Viessmann D2RA, Installation Instructions For Contractors

Page: 94 / 164

94
Fault code dis-
played System characteristics Cause Measures
6A No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Fault in evaporator circuit
sensors 12 and 13
■
Check for air in the primary cir-
cuit and vent if required.
■
Check evaporator circuit sensors
12 and 13; replace if required.
6b No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Evaporator temperature
too low If natural heat source is geother-
mal energy via geothermal probe:
■
Ground temperature too low. No
action required
If natural heat source is solar ther-
mal:
■
Check mixing valve
6C No heating operation and no
DHW heating Low temperature process
pump fault Check low temperature process
pump cable and replace low tem-
perature process pump if necessa-
ry.
6D No heating operation and no
DHW heating High temperature process
pump fault Check high temperature process
pump cable and replace high tem-
perature process pump if necessa-
ry.
6E No heating operation and no
DHW heating Control valve fault Check control valve cable, motor
and ball valve, and replace if nec-
essary.
70 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Short circuit, evaporator
inlet temperature sensor Replace evaporator inlet tempera-
ture sensor (for location, see
page 103)
71 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Lead break, evaporator in-
let temperature sensor Replace evaporator inlet tempera-
ture sensor (for location, see
page 103)
72 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Short circuit, evaporator
outlet temperature sensor Replace evaporator outlet temper-
ature sensor (for location, see
page 103)
73 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Lead break, evaporator
outlet temperature sensor Replace evaporator outlet temper-
ature sensor (for location, see
page 103)
74 No heating operation and no
DHW heating Short circuit, heat ex-
changer temperature sen-
sor Replace heat exchanger tempera-
ture sensor.
75 No heating operation and no
DHW heating Lead break, heat ex-
changer temperature sen-
sor Replace heat exchanger tempera-
ture sensor.
76 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Short circuit, sorber outlet
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).
77 No sorption operation; heat-
ing operation and DHW heat-
ing only in condensing mode Lead break, sorber outlet
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).
Troubleshooting
Fault codes
(cont.)
5678 044 GB
Diagnosis