Diagnostics - Viessmann MatriX Service Instructions Manual

Diagnostics

Faults indicated at the display and programming unit
General process fault
Fault System
code characteristics
20 Fan pressure
produced during air
pressure limiter idle
state check
Air pressure limiter
not functioning
properly
21 Air pressure limiter
shows no air
pressure, fan does
not operate
Fan not running
22 Gas governor shows
no gas pressure
during the safety
period
25
No flame notified
after the safety
period, ionisation period, ionisation
flame monitor
shows no flame
signal
Cause
Wind influence on
fan
Air pressure limiter
faulty
Air pressure limiter
faulty
Fan faulty, cables
faulty or broken
Gas shut−off valve
closed, gas
governor faulty
Ionisation electrode
incorrectly adjusted
Ignition electrodes
incorrectly adjusted
Insulation body of
ignition electrodes
broken
Incorrect gas type
selected
Gas combination
valve does not open
Combustion
characteristics not
ideal
Incorrect parameter
set selected
Troubleshooting
Remedy
Check flue gas draught
(chimney)
Replace air pressure
limiter
Replace air pressure
limiter
Check cables and replace
fan, if necessary
Open gas shut−off valve,
check gas supply
pressure and clean gas
filter, if necessary
Adjust ionisation
electrode (see page 18)
Adjust ignition
electrodes (see page 18)
Replace ignition
electrodes
Adjust gas type
(see pages 6 and 7)
Check gas combination
valve and replace, if
necessary
Adjust burner
(see pages 14 and 15)
Adjust parameter set
(see pages 28 and 30)
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