Danfoss RET 230 HCW-1 Installation Instructions Manual page 8

DIL Switch descriptions
Switch 4: If set to On/Off, both heating and cooling operates
Switch 3: Active only if switch 4 is set to Chrono. This
Switch 2: Allows Celsius or Fahrenheit temperature scaling
Switch 1: Not used in this model.
8
in on/off mode. If set to Chrono, both heating and
cooling operates in chrono-proportional mode.
switch determines the number of cycles per hour
that the thermostat will impose on the system,
the options are three 20 minute cycles or six 10
minute cycles.
to be selected.