Viessmann Vitocrossal 300 CU3A, Service Instructions Manual, Page: 58 / 116

Vitocrossal 300 CU3A 26 to 199 Service
5673 649 - 18
58
Heating Circuit 1, 2 and 3
Coding 1
Select “Heating circuit ...”
Parameter address A5:... With heating circuit pump logic function: Heating circuit pump “OFF”
1 AT > RTset + 5 K
2 AT > RTset + 4 K
3 AT > RTset + 3 K
4 AT > RTset + 2 K
5 AT > RTset + 1 K
6 AT > RTset
7
to
15
AT > RTset - 1 K
AT > RTset - 9 K
Coding in the factory setting Possible change
Extended economy function adjusted outside temperature
A6:36 Extended economy function
disabled
A6:5
to
A6:35
Extended economy function
enabled, i.e. the burner and
heating circuit pump will stop
and the mixing valve close at
a variable value, adjustable
between 41°F and 95°F (5°C
and 35°C) plus 1.8°F (1°C). The
base value is the adjusted outside
temperature. This value is based
on the actual outside temperature
and a time constant, which takes
the cooling down of an average
building into consideration.
Coding in the factory setting Possible change
Priority DHW heating
A2:2 DHW tank priority applicable to
heating circuit pump and mixing
valve
A2:0 Without DHW tank priority
applied to heating circuit pump
and mixing valve.
A2:1 DHW tank priority only applicable
to mixing valve.
A2:3
to
A2:15
Reduced priority applied to mixing
valve (the heating circuit receives
a reduced amount of energy).
Economy function outside temperature
A5:5 With heating circuit pump logic
function (economy mode):
Heating circuit pump “OFF”
when the outside temperature
(AT) is 1 K higher than the set
room temperature (RTset)
AT > RTset + 1 K
A5:0 Without heating circuit pump
logic function.
A5:1
to
A5:15
With heating circuit pump logic
function: Heating circuit pump
“OFF”; see following table.