29
Installation and maintenance instructions ecoCRAFT 0020055744_08
• If you cannot correct the defects you must not start
up the boiler.
6.5.2 Checking the gas inlet working pressure
• Ensure that the gas inlet working pressure can be ob-
tained with all other gas appliances in the property
working.
• Remove the front casing from the boiler.
• Close gas isolation valve of the boiler.
1
Fig. 6.3 Measuring the gas inlet working pressure
• Loosen the sealing screw of the pressure measure-
ment nipple marked "in" (
1
) on the gas pipe (see Fig.
6.3).
• Connect a digital pressure gauge or U-tube manome-
ter (2).
• Open gas isolation valve of the boiler.
• Start the boiler by activating the test program P.1. as
described in section 9.4.
• In addition, ensure that maximum heat can be dissi-
pated into the heating system.
• 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 6.4.
Boiler
Natural Gas (G 20)
Minimum pres-
sure in mbar
Maximum pres-
sure in mbar
ecoCRAFT VKK 806/3-
2806/3 17 25
17
25
Table 6.4 Gas inlet working pressures at the reference test
point
• Should the pressure recorded at the reference test
point in the boiler be lower than indicated (table 6.4)
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 com-
pany or the Vaillant Service Solutions team and pro-
ceed as follows:
• Take the boiler out of operation by pressing the + and
i buttons simultaneously and turn down both thermo-
stat control knobs.
• Close the gas isolation valve of the boiler.
• Remove the pressure gauge and re-tighten the sealing
screw (1).
• Turn on gas at the gas isolation valve.
• Make sure that there is no leakage at the sealing
screw.
• Turn off gas at the gas isolation valve.
• Put the front casing back on.
• Turn off electrical supply to the boiler.
• You must not start up the boiler.
If the gas inlet working pressure is within the permissi-
ble range, proceed as follows:
• Take the boiler out of operation by pressing the + and
i buttons simultaneously and turn down both thermo-
stat control knobs.
• Close gas isolation valve of the boiler.
• Remove the pressure gauge and re-tighten the sealing
screw (1).
• Open the gas isolation valve of the boiler.
• Make sure that there is no leakage at the sealing bolt
screw.
• Put the front casing back on.
• Reset boiler controls for normal operation.
• Record the appliance gas inlet working pressure
(mbar) in the Benchmark gas boiler commissioning
checklist.
6.5.3 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.
Check the gas flow rate of the boiler as follows:
• Start the boiler by activating the test program P.1. as
described in section 9.4.
• In addition, ensure that maximum heat can be dissi-
pated into the heating system by.
• 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 6.5.
Boiler
Nominal net
heat input
in kW
Gas Rate
Natural Gas in m
3
/h
nominal
+5%
-10%
VKK GB 806/3-E-H
80
8.46
8.88
7.61
VKK GB 1206/3-E-H
115.9
12.25
12.86
11.03
VKK GB 1606/3-E-H
160
16.91
17.76
15.22
VKK GB 2006/3-E-H
200
21.14
22.2
19.03
VKK GB 2406/3-E-H
240
25.37
26.64
22.83
VKK GB 2806/3-E-H
280
29.59
31.97
26.63
Table 6.5 Gas rates (as per BS EN 483)
Start-up 6
