Viessmann Vitocal 350-A Installation And Service Instructions Manual page 153

Control unit diagnostics
Display system of information and
fault index
Four different messages are possible at
each position in the information index
and fault index. The control unit displays
these messages with the codes 1, 2, 4
and 8. If several messages are active
simultaneously, the relevant codes are
added hexadecimally. Hexadecimal
totals are unique, i.e. the individual
active codes can be determined accord-
ing to the following table.
Active codes C
Display value
"0"
"1"
"2"
"3"
"4"
"5"
"6"
"7"
"8"
"9"
"A" (≙10)
"B" (≙11)
"C" (≙12)
"D" (≙13)
"E" (≙14)
"F" (≙15)
Information index "I" I
Position Code
Most recent commands transferred from the heat pump control unit to the EEV con-
troller
1 4
(cont.)
Active codes
1 2 4 8
X
X
X X
X
X X
X X
X X X
X
X X
X X
X X X
X X
X X X
X X X
X X X X
Explanation
Message received regarding EEV controller restart
How to analyse the information index
and fault index
1. Check the display value for each posi-
tion individually.
2. Determine active codes C from the
table.
3. See tables E and I for explana-
tions of active codes.
Troubleshooting
153