This blog article from our Technical Support Manager Chris Lamprill gives you a guide to controlling your heating system in your building. To control your heating system, you usually need to think about to types of control – thermostatic control and time control.
This controls the temperature and would normally be set for a given temperature (e.g. 16oC, 18 oC, 20 oC, 22 oC etc.).
This determines whether the heating is on and would normally be set for given times, such as 09:00 –17:00, Monday – Friday. These two controls (which are sometimes contained within a single unit) enable you to take control of the key parameters for your heating system. However, there are other things to take into consideration:
When the building contains water pipework it is essential to protect the pipework from freezing using the frost protection setting. There may also be other items in the building that are susceptible to damage by low temperatures (e.g. electronics, chemicals, plants) so it is worth checking these to determine the lowest temperature that would be acceptable for your particular circumstances. The frost/low temperature protection can then be set to this temperature. Care should be taken not to set low temperature protection too high as this will increase heating bills.
If a property is kept at low temperature overnight, or for weekends, it may take the heating system a while to restore the required temperature when the building is occupied. Some thermostats have self-learning programs that adjust the heating time to compensate for this period. If this is not available you may need to set the time control to bring the heating on a little earlier – typically 30 to 60 minutes depending on the system and outdoor temperatures.
You may feel that there is no need to be heating a property just before the end of the timed period. Where a self-learning program is available this will reduce the optimum heating gradually over a set period until the end of timed period is reached. If this is not available you may need to set the end period earlier than the occupied time required, perhaps 15 minutes before the end of the occupied time set on the time control.
For both warming up and cooling off periods a little trial and error will soon determine the optimum time settings.
Some systems are able to modulate or switch between high and low firing when the set point temperature has been reached, thereby using less fuel to maintain this optimum temperature. This is a more efficient arrangement than continually switching the heating on and off.
A modulating system will typically run at 100% up to a temperature that is slightly below the set point, and then reduce the heat output so that the heating gradually reaches the optimum temperature and does not ‘overshoot’.
Siting of the thermostat is important in that it must be fitted where the temperature will be generally representative of the area to be heated. It should be installed 1.7m above floor level (unless a remote sensor is being used, see below) and away from draughty areas or areas subjected to direct heat from sunlight, radiators etc. It should also be in a position that is easily accessible for programming and operation. Where the thermostat uses a remote sensor, the location of this sensor should comply with the criteria described above.
In some circumstances it may be desirable to switch off the heating when there is likely to be a significant waste of heat, such as when a loading bay door is opened. To facilitate this, a mechanical switch can be installed that is triggered by the opening and closing of the door.