Heating a Victorian Church
St Anne's Church is a classic late Victorian church. Built in the 1880's by HRH Prince Arthur, Duke of Connaught, it is arguably too large for the needs of the village it serves.
The original heating must have been hopelessly inadequate: there was a solid fuel furnace in a cellar under the vestry and a duct of about 0.4 m2 cross section took hot air from the cellar to the body of the church, emerging through two cast iron grills in the aisles, with the circulation completed by two grills taking air via a further duct to the furnace. The picture on the right shows the two grills in the centre aisle. The fuel would most likely have been coke, but may have been coal.
I doubt that it is any coincidence that the vents are clustered around the area in which the Duke sat!
There would have been no mechanical blowing of the air, circulation relied upon convection. We may presume that there was some sort of cowl over the furnace to collect the heated air.
A further small duct, about 0.06 m2 cross section, took hot air
to the edge of the chancel, and to the vicar's vestry.
Radiator heating was added, probably in the early 1900's. Some aspects of the work involved were quite significant.
A heat exchanger coil was added to the furnace. This was to prove quite a problem as its life expectancy was short and records from the 1950's indicate that the coil had to be replaced every 5 years at a cost (in the 1950's) of about £200. The system used cast iron pipes, it was unvented and thus operated at high pressure. The effect of this was that the water temperature - and thus the temperature of the pipes and radiators - was a lot higher than we are accustomed to today, to the extent that you could have burnt yourself on them.
Trenches were created across the church at the chancel steps, and again across the doorways and at the back to allow the pipes to traverse the building, and the main heat output was from a loop of wide-diameter pipes running the length of the sides of the building. I wrote earlier of some significant work being involved - the ornate carved stone pulpit was moved, presumably to facilitate the run of the heating pipes, though there may have been an added motivation to stop it obstructing the congregation's view of the chancel and sanctuary. The skill with which the floor tiles were removed and replaced was remarkable. It was only realised that the pulpit had been moved when the church was given an old book of photographs of Bagshot and it was seen that the church interior was not as it is now!
Not all the work was to such a high standard. Alterations to the underside of the pews at the edge of the building (to make way for the heating pipes) is to a far inferior standard than the original building of the pews and is clear confirmation that the wet heating was an addition.
There was no pump in the heating system - it relied upon circulation by convection, and to assist this process some rather unsightly heating pipes were installed high up on the west wall, where they remained until 1995. The original warm air ducts were bricked up.
By the 1950's considerable dissatisfaction was being expressed with the heating. It was considered inadequate, and labour to stoke the boiler was hard to obtain. In 1953 the coke boiler was removed and replaced by a second-hand gas fired boiler, some extra loops were added to the pipe runs at the side, and a fan assisted radiator was installed in the duct between the two vents in the central aisle. The system was changed from a closed, high pressure, one to a conventional vented one - which means that the water temperature will have been lowered. A circulation pump was added. Obviously the change will have solved the problem of needing to employ a stoker for the boiler, and the need to regularly replace the heat exchanger coil in the furnace - but how much improvement it actually made to the heating of the church is not recorded. However the heating system would remain in this state for another 40 years.
When central heating is commonplace
While in the 1950's domestic central heating was the exception, by the 1990's warm houses and warm work-places were taken for granted. The adequacy of the church heating was again on the agenda!
In stages from 1995 various piecemeal improvements were made: additional fan assisted radiators were added and the old boiler (remember, it was second hand when installed in 1953) was replaced with a pair of modern balanced flue boilers. These are much more efficient and so give a better heat output for the same gas consumption.
The heating was now limited by the rate at which the radiators and fan assisted convectors could dissipate heat into the building. In 2000, after much deliberation about the best way forward, and receiving advice from various sourses - some of it contradictory - the church had a further upgrade carried out. The pipe runs at the side of the nave were replaced with proper low level radiators and new panel radiators were installed in numerous places. This increased capacity for dissipating heat into the building allowed a third boiler to be added, together with an adaptive controller that adjusts the heating cycle depending upon the temperature.
There can be no doubt that the new boilers will not last as long as the old one, but with three, at least there is some reserve capacity when one fails! And at last Bagshot has a delightfully warm church!
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