Today, installers are in a great place to help consumers take advantage of the benefits that boiler controls can bring with a range of options that deliver better fuel efficiency at an affordable price.
If advanced controls are correct for the home and the heating system, then boilers can operate at the peak of their efficiency, using the minimum amount of fuel necessary to heat the property.
Weather Compensation is one very straightforward control add-on that can improve heating performance by aligning the boiler flow and return temperatures to the outside conditions. An external sensor communicates with the boiler directly allowing it to align the heating flow temperature with prevailing weather conditions. This is desirable because condensing boilers become more efficient the cooler the temperature they operate at.
The location of the sensor is important as positioning it in areas where direct sunlight will fall can affect the feedback it sends to the boiler. A north facing wall is ideal and 2-3m is a suggested fixing height, but location beneath the eaves will normally keep sunlight from reaching the sensor. It is important not to locate the sensor next to windows or extract fans where the air leaving the building will be warmer. For hard wired sensors, running the cable alongside power or lighting cables for any distance should be avoided as induction from the higher voltage can affect the low voltage signal communication between the boiler and sensor.
When using weather compensation, the installer will need to assess the property’s existing or proposed heating system, note its geographic location and then adjust the boiler performance to suit the situation; this assessment is called setting the heating curve.
To set the heating curve installers first need to determine the heating flow temperature necessary to enable the radiators or heat emitters to warm the property to say 20˚C internally when the weather is at its worst in the area. Also it is important to determine the lowest likely external temperature expected in the area or the customer’s own preference. Once you have these two figures you can find the heating curve on the graph supplied with the boiler or controller.
Estimations or calculation errors can occur and, should there be a discrepancy in setting the curve to suit the existing system, the user can still adjust their level of comfort by using the heating flow temperature selector not the room thermostat or TRVs.
For example, as soon as the external sensor is connected to the appliance by the engineer, an icon will appear on the appliance display to indicate an external sensor has been detected and is now connected to the appliance. At this point, the default ‘climatic or heating’ curve will be selected but if it is necessary the engineer can select a more appropriate curve for a particular system. During a heating request, the boiler will interrogate the external sensor and read the outside temperature, before calculating the flow temperature required to provide an internal 20˚C room temperature. If this results in an uncomfortably warm or cold room temperature, the end user can make a further – fine – adjustment, by moving the appliance temperature selector on the boiler by 1˚C steps, to either increase or decrease the room temperature by 1˚C, i.e. from 15˚C to 25˚C.
Of course it is possible for the user to adjust the room thermostat or TRVs to reduce the air temperature but that would leave the boiler flow temperature higher than it need be. In the first instance, it is best to adjust the heating curve to supply water to the heating system cooler and then regulate air temperature by the room thermostat.
At Vokèra we have recently launched a new controls course which will help installers gain a better understanding of the benefits that can be passed onto the homeowner by improved control. We can also help installers understand and appreciate the value of setting the heating curve. To register for the course, email [email protected] and find out how controls can help add value to your business and cut fuel bills for customers.
