Wesley Grange is a sheltered housing scheme on the Wirral, it was built in 1982 and was heated by four Hamworthy UR300 conventional boilers. The extent of the controls for the scheme was a time clock which provided automatic timed control to the heating system. When the time clock was calling for heat all four boilers would run to the boiler thermostat setting which was 75degC, and would be circulated around the building 365 days of the year.
The challenge was to replace the conventional boilers with high efficient gas fired condensing boilers and a control system that would provide the scheme with a comfortable temperature throughout the year whilst reducing running costs considerably.
With a small window of opportunity in an unpredictable summer careful planning was required to strip out the old boilers and install the new condensing boilers so as to limit the schemes exposure without heat to a minimum. The installation went smoothly which then allowed time for addition isolation valves to be installed to the heating system and mains cold water system in the roof space so that sections of the scheme could be isolated independently in case of an emergency or future works, previously the whole system would have to be switched off and drained down.
The three new Potterton Sirius boilers have been installed on a rig and configured to share the heating load of the scheme, the controls monitor the outside air temperature and the space temperature within the building. The control system calculates the optimum time to start the heating system to bring the building up to temperature before calculating the compensated heating flow temperature against the outside air temperature to maintain the space temperature within the facility. The combination of the boilers running in condensing mode and the reduction in wasted heat from overheating the housing will provide substantial savings in the future along with a more comfortable environment.