TECH TALK – OpenTherm

John Lawton, Technical Product Manager at Intergas, discusses why OpenTherm is so important to the efficient running of your customers’ central heating systems…

OpenTherm is the name of a non-manufacturer-dependent system of communication between modulating heating appliances (central heating appliances) and room thermostats. The system consists of a communication protocol and an interface specification. OpenTherm is a futuristic system, which combines simple installation techniques with high functionality and future expansion possibilities.

Basically, OpenTherm communications allow the transfer of heat demand information from the thermostat to the boiler enabling it to proportionally control the flame size and lower the flow temperature as the room approaches set point. This means there is minimal overshoot of set temperature and the room temperature is maintained at the comfort level more accurately. It also means the return temperature is kept low, which is of particular importance to the efficiency of condensing boilers. It is a way to achieve ‘load compensation’ as defined by Building Regulations and is an open standard that multiple controls and boiler manufacturers have successfully used for decades.

It can help the boiler to modulate and run more efficiently in condensing mode for longer periods. All Intergas boilers are OpenTherm compliant in the UK, helping the installer comply with the regulations – SAP, ErP and Boiler Plus.