Boilers should be sized to provide sufficient heat to provide hot water and warm the dwelling to the required comfort temperatures when the temperature outside is below freezing. (Historically this has been -1C although more recently -3C is being recommended as optimum measures)
This means that for most of the heating season, during times of the day when comfort temperatures are required, the boiler will produce more heat than can be used by the system.
The heat excess to requirements is lost via the flue through convection. the cooling air entering at the base of the boiler cools so that it fires up again, even if the system does not need any heat at that time. when the internal thermostat recognises the required temperature setting the burner is switched off but the heat produced is going nowhere except out of the flue. the boiler is doing what is known as short-cycling.
If the boiler is over-sized even when it is freezing outside, the amount of heat wasted is significantly increased throughout all of the heating season.
We are proud to be registered Vaillant boiler installers, as we consider them to be the very best quality and value, something we strive to provide our customers with at all times. As registered installers, we can offer a 5 year guarantee on all our Vaillant boilers installations, demonstrating our total confidence in the product, installation and after sales service.
We install Grant oil condensing boilers as standard and are confident that we can cater to meet with all your requirements whilst meeting all current regulations. Within the oil range, we can install combination, open vented and system boilers, indoor, outdoor and wall hung versions, all with various flue options enabling versatility in positioning the boiler.