©
Viessmann 5443202
|
20
SCU124
∆
T-regulation
DT O:
Switch-on temperature diff.
Adjustment range: 2.0 ... 40.0°Ra
[1.0 ... 20.0 K]
in steps of 1 °Ra [0.5 K]
Factory setting: 12.0°Ra
[6.0 K]
DT F:
Switch-off temperature diff.
Adjustment range: 1.0 ... 39.0°Ra
[0.5 ... 19.5 K]
in steps of 1 °Ra [0.5 K]
Factory setting: 8.0°Ra
[4.0 K]
The controller works as a standard differential controller. If
the switch-on difference is reached, the pump is activated.
When the temperature difference falls below the adjusted
switch-off temperature difference, the relay switches off.
Note:
The switch-on temperature difference must be
at least 1 °Ra [0.5 K] higher than the switch-off
tempe rature difference.
DT S:
Nominal temperature difference
Adjustment range: 3.0 ... 60.0 °Ra
[1.5 ... 30.0 K]
in steps of 1 °Ra [0.5 K]
Factory setting: 20.0 °Ra
[10.0 K]
RIS:
Rise
Adjustment range:
2 ... 40 °Ra
[1 ... 20 K]
in steps of 2 °Ra [1 K]
Factory setting: 4 °Ra [2 K]
Pump speed control
A relative minimum pump speed can be allocated to the
output R1 via the adjustment channel nMN.
nMN:
Pump speed control
Adjustment range:
30 ... 100
in steps of 5 %
Factory setting: 30
Note:
When a load which is not speed-controlled is
used, the value must be set to 100 % in order to
deactivate pump speed control.
Minimum pump speed
When the switch-on temperature difference is reached,
the pump is activated at full speed for 10 seconds. Then, the
speed is reduced to the minimum pump speed value (factory
setting = 30 %).
If the temperature difference reaches the adjusted nominal
temperature difference, the pump speed increases by one
step (10 %). If the difference increases by the adjustable rise
value, the pump speed increases by 10 % respectively until the
maximum pump speed of 100 % is reached. The response of
the controller can be adapted via the parameter “Rise”.
Note:
The nominal temperature difference must be
at least 1 °Ra [0.5 K] higher than the switch-on
tempe rature difference.
4.2 Adjustment channels
Note:
For pump speed control, the operation mode of
relay 1 must be set to Auto (adjustment channel
MAN1)
System layout selection
Arr:
System layout selection.
Adjustment range: 1 ... 3
Factory setting: 1
In this channel, a pre-defined system layout can be selected.
Each system layout has a set of pre-programmed settings
that can be individually changed.
If the system layout selection is changed later on, all adjust-
ments made in the other channels will be lost. Therefore,
changing the system layout is always followed by a security
enquiry.
Only confirm the security enquiry if you are sure that
you wish to change the system layout selection!
Note:
When the drainback option ODB is activated,
the temperature differences DT O, DT F and
DT S are set to a fixed adjustment:
DT O
=
20 °Ra [10 K]
DT F
=
8 °Ra
[4 K]
DT S
=
30 °Ra [15 K]
Previous adjustments made in these channels will
be overridden and may have to be entered again if
ODB is deactivated later on.
Security enquiry:
Î
To confirm the security enquiry, press button 3
