Viessmann C3TB, Installation And Service Instructions For Contractors

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Supply pressure (flow pressure) Steps
Below 17.4 mbar (1.74 kPa) Do not commission the appliance. Notify your gas supply utility.
17.4 to 25 mbar (1.74 to 2.5 kPa) Commission the appliance.
Above 25 mbar (2.5 kPa) Connect the separate gas pressure governor upstream of the system and
set the pre-charge pressure to 20 mbar (2.0 kPa). Notify your gas supply
utility.
Function sequence and possible faults (gas condensing module)
Display Measure
Control unit issues a heat
demand
No
Increase set value and en-
sure heat is drawn off
Yes
Fan starts No
After approx. 51 s fault F9 Check the fan, fan connect-
ing cables, power at the fan
and fan control
Yes
Ignition No
Fault EE Check ignition module (con-
trol voltage 230 V across
plugs "X2.1" and "X2.2").
Check the gas supply.
Yes
Gas train opens No Fault EE Check the gas train (control
voltage 230 V
∼
); check the
gas supply pressure.
Yes
Ionisation current builds
Symbol
A
No
Fault EE Check setting of ionisation
electrode.
Purge the gas line.
Yes
Burner in operation No Shuts down below the set
boiler water temperature and
restarts immediately Check the flue system for
tightness (flue gas recircula-
tion); check the gas flow
pressure.
Commissioning, inspection, maintenance
Checking the static pressure and supply pressure
(cont.)
5775 636 GB