Function Sequence And Possible Faults - Viessmann Vitopend 100-W Installation And Service Instructions Manual

Function sequence and possible faults

Control unit issues
a heat demand
Yes
Fan starts
Yes
Ignition
Yes
Gas train opens
Yes
Ionisation current
builds (higher than
2 µA)
Symbol A
Display
No
No After approx. 51 s
fault "F5"
No
Fault "F4"
No Fault "F4"
No
Fault "F4"
Troubleshooting
Action
Increase set value
and ensure heat is
drawn off
Check the air pres-
sure switch, fan,
fan connecting ca-
bles and power at
the fan
Check the ignition
module connec-
tion
Check the gas
train (control volt-
age 230 V) and
gas supply pres-
sure
Check the ionisa-
tion current, check
the electrode ad-
justment and the
gas line for air-
locks.
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