F.A.Q.

How does the M2G work?

The M2G is a microprocessor-based controller that optimizes heating based on boiler load. The M2G works on hydronic boilers to reduce dry cycling, allowing the boiler to fire when there is an actual “Call for Heat” and to delay firing when system demand is low.

M2G VideoM2G SpecificationsWill It Work On My Boiler?Savings Calculator
Yes No
Closed-Loop Hot Water Boliers Steam Boilers
Boilers that experience normal cycling behavior Conventional domestic hot water heaters
Natural Gas, Propane, LPG, or Oil Electric Boilers
Single or multiple boiler configurations (one M2G per boiler) Boilers that don’t cycle
Single Stage, Multi-Stage, or Modulating boilers RBI Boilers controlled on building return
Systems with or without existing temperature reset controls) Boilers that don’t cycle (either run continuously or rarely)
Systems with or without existing Building Management
Systems (BMS)
Boilers with greater than 15°F dead band
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Why does it work?

Space-heating boiler systems are designed to be able to handle the coldest days with some extra buffer. This means that throughout much of the year, the boiler is running below its maximum output. In this case, the boiler will “dry cycle” to compensate for standing losses rather than actual building demand. The M2G reduces the number of boiler cycles, which leads to reduced energy and maintenance costs without affecting internal building temperature.

Why don’t I just widen the dead band, or find another way to delay firing?

Changing the dead band leads to much greater variability in building temperature. This causes complaints from building occupants about being too cold and too hot. Delaying every firing cycle will also lead to cold buildings, as there would be no way to distinguish a real call for heat. If multiple facilities are in a company’s portfolio, it is very difficult to manually adjust the dead band when (for example) a winter storm is moving in. The M2G monitors the distribution loop every 10 seconds and automatically adjusts the firing cycle of each boiler without any human intervention.

Will it work on my boiler?

The M2G works on the majority of boiler makes and models that are used for space-heating. The chart below identifies which boiler systems we can improve:

Yes No
Closed-Loop Hot Water Boliers Steam Boilers
Boilers that experience normal cycling behavior Conventional domestic hot water heaters
Natural Gas, Propane, LPG, or Oil Electric Boilers
Single or multiple boiler configurations (one M2G per boiler) Boilers that don’t cycle (either run continuously or rarely)
Single Stage, Multi-Stage, or Modulating boilers RBI Boilers controlled on building return
Systems with or without existing temperature reset controls) Boilers that don’t cycle (either run continuously or rarely)
Systems with or without existing Building Management Systems (BMS) Boilers with greater than 15°F dead band

What does it take to install the M2G?

After system verification and purchase, Greffen employees or approved contractors will install the M2G on your boiler system. The installation itself takes about 3 hours, and does not require any breaking of water lines. Once installed, the unit does not require any maintenance and it will automatically learn any new changes to the system.

How will this interfere with my current controls?

The M2G will work in conjunction with your current controls. The M2G only uses data to dynamically assess whether to delay boiler firing based on system load. The signals and safeguards of the existing controller will continue to function normally.

How can I be sure this won’t prevent the boiler from operating properly?

We understand your concern about system reliability. The M2G was designed by boiler engineers and has various fail safe mechanisms to prevent boiler condensation and building comfort issues. If the M2G fails closed, any damage or malfunction to the M2G, and the boiler  system, will continue to run as if the M2G wasn’t there.

  • M2G will never turn off a running boiler.
  • M2G will never turn-on a boiler.
  • M2G never holds off boiler for longer than 15 minutes.
  • M2G never allows supply temperature to drop more than 14.4°F

Why would I need an M2G if I already have a Building Management System or Outdoor Temperature Reset?

The M2G works in conjunction with the BMS, and doesn’t interfere with the BMS in any way, other than to delay the firing of the boiler. A BMS rarely has the ability to dynamically control the boiler firing based on system conditions. The outdoor temperature reset is a very rough attempt to predict building load but will not reduce cycling at either set point.

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