Supply Pressure - Viessmann Vitocrossal CRU 800 Service Instructions For Contractors

Checking the static pressure and supply pressure
Static pressure
1. Close the gas shut-off valve.
2. Undo the screw in test connector
remove the screw.
3. Connect the pressure tester at test connector
4. Open the gas shut-off valve.

Supply pressure

1. Activate emissions test mode.
Vitotronic control unit operating instructions
2. Measure the supply pressure (flow pressure) at
rated heating output.
Natural gas E/LL
■ Set value: 17 to 25 mbar (1.7 to 2.5 kPa)
Nominal supply pressure: 20 mbar (2 kPa)
■
Note
■ The nominal supply pressure can differ from
these values subject to region; see type plate of
the burner.
■ The gas pressure switch on the gas train is set to
15 mbar (1.5 kPa).
i.e. the burner cannot be operated at a gas sup-
ply pressure below 15 mbar (1.5 kPa).
Note
Use a suitable measuring device with a resolution
of at least 0.1 mbar (0.01 kPa) to check the supply
pressure.
Supply pressure Measure
(flow pressure) nat-
ural gas E and LL
< 15 mbar Do not make any adjustments.
< 1.5 kPa Notify the gas supply utility.
15 to 17 mbar Please note: The boiler may only be operated temporarily with this setting (emergency
1.5 to 1.7 kPa mode).
Notify the gas supply utility.
5. Measure the static pressure: Max. 100 mbar
(10 kPa).
. Do not
A
Note
The max. static pressure corresponds to the max.
. permissible gas pressure at the burner to allow for
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safe commissioning of the appliance.
6. Record the actual value in the report.
3. Record the actual value in the report.
4. Switch off the ON/OFF switch at the programming
unit of the Vitotronic control unit.
5. Close the gas shut-off valve.
6. Remove pressure gauge. Close test connector
with the screw.
7. Open the gas shut-off valve. Start up the appli-
ance. Check gas tightness at test connector
Commissioning, inspection, maintenance
(cont.)
Danger
Gas escaping from the test connector leads
to a risk of explosion.
Check for gas tightness.
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