Viessmann D2RA, Installation Instructions For Contractors

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100
Fault code dis-
played System characteristics Cause Measures
EF Burner in a fault state Flame is lost immediately
after it has built (during
safety time). Check gas supply (gas pressure
and gas flow switch).
Check balanced flue system for
flue gas recirculation.
Check ionisation electrode (replace
if required):
■
Distance to burner gauze assem-
bly (see page 52)
■
Electrode contamination
Press reset button R .
F0 Burner blocked Internal fault Replace control unit.
F1 Burner in a fault state Flue gas temperature lim-
iter has responded. Check fill level in secondary circuit.
Vent the system.
Press reset button
R after flue sys-
tem has cooled down.
F2 Burner in a fault state Temperature limiter has
responded. Check heating system fill level.
Check circulation pump. Vent the
system. Check secondary circuit
temperature limiter and connecting
cables. Check high limit safety cut-
out and connecting cables, and re-
set if necessary.
Press reset button
R .
F3 Burner in a fault state Flame signal is already
present at burner start. Check ionisation electrode and
connecting lead.
Press reset button
R .
F7 Burner blocked Short circuit or lead break,
water pressure sensor Check the water pressure sensor
and lead.
F8 Burner in a fault state Fuel valve closes too late. Check gas train. Check both con-
trol paths.
Press reset button
R .
F9 Burner in a fault state Fan speed too low during
burner start Check fan, fan connecting cables
and power supply to fan; check fan
control.
Press reset button
R .
FA Burner in a fault state Fan idle state not reached Check fan, fan connecting cables
and fan control.
Press reset button
R .
FC Burner in a fault state
■
Gas train faulty
■
Faulty fan control
■
Faulty modulation valve
control
■
Flue gas path blocked
Check gas train. Check flue sys-
tem.
Press reset button
R .
Fd Burner in a fault state and ad-
ditional fault b7 is displayed. Coding card missing. Insert coding card.
Press reset button
R .
Replace control unit if fault per-
sists.
Troubleshooting
Fault codes
(cont.)
5678 044 GB
Diagnosis