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

Troubleshooting

Function sequence and possible faults

Control unit issues
a heat demand
Yes
Ignition
Yes
Gas train opens
Yes
Ionisation current
builds (higher than
2µA)
Symbol A
Yes
Burner in opera-
tion
32
Display
No Fault "F4"
No
Fault "F4"
No
Fault "F4"
No
Stops below the set
boiler water tem-
perature and re-
starts immediately
No
Measure
Increase set value
and ensure heat is
drawn off
Check the ignition
module connec-
tion
Check the gas
train (control volt-
age 230 V); check
the gas supply
pressure
Check the ionisa-
tion current, check
the electrode ad-
justment and the
gas line for air-
locks.
Check the flue sys-
tem for tightness
(flue gas recircula-
tion), check the
gas flow pressure