Danfoss C67, User Manual

Page: 55 / 84

The grey
side of the
ECL Card
Ex
tended ser
vic
e
Service parameter(s) 35
32i
35 Return temperature influence - max. limitation
Circuit Setting range Factory setting
(I) / (II) -9.9 ... 0 ... 9.9 (-2.0) / (-2.0)
Set the influence from the return temperature on the desired flow
temperature.
Set the influence of the max. return temperature
limitation (set in line 30 or lines 31-34).
Influence higher than 0:
The desired flow temperature is increased, when
the return temperature gets higher than the set
limit.
Influence lower than 0:
The desired flow temperature is decreased, when
the return temperature gets higher than the set
limit.
0
Influence
Max. limitation > 0
Return limit
Return temp.
Max. limitation < 0
Example
The return limit is active from 50 °C.
The influence is set to -2.0.
The actual return temperature is 2 degrees too high.
Result:
The desired flow temperature is changed by -2.0 x 2 = -4 degrees.
Normally, the setting in line 35 is lower than 0 in district heating
systems to avoid a too high return temperature.
Typically, the setting in line 35 is 0 in boiler systems because a
higher return temperature is acceptable (see also line 36).