ecoTEC plus 937 installation and maintenance manual
38
5.9
Checking the gas supply
5.9.1 Factory
settings
a
Caution!
Before operating the boiler check the type-plate
(data badge) underneath the appliance and
ensure that the correct gas type appliance has
been installed.
The combi boiler is supplied ready for operation and
additional settings are not required; the gas inlet
working pressure and the maximum gas rates should be
checked, however, in accordance with the information in
5.9.2 and 5.9.3.
5.9.2 Gas inlet working pressure
Check the gas inlet working pressure as follows:
Remove the front cover from the combi boiler.
• Close the gas isolation valve on the combi boiler.
1
2
Fig. 5.6 Checking the gas inlet working pressure
• Loosen the sealing screw on the gas valve marked
with (
1
) in the illustration.
• Connect a digital pressure gauge or U-tube
manometer (
2
).
• Open the gas isolation valve on the combi boiler.
• Start up the combi boiler (see the operating
instruction manual for the combi boiler).
• Read off the value from the U-tube manometer and
make sure that the gas pressure is between the
following values.
a
Natural gas:
DO NOT continue with the settings or start up
the unit if the supply pressure is not within the
range 17-25 mbar.
a
Liquid gas:
DO NOT continue with the settings or start up
the unit if the supply pressure is less than
37 mbar.
• Turn the unit off and remove the U-tube manometer.
• Tighten the test point screw and check for leaks.
• Record the inlet working pressure (mbar) in the
Benchmark gas boiler commissioning checklist.
5.9.3 Checking the gas rate
The combi boiler is equipped with a fully modulating
automatic gas valve which ensures that the correct air-
gas mixture is provided under all operating conditions.
The gas rate is set in the factory and need not be
adjusted subsequently.
With the front cover fitted, the gas rate of the combi
boiler is checked as follows:
• Activate the operating mode full load operation by
simultaneously pushing the buttons "
+
“ and "
–
“ on the
display (alternatively fully open the hot water tap).
• Wait at least 5 minutes or until the combi boiler has
reached its operating temperature.
• With all other gas appliances are switched off,
measure the gas rate on the gas meter. The gas rate
must correspond to the values given in Table 5.1.
a
Caution!
If the measured gas rate lies outside the
tolerance limits specified in Table 5.1, do not
operate the appliance and inform the Vaillant
Customer Service.
5 Commissioning, Part I 1
