Viessmann SCU224 User Manual page 27

SCU224
Maximum temperature limitation
MX3O / MX3F:
Maximum temperature limitation
Adjustment range:
30.0 ... 200.0 °F
[0.0 ... 95.0 °C]
in steps of 1 °Ra [0.5 K]
Factory setting:
MX3O: 140.0 °F [60.0 °C]
MX3F: 136.0 °F [58.0 °C]
Minimum temperature limitation
MN3O / MN3F:
Minimum temperature limitation
Adjustment range:
30.0 ... 190.0 °F
[0.0 ... 90.0 °C]
in steps of 1 °Ra [0.5 K]
Factory setting (Arr = 8 only):
MN3O: 140.0 °F [60.0 °C]
MN3F: 150.0 °F [65.0 °C]
Minimum and maximum temperature limits can be set for
the solid fuel boiler.
The maximum temperature limitation function provides a
maximum tem perature setting, usually to reduce scald risk
in a storage tank. If MX3O is exceeded, relay 2 is switched
off until the sensor falls below MX3F. TIn Arr 8, this func-
tion uses sensor 3 as reference sensor.
The minimum temperature limitation uses sensor 4 as
reference sensor.
The minimum temperature limitation function provides a
minimum tem perature setting for the solid fuel boiler in
system layout 8. If the temperature at sensor 4 falls below
MN3O, relay 2 is switched off until the temperature ex-
ceeds MN3F again.
Both switch-on and switch-off temperature differences
DT3O and DT3F are valid for the maximum and minimum
temperature limitation.
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