Viessmann D2RA, Installation Instructions For Contractors

Page: 95 / 164

95
Fault code dis-
played System characteristics Cause Measures
78 No heating operation and no
DHW heating Short circuit, process cir-
cuit flow temperature sen-
sor Replace sorber outlet temperature
sensor, plus process circuit flow
and return temperature sensors.
Start sensor calibration manually
(code "16:1" in the
"Process"
group).
79 No heating operation and no
DHW heating Lead break, process cir-
cuit flow temperature sen-
sor Replace sorber outlet temperature
sensor, plus process circuit flow
and return temperature sensors.
Start sensor calibration manually
(code "16:1" in the
"Process"
group).
7A No heating operation and no
DHW heating Short circuit, process cir-
cuit return temperature
sensor Replace sorber outlet temperature
sensor, plus process circuit flow
and return temperature sensors.
Start sensor calibration manually
(code "16:1" in the
"Process"
group).
7B No heating operation and no
DHW heating Lead break, process cir-
cuit return temperature
sensor Replace sorber outlet temperature
sensor, plus process circuit flow
and return temperature sensors.
Start sensor calibration manually
(code "16:1" in the
"Process"
group).
90 Control mode Short circuit, temperature
sensor
/
Check sensor
/
on solar control
module.
91 Control mode Short circuit, temperature
sensor
aÖ
Check sensor
aÖ
on solar control
module.
92 No solar DHW heating and, if
natural heat source is solar
thermal, no sorption opera-
tion Short circuit, collector
temperature sensor Check temperature sensor & on
the solar control module or temper-
ature sensor on the Vitosolic.
93 Control mode Short circuit, cylinder tem-
perature sensor Check temperature sensor at ter-
minal S3 on the Vitosolic 100.
94 No solar DHW heating and, if
natural heat source is solar
thermal, no sorption opera-
tion Short circuit, cylinder tem-
perature sensor Check temperature sensor
%
on
the solar control module or temper-
ature sensor on the Vitosolic.
98 Control mode Lead break, temperature
sensor
/
Check temperature sensor
/
on
the solar control module.
99 Control mode Lead break, temperature
sensor
aÖ
Check sensor
aÖ
on solar control
module.
9A No solar DHW heating and, if
natural heat source is solar
thermal, no sorption opera-
tion Lead break, collector tem-
perature sensor Check temperature sensor
&
on
solar control module or sensor on
the Vitosolic.
9b Control mode Lead break, cylinder tem-
perature sensor Check temperature sensor at ter-
minal S3 on the Vitosolic 100.
9C No solar DHW heating and, if
natural heat source is solar
thermal, no sorption opera-
tion Lead break, cylinder tem-
perature sensor Check temperature sensor % on
the solar control module or temper-
ature sensor on the Vitosolic.
Troubleshooting
Fault codes
(cont.)
5678 044 GB
Diagnosis