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.
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.
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.