What is load/modulation control?

The HubR uses a modulation algorithm to effectively modulate the boiler demand in order to work with the thermal inertia of the system. 

For example, a Gas system, the modulation algorithm uses 6 x 10 minute time periods per hour to determine whether the boiler should be on or off, based on the temperature difference between the set point and the measured value (from the Radiator or Room thermostats).   

For a cold room, the first 10 minute period is driven at 100%, and so the boiler is on for the full 10 minutes.  The second 10 minute period may only have a demand of 60%, and so the boiler is only switched on for 6 minutes, then off for 4 minutes.  The third period is say 30% demand, so the boiler is only on for the first 3 minutes and off for 7 minutes.  The Hub LED only comes on when the relay turns the boiler on. 

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There are 3 fuel types available for boiler control:

• Gas will fire up to 6 times an hour - so once every 10 minutes: 6 x 10= 60 minutes 
• Oil will fire up to 3 times an hour - so once every 20 minutes: 3 x 20= 60 minutes 
• Electricity will fire up to 10 times an hour - so once every 6 minutes: 10 x 6= 60 minutes