installer sitting on floor looking at a document on tablet computer


If you’ve got a query on a technical issue, we have lots of information in our technical tips and FAQs. But if you can’t find what you are looking for then send a tweet to @DraytonHeating, email, or call our technical support team on 0333 6000 622.

Jargon Buster

Confused by technical terms?  Have a look at the information below to help you understand what they really mean.

On/Off load compensation

On/Off load compensation is a feature of temperature control products such as room thermostats and programmable thermostats.

On/Off load compensation is a proven method of minimising energy use by calculating the demand from a thermostat. As the temperature approaches the required setting, the boiler will fire for shorter periods of time, ensuring a constant temperature is maintained. This not only enhances comfort levels, but also uses less energy. On/Off load compensating products are ideal for use with modern systems in well-insulated houses.

Intelligent Delayed Start

Intelligent delayed start is an option on all Drayton programmable thermostats.

Most people will set their heating to come on an hour before they get up to ensure the rooms are up to temperature. On a milder day, a full hour is probably not required which means the heating is on for longer than required. Intelligent delayed start senses the temperature and delays firing the boiler until the latest possible time, meaning additional energy savings of up to 10% without compromising comfort.


RF stands for radio frequency, which is how wireless devices operate - They talk to the boiler via radio frequencies rather than being wired.


Time switches work with a combination boiler and will allow you to set your heating and hot water to come on at the same time.


Programmers are used if you have a separate boiler and hot water tank. They enable you to control when your hot water and central heating come on separately.

Room Thermostat

A room thermostat senses the temperature of the air and adjusts your heating system accordingly to achieve the desired temperature. Once the room reaches that temperature the central heating will be turned off. If the air temperature drops below the thermostat setting the heating will switch on.

If you are using your thermostat in conjunction with a time control it will only work when the time control has the heating set to be ‘on.’ However, the room thermostat will trigger the heating system to turn off once it senses the required temperature has been reached.

Programmable Room Thermostat

A programmable room thermostat combines temperature and time control in one unit, allowing you to set different temperatures for different times of the day.

Smart Thermostat

A smart thermostat is an internet connected heating control that allows you to manage your home’s temperature and heating schedules from a remote location, using your smartphone, tablet or wearable device such as an Apple Watch.

Thermostatic Radiator Valves (TRVs)

Thermostatic radiator valves (TRVs) enable you to be more energy efficient, by preventing rooms from overheating. They allow you to set different temperatures in different rooms and also enable you to turn off the radiator in rooms that are not being used. This can help to reduce energy bills and increase comfort levels.

Service Interval

Service Interval is a feature that restricts a tenant’s heating and hot water provision until they have the boiler serviced. When the Service Interval control is fitted, the installer will set the service date.

Shortly before the service is due, the control will alert the householder, in order for them to have the maintenance work carried out. If the service is missed the device reduces comfort levels until the boiler is serviced and the unit reset.


ErP stands for ‘Energy-related Products’, and the ErP directive is a new regulation set by the European Union. The regulations have been put in place in order to improve the efficiency of heating and hot water products.

The aim is to inform and educate homeowners about the efficiency of their appliances, by a placing a clearly displayed energy label on the product.


TELL is the product classification system of the European TRV industry, which gives each TRV an energy rating. The rating is based on how quickly a TRV reacts to changes in room temperature, how effectively it maintains stable room temperatures and how it performs after changes in water temperature and system pressure.

TRVs can receive a rating of Class I to IV, with I being the most energy efficient and IV the least efficient. Drayton’s TRV4 achieved the highest Class I energy efficiency rating, thanks to its ultra-sensitive liquid-filled chrome head, which reacts swiftly to temperature changes to minimise energy use.