Why is M2G required? What does M2G do?

M2G prevents an inherent problem

  • Some boilers within an estate, no matter how modern, can waste heat as a consequence of standing losses and poor temperature controls
  • Boilers can often fire to only recover these standing losses
  • This is known as "boiler dry cycling"
  • Boiler dry cycling is a widely recognised industry problem
  • By preventing dry cycling energy consumption can typically be reduced by between 10% and 25%
  • Typical payback is achieved within 2 years
  • M2G is designed to specifically identifying and preventing boiler dry cycling and assit with short cycling
Click here to find out how M2G prevents boiler dry cycling

  What is boiler dry cycling?

  • The boiler fires to reach its set point (determined by the boilers thermostat or other controls e.g. BMS) to meet the building's heating demands (load)
  • Now the set point has been reached the boiler stops firing. However, the boiler loses heat via its casing or/and flue and begins to cool down. This is known as standing losses.
  • Once the temperature drops to a certain point typically 2.5oC below the set point, the boiler will then fire unnecessarily just to recover the standing losses even though the building/load requires no heat
  • Dry cycling occurs in all boilers regardless of the age and size - it is an industry wide problem, often going unnoticed

Radiated heat losses (standing losses) whilst boiler is firing and during stand by

How does M2G prevent boiler dry cycling?

M2G is an advanced intelligent retrofit boiler optimisation control (European Patent number 1607820) that optimises the efficiency of each individual boiler. Suitable boiler types include atmospheric, forced draught, modular, condensing and modulating. This includes natural gas, Class C oil or Class D oil, and LPG fired boilers. M2G is not appicable for steam or biomass boilers or direct fired hot water generators.

M2G is designed to specifically address the inherent problem of boiler dry cycling. M2G integrates with the existing BMS, sequencing, optimum start control and weather compensation. M2G complements these controls and is not an alternative to these control strategies. As a result typical energy savings of between 10% and 25% can be achieved over and above these controls. Payback is typically under 2 years and each M2G has a 5 year warranty.

How does M2G work?

A M2G is mounted to each boiler. The M2G is wired into the same control circuit as other auxiliary controls e.g. BMS, time clocks etc. M2G does not invalidate the boiler manufacturers warranty.

Two digital temperature sensors are strapped to the flow and return pipe work of the boiler. The installation is non intrusive, with no downtime to the heating and hot water systems. Installation typically takes 90 minutes per boiler.

Image A: Illustrates a typical M2G installation. One M2G is required per boiler (For modular boilers a M2G and master slave solution is available - please contact us for further details)

Image B: Illustrates the attachment of one of the M2Gs digital temperature sensors. Two digital sensors are fitted to flow and return pipework of each boiler. This enables M2G to measure the individual boilers flow and return temperatures in real time and analyse the boiler's current temperature profile/load.

Real time analysis

Once the boiler has reached its designed set point, the M2G establishes the current load profile. This is done by recording the current designed setpoint and immediately monitors the temperature decay of the water in the flow and return every second and analyses this data every 10 seconds. This real time measurement and analysis enables the M2G to profile the load (heating demand) on the boiler. The M2Gs adaptive algorthrims calculate whether the load on the boiler is genuine, or if the boiler is attempting to fire unnecessarily as a consequence of its standing losses i.e. dry cycling.  M2G instantly recognises a true demand and immediately allows the boiler to fire to meet this. M2G does not alter any designed boiler set points or effects comfort temperatures (heating and hot water).

Importantly, the M2G's control strategy is based on temperature not time or firing patterns.


The M2G can be easily transferred to replacement boilers as part of your asset lifecyle plans. Each M2G has a 5 years warranty with a lifetime exceeding 10 years. The M2G requires no readjustment or calibration once installed.

The M2G interface/interlocks in the following way:

a) Your boiler(s),

The M2G is wired in series with the existing boiler thermostat circuit, ensuring that existing boiler thermostat set point (temperature) is always maintained and controlled. In all cases, the primary safety controls of the burner/boiler are not compromised or interrupted.

b) Your BMS (Building Management System)

The M2G system can be interfaced with all types of BMS/ BEMS strategies and is non-intrusive to the building’s controls (Variable Temperature, On Demand control, sequencing and weather compensation and preset comfort levels. When M2G is installed alongside a BMS/boiler control - M2G is directly controlled by the BMS.

c) Your existing boiler house controls:

The M2G will work with and complement existing controls such as: Weather Compensation, Heating Optimisers Controls, Variable Temperaure control, On Demand control and Boiler Sequencing Controls.

M2G digital temperature sensors installation:

The M2G measures the boiler flow and return temperatures individually on each boilers, these are a surface mount method that is completely non intrusive to the system pipe work. The sensors are fixed mechanically and does not require system “drain down”.

Further information:

  • Why it is necessary to go beyond the exisitng BMS, please click here
  • What do you need to consider when specifying boiler load optimisation? Click here to find out

To find out more please call:

0800 082 18 18 or email reduceco2@sabien-tech.co.uk