Examples of changes

Here we describe some control problems past venues have had and our suggestions for improving their heating performance and energy efficiency.

Hall needing to limit user changes

Problem. A hall in high occupancy with a wide range of users including one-off room hires was relying on six thermostatic radiator valves in one big space and a domestic timeswitch that allowed users to turn the heating on permanently. Signage was not enough to keep groups from turning them all the way up or down and the TRVs were getting broken. An aging combi-boiler was also accessible to the public in the kitchen, with user groups turning the boiler thermostat and hot water temperature to maximum, and re-pressuring the boiler themselves, with damage to the boiler as a result.

Solution. They repaired the boiler, had joinery built to hide the controls, and started regular checks on boiler pressure to ensure the fix had worked. They also removed the TRVs and installed a programmable thermostat with a user lock in a prominent position in the hall within wiring range of the boiler. The thermostat contains a radio communicating with a temperature sensor mounted on a column in the middle of the space, giving a better representation of user comfort. The thermostat reliably reads 1C lower than the actual temperature, so they use the offset feature to correct the readings. They chose a Warmworld Dataterm because it gives the right limits for what users can do, but they found they had to write a step-by-step programming guide for the heating operators to understand how to use it. The programmer has optimised start control but they perhaps would have been better off with weather or load compensation as well, given their high occupancy.

Church with unauthorised heating use

Problem. The church had a Drayton Lifestyle timeswitch controlling a 200 kW boiler in an area accessible to church volunteers. This is the timeswitch most commonly found in homes with older boilers, and most people know how to “advance” the heating to turn it on earlier than when it is set to come on. Volunteer cleaners, flower arrangers and the organist were turning on the heating even though it had no effect on comfort in the space while they were in, apart from, in some cases, giving them a warm radiator to touch. In addition, one volunteer was unexpectedly turning the heating on 24 hours ahead for services, longer than the building required.

Solution. This one can be tricky. We’ve seen versions of it several times. One church moved the timeswitch into the boiler room and changed to a less familiar model that was still very cheap. Even though the key is in the door to allow the fire brigade access in an emergency, this was enough to deter casual use. Another used thermal monitoring to work out who was using the timeswitch, explain the problem, and find alternative ways to make the volunteers comfortable, like offering them the opportunity for coffee and biscuits in a small, already heated room, or showing them how to use on-demand electric heating to warm up in an adjacent space, or installing an electric radiator that would get warm to the touch that could be used instead of heating the entire space. Another offered a portable heater, although they need to be careful it isn’t left on or where people can trip over it. Some churches genuinely struggle with these changes because they are concerned about losing volunteers they can’t replace, so think carefully if you are in this position.

Venue heating two halls whenever one was in use

Problem. The venue had 1960s motorised valves separating the halls onto two circuits, wired to a single channel timeswitch with the motorised valves permanently open. Marks on the wall made us suspect that they originally had a second timeswitch, exactly the same, with each one controlling one of the circuits. This was at one time a common arrangement because two channel timeswitches were more expensive and more confusing for volunteers.

Solution. The valves are very robust, with spare parts still available. Their engineer recommended testing the valves, repairing or replacing if necessary, and reinstating the second timeswitch. Valve repair would require the system to be drained, which can be expensive. In the end the venue decided to decarbonise their heating quickly using one of the generous grants that is available, making the change unnecessary.

In a similar situation for a church that lacked separate circuits, they now intend to “zone” the radiators using smart TRVs, although sometimes it’s as cheap to zone it properly through pipework changes.

Church heating an entire sanctuary most days to use a small space at the back

Problem. The only suitable space for community gatherings in the week is a small space at the back of the sanctuary that is difficult to partition from the main space. The heating is one big circuit. The entire sanctuary is used once a week.

Solution. The church is discussing installing radiant heating just at the back for use during the week. This would also let them understand whether their future plan would be to use just radiant heating throughout the sanctuary or a hybrid arrangement with low background space heating when required. This would at first come from the existing gas boiler, but eventually from a heat pump.