While OpenTherm may have been around for some time, there is still some confusion about this technology and how it can benefit homeowners. Jamie Bennett, Engineering Director at Drayton, explains exactly what OpenTherm is and how it works.
Nowadays, boilers are more efficient than ever, however homeowners are always looking for ways to get that little bit more out of their heating system. OpenTherm is a protocol that communicates information between heating controls and the boiler, to better regulate the temperature flow through the heating system and maximise efficiency.
How does it work?
Modern thermostats use on/off load compensation to adjust the average water temperature within the heating system, by cycling the boiler periodically. In contrast, OpenTherm works by directly adjusting the desired water temperature within the system from the boiler itself.
During ‘high load’ conditions – such as when the boiler is on for longer periods to heat up a cold room – a high water setpoint can be requested from the boiler with OpenTherm controls. The water temperature being requested will then reduce over time, as the room temperature approaches its target.
The important difference here is that an OpenTherm boiler with OpenTherm controls will run for longer periods, but produce water at lower temperatures. This uses less energy and maximises the time spent in the higher efficiency condensing mode.
What are the benefits?
The main benefit of OpenTherm controls is being able to offer your customer more stable and accurate room temperature control, even when compared with on/off load compensation controls. This means that less energy is required from the boiler to keep the rooms at the right temperature, helping to reduce energy bills.
Another key benefit for installers is that OpenTherm controls can often make it easier to find important data during servicing or callouts. Depending on the type of control, installers are often able to access information about how long the boiler has run for, how many times the system has reset, and any faults that have occurred, all of which can help save time when troubleshooting. In the future, it’s expected that this data will also help installers to take more preventative measures and predict boiler diagnostics, before a breakdown happens.
Installers can find out whether a heating control is designed with OpenTherm technology by checking product packaging and marketing materials. If it is not clearly indicated, engineers can check the wiring diagrams or visit the OpenTherm Association website – opentherm.eu.
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