St John the Evangelist, Hildenborough
Our photo shows Dan in contemplation, in the graveyard of St John the Evangelist, in Hildenborough, Kent. Actually, he’s assisting in a purging operation at the gas meter box.
This church, constructed over 100 years ago, was heated by an old 86kW Ideal Buccaneer commercial boiler. The boiler had a reputation for breaking down in the hour of need (eg: coldest days of winter) and the management team had found the only way to minimise the chances of failure was to have the boiler on in periods of the summer.
Old Buccaneer boiler
The heating was controlled by a bewildering set of high/low thermostats and timeswitches, and it wasn’t clear to any of the users what, if any, effect they had on the heating. Large gas bills were being incurred all year round, and the church treasurer concluded that the sooner a solution was found, the earlier savings could begin.
The church management committee wanted a new system, preferably a high efficiency condensing replacement. The church has a listed exterior, and the boiler plant is in the basement, with a restricted ceiling height.
Interior view of St John the Evangelist
The job was put out to tender; Hot Water & Central Heating were the only company to propose a modern high efficiency solution. We suggested a Viessmann Vitocrossal 200 series, which would be a reasonable fit in the congested boiler room, and importantly, it has a very low level flue outlet. The boiler has an efficiency in excess of 90%, and is exceptionally quiet in operation.
The flue system in a condensing boiler installation requires non corrosive materials, typically stainless steel or plastic in construction. The system we chose for this job was a Viessmann product, made by Skoberne, and consisted of 150mm diameter plastics sections. Running the flue outside was not possible due to the aesthetics, so we devised a way of using the old chimney annulus for the majority of the route, with a small break in point in the church to facilitate a swept bend.
This was the only visible works, later boxed in
The old cast iron boiler was broken up and removed. The opportunity was taken to renew the lighting in the boiler room with 4x55w fluorescent weatherproof battens, which was part of our quotation – as the 60watt bulb was not very effective in a black room.
Part of the old boiler awaiting the scrap contractor
We arranged for scaffolding to be put up around the chimney, as it is over 35feet high, and the installation proceeded apace.
Rick Johnson, our brick maestro subcontractor
The new boiler was installed, together with new pumps and controls.
Vitocrossal 200 stainless steel heat exchanger
We altered the layout of the steel threaded pipework and the gas supply; the Viessmann Matrix burner and casings were fitted, together with the integrated Vitotrol 100 controls.
Nearly finished!
Finally, the rooftop work was completed and the scaffolding removed.
Finished chimney termination
The last bit is how the church’s many users will control the heating. We’ve configured the boiler to work with a standard domestic Honeywell programmable room thermostat. This will enable the management team to preprogramme temperature levels for the week, keeping the building on a low level heat when unoccupied and at comfortable levels when in use.
Honeywell programmable thermostat
Temperature settings can easily be overriden by church users, but any changes made are temporary – the CM927 we have used will be familiar to many as the easiest to use temperature control currently available.
Many building services engineers fit complex heating controls, but in multi-occupancy buildings there is often no permanently employed person to manage the system, and it is effectively running out of control. We believe in making things as simple as possible, this is the only way comfort and efficiency can exist together.
The Viessmann Vitocrossal is a premium product, superbly engineered, and should last many years in this application, whilst reducing energy usage by over 30%.
2017 Footnote:
Comparing energy readings over the last few years, to those when the outgoing boiler was in use, the church management team are delighted to report that the installation has saved gas usage by approaching 50%, considerably in excess of their expectation.
We have subsequently updated the control system across the church complex to Evohome in 2016, and linked it to the main church building, where Evohome also controls 5 function rooms, an 80Kw Kidd VHE Model 260 (installed by us in 2006), and some 1980s radiant electric heating.
