Installation of H2 Control System
in a Welsh Farmhouse
The client's 250 year old farmhouse lies at 1000 ft in the Brecon Beacons National Park in Wales UK, with thick stone walls, effective loft insulation and double glazing. The existing central heating and hot water system was based on a Baxi Bermuda G.F. Calor Gas (Liquid Propane Gas) Boiler rated at 50,000 BTU (14.62 kW). This had proved effective but the house was in the process of getting a barn extension, and although the Calor Gas system could just about cope it had become extremely expensive to run.
The proposal was to supplement (not replace) the existing system with a Rayburn Supreme Solid Fuel and Wood-burning Cooker which includes a back boiler rated at 35,000 BTU. The farm has several acres of woodland which, with careful coppicing, can supplement the use of coal.
The installed Rayburn Supreme showing the pipe work
The requirement was for a control system which would maximise the efficiency of the boiler combination: in essence taking as much heat as was available from the Solid Fuel boiler and, only if this did not meet the current demand, then activating the Calor Gas boiler to top up the water temperature as required.
There are very few such systems available in the UK. After much research it was decided to use the H2 Control Panel supplied and manufactured by Heating Innovations Ltd., 1A Mill Hill Lane, Knights End Road, March, Cambridgeshire PE15 9QB: Phone 01354-653854.
The H-2 Control Panel designed by Mike Smith is a remarkable piece of equipment. It has no PCBs and consists of pipes and motorized valves, activated entirely by thermostats, whose temperatures can be adjusted to tune the system as required. It is the result of years of research and development.
The H-2 Control System Close up of the Tell-Tale Board
This control system has the following main features:
1. It can be run in three basic modes: Solid Fuel only, Solid fuel plus Automatic Boiler backup, or (if the Solid fuel fire is out) Automatic Boiler only. The second (and third) mode is called Link-Fuel mode.
2. Solid Fuel only is pretty much self explanatory. There is a solid fuel pipe thermostat which prevents the system demanding heat when the solid fuel boiler temperature is so low that there may be a possibility of acid condensation damage to the fire box.
Closer view of the pipe work showing the solid fuel pipe thermostat at the top. The extra vertical pipe on the right is an anti-sludge pipe.
3. When Link-Fuel is activated the system takes as much heat from the Solid Fuel boiler as necessary. If and only if the water temperature does not reach the required thermostat setting, then the control system will activate the Calor Gas boiler (this could of course be an oil fired or electrical boiler) and top up the temperature as required.
4. If the system is set for hot water only, and excess heat is generated once the hot water temperature reaches the preset maximum, then the excess heat will be dumped first into the dump radiator and then if necessary into the full radiator system. With careful solid fuel boiler management the latter is a rare event.
5. In the event of power failure excess heat from the solid fuel boiler is dumped by gravity based convection into the dump radiator.
The system requires plumbing into the existing Central Heating and Hot Water System, and electrical connections from the H-2 Board to the existing Gas Boiler. The plumbing is relatively straightforward but the instructions must be followed carefully. The H2-system is most easily installed upstairs in a house but it can be installed in a bungalow (single level home) if required.
The instructions for the electrical connections could be a little clearer. Although the electrical wiring was installed by an extremely professional electrical company, who were very enthusiastic about the project, in the first instance they got it wrong. The H-2 Board must control the Gas boiler and not the other way around! Still, Heating Innovations were very helpful and, when advised of the problems, immediately visited (charging only travelling expenses) and corrected the wiring error.
Client's Evaluation
When we did the barn conversion there was a lot of building work and plumbing going on and we absorbed some of the plumbing costs of installation of the H2-Control Board into the general upgrade. We placed it in the airing cupboard upstairs. The Rayburn was installed about one year later. The creation of a new fireplace in keeping with the original (which had been filled in by a previous owner who installed a horrible gas fire) was both exciting (we uncovered the old bread oven and a meat smoker in the chimney) and expensive. The extra pipe work connecting the Rayburn to the H2 Board was not a major budget item.
After the initial wiring-up problem was rectified the system has functioned flawlessly. Not having a PCB is good because we get lightning storms from time to time and the simple electrical design means the system is less susceptible to voltage spikes.
Eva-Pro did a first rate job on the plumbing and their installation was praised by Mike Smith, the designer of the H2-Board.
Before the system was up and running we had a very hard winter (up here with the wind and snow that is no joke) and the large barn conversion room was being used all day. Our Calor Gas bill went through the roof, even though the conversion had paid very careful attention to insulation.
The system has been running since February 2002. So we have to date got the full benefit only for less than half of the winter. Therefore the initial costings are preliminary. However, we are absolutely delighted with the results. We estimate that so far our Calor Gas bill has been reduced by 80%. True we are now buying some coal, but compared to the cost of Calor Gas the coal bill is insignificant. We are also supplementing the coal with wood from the farm. Overall, including the fireplace work, we figure the system will pay for itself in about four to five years. Without the fireplace work it would probably pay for itself in two years at most.
The Rayburn took about a month to get the hang of. It is lovely to look at, the living room is always warm and we can cook on it too.
We rate this aspect of the farm upgrade as a total success (actually it is all pretty good!).
P.S. The first plumber we tried attempted to talk us out of the project. When we persisted he didn't want to know. Eva-Pro ended up doing all the plumbing upgrade work on the farm.