Buildings are responsible for more than 40% of the UK’s carbon emissions and ineffective or poorly controlled heating systems represent a significant factor in this, and therefore a significant opportunity.
Optimising the efficiency of a building’s heating system is a logical starting point and this can be addressed by utilising a boiler’s built-in sophisticated controls. Used appropriately, heating controls can deliver significant fuel cost savings, improve comfort, and help reduce the impact on the environment.
Keston’s C40 and C55 boilers have just celebrated their fifth successful year as pioneers for advanced controls and functionality.
These models offer:
- Dual stat temperature controls – this enables the boiler to switch between two temperature settings, depending on the demand source. This is ideal when different flow temperatures are required, for example, with underfloor heating.
- Weather compensation technology – a built-in weather compensation controller, with an outside sensor, closely monitors outside temperature and adjusts the boiler flow temperature accordingly.
- Opentherm communication – working with intelligent room controls for allowing zoning and sequencing.
- Optional interface with plant room control systems – the boilers can be easily linked with building management systems and are compatible with external control brands via 230V signal or 0-10V DC.
Keston designed both the C40 and C55 with ‘hidden’ buttons that enable installers, in the future, to configure the units and access further sophisticated settings. More advanced users can use the hidden buttons to re-programme almost the whole set-up of the boiler and tailor it to fulfil the needs of a particular installation. This can be a simple change such as capping the range of temperature adjustment available to the end user when underfloor heating has been fitted. This helps to prevent the user inadvertently setting the boiler to a high temperature.
At the more complex end of the scale, it may be advantageous to change the anti-cycle times on the boiler, re-define the weather compensation curve or limit the overshoot on the boiler stat. Whatever the requirement, the C40 and C55 have in-built intelligence that can be activated to achieve total control, greater efficiency and customised heating.
Using weather compensation technology avoids the unnecessary stop/start operation for a boiler therefore boosting efficiency. The controller works in conjunction with an outside sensor that closely monitors outside temperature and adjusts the boiler flow temperature accordingly when serving a heating demand. A built-in controller pushes the flow temperature to as cool as possible, so the return temperature will be such that it allows the boiler to condense for longer without compromising the level of heat in the property. This makes heating affordable all year round not just during the colder months.
Heating engineers generally design systems for a minus one outside temperature, or sometimes lower. Yet when you consider the heating season in the UK, the outside temperature will only be at this design condition for perhaps two weeks of the year. Therefore, for 50 weeks of the year the radiators are running at a higher temperature than necessary resulting in missed additional efficiency savings beyond those they already achieved from the condensing boiler.
In mild winter conditions, and without weather compensation, the boiler will still drive the flow temperature up to 82ºC only to then be switched off by the room thermostat when the required room temperature is exceeded. When the room temperature drops back to below what is required, the boiler fires again striving for an 82ºC flow temperature, and so it goes on. The temperature fluctuation in the room, when the boiler stops and starts, also affects your comfort level.
An open case
Opentherm is a method of communication between heating system components that allows an opentherm-enabled boiler to talk to any compatible controls device.
Standard heating controls will signal a boiler so that it is either on or off. While this may be adequate, at best, for boilers that fire at only one rate, it is not a particularly efficient method for controlling modulating boilers that have the ability to vary their power output on demand.
With opentherm, the controls tell the boiler precisely what temperature and power rate to produce, while the boiler advises the controller what it is actually delivering and if there are any faults. This two-way communication system controls the boiler to a much finer degree, meeting exactly the needs of the building at any time and fully harnessing the potential performance of the boiler.
Keston’s opentherm connection is a low voltage, two-core cabling, that does not invoke any Part P regulation requirements. In addition, the opentherm wires are not polarity dependent, so the connection will work whichever way round the two-wire connection is made.
Close control of the heating system guarantees a stable and accurate building temperature is maintained at all times. Consequently, temperature cycling, typical of an on/off control system, is avoided.
Further benefits of condensing technology are also harnessed. The controls ensure the boiler runs at the lowest temperature, allowing it to run more efficiently for longer. This reduction in cycling will result in improved life expectancy for the boiler, less wear and tear, and will help to reduce C02 emissions.
A plug-in module is also available for building management systems (BMS) that incorporate alternative technology. These devices receive a variable voltage (between 0 and 10V) from the BMS that dictates the temperature the boiler is to work to. The module also provides an output signal to the BMS if the boiler is unable to respond.
To ensure the ultimate efficiency in commercial applications, a multiple boiler rig must include boiler sequencing, weather compensation, optimum start, remote dial in control, room compensation and fax modem output reporting. The Keston rig controller, standard equipment on the Keston rig product, communicates with the boilers using opentherm, instructing them with power and temperature requirements, as well as building a log of exactly how much work each boiler has done. It also ensures that the boilers swap firing order accordingly so that each unit is worked equally over time.
The C40 and C55 can both be incorporated within a bespoke rig – an exclusive service that Keston offers to customers looking for a modular solution that is reliable and hassle-free. The company can accommodate almost any rig requirement, including integrated domestic hot water (DHW) storage, system pumps, and pressurisation units.
Keston Rigs are delivered to site pre-assembled and can include up to five boilers within a floor-standing frame, and up to 20 boilers operating in sequence across multiple frames. The units are supplied pre-assembled and pre-piped
To ensure the ultimate efficiency in commercial applications, a boiler rig must include boiler sequencing, weather compensation, optimum start, remote dial in control, room compensation and fax modem output reporting. The Keston Rig Controller is designed to communicate with the boilers using opentherm, instructing them with power and temperature requirements, as well as building a log of exactly how much work each boiler has done. It also ensures that the boilers swap firing order accordingly so that each unit is worked equally over time.