Temperature Compensation

The amount of heat required from the boiler will normally depend on the outside temperature. The lower the external temperature, the greater will be the leakage through the walls and windows.
While the room thermostat will control the maximum room temperature it is advantageous to control the circulating water temperature so that the water becomes hotter when the outside temperature falls. This enables a smoother control of the living environment.
The Multizoner II C has two controls to optimize the control. The SLOPE controls how the water temperature changes as the outside temperature changes. With a slope of 1 a decrease of outside temperature of 10C will result in an increase of water temperature of 10C. The slope may be increased to 3 and reduced to 0.2. In this latter case for example a decrease of outside temperature of 10 C will increase the water temperature by 2 C.

In general a radiator will require a greater slope than UFH as can be seen on the control legend. The greater the heat leakage (e.g. a conservatory) in the system the greater will be the slope required to control the heating effectively. The SHIFT controls the required water temperature for a given outside temperature. The control can vary the water temperature by approximately a constant -10 to +15 0C