Design And Functions - Viessmann VITOCROSSAL 300 Technical Data Manual

Vitocrossal 300 CU3A 26 to 57 Technical Data

Design and Functions

Technical Data
Rated supply voltage:
Rated frequency:
Rated current:
Max. ambient temp.
- at operation:
- when storing
or transporting:
Max. operating temp.
setting (space heating):
DHW production:
Setting fixed high limit:
(not adjustable)
Adjustment range of
DHW tank set-point
temperature:
Heating curve settings
- Heating curve slope:
- Heating curve shift:
Room
set-point
temperature
Legend
A Low temperature heating system,
e.g. radiant floor heating
B Medium temperature heating system,
e.g. cast iron radiation, staple-up radiant floor heating
C High temperature heating system,
e.g. fintube radiation, fan coils
(continued)
120VAC
60 Hz
Less than 12 A
32 to 104ºF (0 to 40ºC)
Installation in living spaces or
boiler rooms (standard ambient
conditions)
-4 to +158ºF (-20 to +70ºC)
194ºF (90ºC)
194ºF (90ºC)
210ºF (99ºC)
50 to 149ºF (10 to 65ºC)
0.2 to 3.5
-12 to +33ºC
-13 to 40 K
Outdoor temperature
Heating Curve Adjustment (slope and shift)
The control unit regulates the boiler water temperature
(= supply temperature of heating circuit without mixing
valve) and the supply temperature of the heating circuit
with mixing valve (in conjunction with the accessory kit
for a heating circuit with mixing valve) according to the
outdoor temperature. The boiler water temperature is
automatically raised by 0 to 72 F / 0 to 40 K higher than
the currently required set supply temperature
(in the factory default setting the differential temperature
is 14.4 F / 8 K). See Service Instructions for coding
address "9F" in coding level 2.
The supply temperature that is required to achieve a
given room temperature depends on the heating system
and the thermal insulation of the building that is being
heated.
The adjustment of the two heating curves is used to
match the boiler water temperature and the supply
temperature to these conditions. The boiler water
temperature is limited upwards by the fixed high limit
and the temperature set for the electronic high limit.
The supply temperature cannot rise above the boiler
water temperature.
Boiler Control
11