Heating engineers will soon see open protocols become a regulatory requirement and a customer expectation.
So, what are they? Open protocols allow controls and boilers to exchange information in real time, enabling the boiler to modulate output to match heating demand precisely, rather than using inefficient on/off cycling.
Upcoming regulations
- The government’s consultation proposes all temperature controls and gas combination boilers use open protocols by mid-2026
- Gas combination boilers ≤45 kW will need to modulate down to 15% of maximum output without on/off cycling by mid-2028
- Boilers will be supplied with a 60°C low flow temperature default to optimise efficiency and system compatibility
Why it matters
- Reduces gas usage by maintaining low flow temperatures and avoiding overshooting demand.
- Decreases wear and tear by preventing constant cycling.
- Simplifies fault finding when controls display diagnostic codes sent by the boiler, reducing time on site.
How to prepare
- Ensure familiarity with OpenTherm and other open protocol systems.
- Upskill on commissioning open protocol-enabled controls with boilers for optimal modulation and efficiency
- Educate customers on the benefits of using compatible controls rather than sticking with simple on/off thermostats.
- Understand balancing requirements for modulating systems to maximise performance.
As boilers and controls increasingly use open protocols, heating engineers who are ahead in specifying, installing, and troubleshooting these systems will give better value, have fewer call-backs, and deliver systems that are compliant with future regulations and customer sustainability expectations.