was required.  Research suggested a Worcester Bosch condensing oil boiler might be the way to go.  So at the end of the summer and before any cold weather was due the old system was taken out.  Many meters of carefully crafted galvanised steel pipe were removed along with the not too old Kabola 7 kW drip feed.

The mount frame needed modifying to suit the new Bosch and copper pipework bent up to suit the new design.  The lower sub frame had to he heightened to match the one at the back so there was enough room to get the deeper boiler in.  There was just enough room to get the flue bends in!

The radiators had to be modified from top in bottom out to bottom in bottom out and a couple of traditional thermostatic mixing valves (TMVs) used in the office and heads.

Three zone valves were used to separate the hot water, aft cabin and forward section.

This means that if we have the stove going and thermostat shuts the heating off then the bedroom in the aft section will still be heated on its own circuit as will the domestic hot water.

One of the engine room fuel tanks was drained and refilled with heating oil instead of diesel and plumbed into the new boiler via a CAV watertrap and filter.  And talking of filters, condensing boilers in particular don't like bits in them.  I fitted a magnetic swirly filter that can be "blown down" for cleaning.  Just below it you can see the condense pipe in white which empties via a Marelon skin fitting, again to avoid problems with metal and the acidic condense.

The boiler runs off its own dedicated 500 Watt  sine wave inverter with the option of shore power if available.

Programmable room thermostats are used in the saloon and aft cabin.

These are brilliant and allow the temperature to be varied at different times of the day and stops the barge losing too much overnight when it's cold.  Hot water is kept at 50C with a 60C anti Legionnaire's disease boost.

I used the flue system for the boiler.  It is a balanced flue which means the incoming air is drawn in around the exhaust pipe, so we don't need a barometric damper like the Kabola.  Weirdly the exhaust part of the flue is plastic, I guess in is cold enough being a condensing boiler and the acidic gasses won't harm it.


It is a neat system which neatly replaces the original Kabola flue almost exactly.  It was critical to get this right as it could have made a right mess of the wheelhouse.  The flue cap too is pretty neat.

I used to light the old boiler around 7 PM in the evening and run it overnight until 8 AM unless it was cold enough to have it running 24/7.  It used an average of 4-6 litres per day.  The multi-fuel stove kept us warm during the day if we needed it.  The last three months have averaged 4 litres per day with it running 24 hours a day.  The stove has rarely been lit.  This means that the new boiler is twice as efficient in keeping the barge warm.  OK we have not had a harsh winter so far and it does us quite a lot of our precious electrons for the pump and control valves.  This is mitigated somewhat by the fact that our water is no longer heated via the immersion heater at least in the winter months.  Initial measurements indicate that it is consuming around 1.4kWhrs over 24 hours.

Being a system boiler, the pump and expansion tank are inside the casing which is good because physically it is quite a bit bigger than the old one.  All the pipework had to be finished before sliding the boiler back for the final connections.  I was pretty easy to bolt the boiler down so it was not going to walk away in a sea.
Setting it up for the lower 12kW output was pretty simple as it only required changing the pressure jet and primary air mixture disk with a tweak to up the oil pressure a bit to 132 psi.  I didn't bother getting the flue gas analysed as the "magic eye" that monitors the flame has not sooted up and everything seems within limits.  True enough it is not as quiet than the old system as the pump, fans and motorised valves do make some noise.  Do I find it offensive, no, and I am fussy about noise.  It does use electricity and it is more complicated but it is so warm and easy to use.  Best of all there is no messing about lighting fires and boilers.  I almost wish I had fitted it from when the barge was new but then technology has moved on.  I now have an up-to-date and economical system and any domestic heating engineer can fix it if I can't, brilliant.

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