→DI exp 1 DI1 Exp1:
NO/NC: NC Signal:
Ext alarm1 Status:Off
Overheat pre-heater is presented in the display when
the alarm is active.
→AO exp1 AO1 Exp1:
Sign: Extra unit Auto
Value: 0,0 V
Control signal for heater 0-10V
→DO exp1 DO1 Exp1:
Sign: ExtraUnitActi Auto
Status: Off
Activated during defrosting sequence.
→Extra control unit Mode extra unit Run if
defrosting
Activated during defrosting sequence.
See Example 1
Mode extra unit Run if units
us running
Activated during normal run.
See Example 2
Option: Running if unit is running is to avoid defrosting
if unbalanced airflow is not permitted.
Control mode extra unit
Heating
→Settings →Control extra unit Control extra unit P-band:
33.0 °C
I-time: 100.0 s
Set P-band and I-time for Control extra unit.
→Temperature Extra unit Actual: NaN
°C Setp: 18.0 °C
Set the pre-heater temperature
Example 1
Run if defrosting. If pre-heater is used in order to maintain supply temperature at correct level.
For example, correct supply temperature is +20 °C, the outside air is -4 °C and the heater has an capacity of 10 °C. This is
enough during normal operation on these units but during bypass defrosting the heater needs a capacity of 24 K. This is a de-
ficiency by 14 K.
In this example a set point for the pre-heater needs to be +10 °. Set point must be chosen according to heat capacity and
airflow.
Example 2
Run if units is running. In this case you need to have a set point at 0 °C.
Pre-heater will be active below 0 °C during normal operation. To use this option configuration must be changed. Same extra
sensor as above is used.
It can also be used for a unit in a very cold location when the heating capacity is not enough. For example -30 °C. Set point
depending of heat capacity and airflow. In this case a set point can be, for example -18 °C.
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