56
Return preheating
the return preheating function can be used for
transferring heat from a heat source to the heating
circuit return.
the allocated relay is energised when both switch-
on conditions are fulfilled:
• the temperature difference between the allocated
sensors has exceeded the switch-on temperature
difference
• the temperature at the outdoor temperature
sensor has fallen below the adjusted outdoor
temperature
With the summer switch-off option, the return pre-
heating can be suppressed outside the heating pe-
riod. If the heating circuit concerned is controlled by
the controller, the adjustments automatically adapt
to the heating circuit.
Sensor HS
Relay
Sensor
Return
adjustment chan-
nel
Description
adjustment range / selection Factory setting
relay
relay selection
system dependent
system dependent
sen. return
return sensor selection
system dependent
system dependent
sen. Hs
Heat source sensor selection
system dependent
system dependent
∆
ton
switch-on temperature difference 2.0 ... 30.0 K [4.0 ... 60.0 °ra]
6.0 K [12.0 °ra]
∆
toff
switch-off temperature difference 1.0 ... 29.0 K [2.0 ... 58.0 °ra]
4.0 K [8.0 °ra]
summer off
summer switch-off option
Yes, no
no
sensor
outdoor sensor selection
system dependent
system dependent*
toff
switch-off temperature
10 ... 60 °C [50 ... 140 °F]
20 °C [68 °F]
Funct.
activation / Deactivation
activ., Deactivated
Deactivated
Arrangement / Opt. functions / Add new function... / Ret. preheat.
* When a heating circuit has been activated, this
adjustment is determined by the corresponding
parameter in the heating circuit menu.
295931-36390-8667 SOM 8 plus_en.indb 56
20.10.2011 13:14:48