Checking The Gas Flow Rate; Checking The Gas Inlet Working Pressure - Vaillant ecoTEC VU 656/4 Installation And Maintenance Instructions Manual

6 Start-up

6.3.2 Checking the gas flow rate

The boiler is fitted with a multifunctional automatic gas
valve which ensures that the precise air/gas ratio is
provided under all operating conditions. The gas flow
rate has been set during production and does not
require adjustment. With the front casing fitted check
the gas flow rate of the boiler as follows:
• Start the boiler by activating the test program P.1 as
described in section 9.2.
• In addition, ensure that maximum heat can be
dissipated into the heating system by turning up the
room thermostat.
• Wait at least 5 minutes until the boiler has reached its
operating temperature.
• Ensure that all other gas appliances in the property
are turned off.
• Measure the gas flow rate at the gas meter.
• Check that the gas flow rate is as stated in Table 6.1.
Appliance
Maximum net heat input in kW
Gas flow rate
3
Natural gas in m /h
Table 6.1 Gas flow rate
• If the measured gas flow rate lies outside the
tolerance limits specified in Table 6.1, do not operate
the boiler and inform the Vaillant Service Solutions
(0870 6060 777).
If the measured gas flow rate is within the tolerance
limits shown in Table 6.1, then proceed as follows:
• Take the boiler out of operation by
- Pressing the + and i buttons simultaneously and
turn down both thermostat control knobs.
• Record the boiler maximum gas flow rate onto the
Benchmark gas boiler commissioning checklist.
6.3.3

Checking the gas inlet working pressure

• Ensure that the gas inlet working pressure can be
obtained with all other gas appliances in the property
working.
• Remove the front casing from the boiler.
• Close the gas isolation valve of the boiler.
28
ecoTEC VU 656
65
nom. + 5 % – 10 %
6,9 7,25 6,2
1
2
Fig. 6.5 Measuring the gas inlet working pressure
• Loosen the sealing screw marked "in" (1) on the gas
valve.
• Connect a digital pressure gauge or U-tube
manometer (2).
• Open the gas isolation valve of the boiler.
• Start the boiler by activating the test program P.1 as
described in section 9.2.
• In addition, ensure that maximum heat can be
dissipated into the heating system by turning up the
room thermostat.
• With the boiler operating at full load check that the
gas inlet working pressure at the reference test point
(1) complies with the requirements of Table 6.2.
Natural gas (G20)
Minimum
pressure at reference test
point in mbar
17
Table 6.2 Gas inlet working pressure at the reference test
point
• Should the pressure recorded at the reference test
point in the boiler be lower than indicated (Table 6.2)
check if there is any blockage in the pipework or if the
pipework is undersized.
• If the supply pressure is out of tolerance contact your
Emergency Service Provider.
If the gas inlet working pressure at the reference test
point (1) is not within the permissible range and you
cannot correct the failure, notify the gas supply
company or the Vaillant Service Solutions team and
proceed as follows:
• Take the boiler out of operation by
- Pressing the + and i buttons simultaneously and
turn down both thermostat control knobs.
• Close the gas isolation valve of the boiler.
Installation and maintenance instructions ecoTEC 0020029173_01
Maximum
pressure at reference test
point in mbar
25