Friday, 23 January 2015

Heating Update, halfway thru winter.

Well I thought you might like to know what's what now that we've had time to get to know each other.  I so wish that I could have fitted this system when starting the build ten years ago.  Things have changed, condensing boilers are reliable and cheap, heating controllers have computers in them and can be installed easily.  All this means that your expensive fuel does the best job it can, and what a job!

Let's recap on the system -

Worcester Bosch Greenstar Danesmoor System Boiler 12/18 set up for 12kW/hr.  This was easily done in-house with the help of a pressure gauge from BES plumbing.

One zone is for the domestic hot water, with the tank thermostat set for 55C.  Any higher and the settings on the boiler means that it might not reach tank temperature and remain on all the time.  This zone is controlled by a programmable timer.   Legionella control is set on a separate timer to 60C via 1kW immersion heater.  It does this once a week.  Keeping the return to boiler water temperature near 50C means that it operates in condense mode thus reaping the economy benefits.  Too high a return temperature and it just operates like a normal oil boiler.  Even working in this mode it would still be more economical than the old drip feed.

Another zone is for the forward part of the vessel and is controlled by a programmable room thermostat.  On-call means we are up at night  or arrive back late or early sometimes.  We want the boat warm at three in the morning.  The thermostats have up to six timer settings for the temperature so we can ramp up or down how we want room at particular times of the day.

The third zone control is for the aft sleeping cabin and is set to suit but never gets cold or too hot, brilliant.

The old system used around 6 litres of diesel for a twelve hour overnight period and it was often too hot.  During the day if we  needed heat I would light the wood stove.  The new setup is averaging 4.2 litres per 24 hours during the cold months.  Remember the boat is now being kept comfortably warm 24/7.  A significant saving and perfect temperature control.  It is averaging 1kWhr a day of electricity to run it but with the solar power I can live with that.  Most folk would have the system off at night or have a lower temperature setting and have it warm up in the morning.

Next thing is to put some heating in the wheelhouse.  It did have a pipe radiator in there originally but it was too hot as the boiler flue also went though the space.  I took it out to leave the heat from the flue doing the heating.  Now with a balanced flue there is now heat loss and the wheelhouse can get a bit chilly.  Strangely the heat from both ends of the boat doesn't seem to rise into the wheelhouse, there is some sort of inversion going on, why I don't know.

I shall probably make a narrow type of towel rail radiator out of all the unused copper fittings and pipe offcuts and use the holes where the old pipe radiator came through.

If we want a proper fire it's there and the zone shuts down but the rest of the boat is toasty and the woodstove is still there as a back up.  Installing the domestic system is cheap compared to a marine one.  Ok the boiler is bigger but not that much, if it goes wrong and I can't fix it there are hundreds of domestic heating engineers who can.  Because there are thousands of these boilers around spare parts are relatively cheap and easy to get hold of too.  Noise wise I find it fine, actually it's rather comforting to hear it fire up in the background.  I mean they are fitted in kitchens on land so they can't be that bad.  I know a friend who mounted the boiler on rubber mounts on a oil tight sub frame with silicone hose on the pipe connections.  A truly immaculate installation and a steel boat can transmit noise but I didn't think I needed it and I still don't.

To summarise, a superb system that keeps us warm and is fully controllable and very economical.  With no wood chopping or humping sacks of coal, fantastic.


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.