Technical data
10
CTC EcoZenith i250 
General Information
Examples of Heating Curves
You can see in the diagram below how the heating curve 
changes with different Inclination settings. The gradient of 
the curve shows the temperatures that the radiators require 
at different outdoor temperatures.
Curve Inclination
The inclination value which is set is the primary flow 
temperature when the outside temperature is –15°C.
Primary Flow Temperature
Primary Flow Temperature
Primary Flow Temperature
Primary Flow Temperature
Outside Temperature
Outside Temperature
Outside Temperature
Heating off, out
Heating off, out
Heating off, out
Outside Temperature
Adjustment
The curve can be parallel displaced (adjusted) by the 
desired number of degrees to adapt to different systems/
houses.
An example
Inclination 60°C
Adjustment 0°C
In this example, the maximum outgoing primary flow 
temperature is set at 55°C.
The minimum permitted primary flow temperature is 27°C 
(e.g. summer-time basement heating or the floor circuits in 
a bathroom).
Summer-time operation
All properties have internal heat gains (lamps, oven, 
personal heat etc.), which means that the heating can be 
switched off when the outdoor temperature is lower than 
the desired room temperature. The better insulated the 
house is, the earlier the heating from the heat pump can be 
switched off.
The example shows the product set at the default value of 
18°C. This Heating off value can be changed under the 
Installer/Settings/Radiator system menu. 
When the heat is switched off in this way, the radiator 
pump stops and the mixing valve is shut down. The heating 
starts up automatically when it is required again.
Inclination 50°C 
Adjustment +5°C
Inclination 50°C 
Adjustment 0°C










