Danfoss ECL Comfort User Manual page 2

The shown diagram is a fundamental and simplified example and
does not contain all components that are necessary in a system.
If the system you are about to install differs from the shown
diagram of a standard heating system, feel free to sketch an outline
for comparison. Adaptation of systems, see section 10.
List of components:
ECL Comfort 300
S1 Compensation temperature sensor
S2 Room temperature sensor
S3 Flow / air duct temperature sensor
S4 Limitation temperature sensor
S6 Frost temperature sensor
P1 Fan
P2 Damper actuator
M1 Motorized control valve