Gas Inlet Working Pressure; Main Burner Pressure - Vaillant TURBOmax VUW 242 E Instructions For Installation And Servicing

At this point the preset maximum
domestic hot water flow rate can be
adjusted if required.
Note: The water flow limiter built
into the boiler ensures that the
maximum domestic hot water flow
rate does not exceed the nominal
setting (equivalent to a hot water
temperature rise of 35°C).
Adjustment is only required if the user
requires a higher temperature rise
than this setting.
Turn the water flow adjusting screw
(1, fig. 35) clockwise to decrease the
flow from the tap until the temperature
rise is at the desired level. Turn off the
hot tap after completion of adjustment.

5.7 Gas inlet working pressure

Check the gas inlet working pressure
by slackening the sealing screw and
attaching a U gauge to the test point
(3, fig. 36) on the inlet to the gas valve.
Fire the boiler at full rate by opening
a hot water tap. Check that the U
gauge is reading 20 mbar.
(If the pressure is not 20mbar this
should be investigated before
continuing with the commissioning
procedure. Lower pressures than
20mbar are indicative of an incorrectly
sized or partially blocked gas supply).
Turn off the hot tap. Remove U gauge.
Tighten the test point screw and test
for soundness.

5.8 Main burner pressure

The burner pressure on this boiler has
been factory set and does not require
adjustment. The main burner pressure
may be checked in the following way:
•
Slacken the sealing screws and
attach one arm of a U gauge to the
burner test point (1, fig. 37).
Remove plastic sealing plug and
connect the other arm to the
combustion chamber sensing tube
(2, fig. 37).
•
Ensure the maximum hot water
temperature control (4, fig. 37) is
set to '9'.
•
Fully open a hot water tap to fire
the boiler at full rate.
Break the in line connector to the
NTC temperature sensor (3, fig.
37).
•
Check that the burner pressure is as
shown in Table 4. (If the burner
pressure is not correct within the
Supplied By www.heating spares.co Tel. 0161 620 6677
tolerance shown, contact Vaillant
Ltd. Technical Department).
•
Turn off the hot tap.
•
Remove U gauge. Tighten the sea-
ling screw (1, fig. 36)and test for
soundness. Reconnect NTC sensor
(3, fig. 37). Refit plastic plug in
chamber sensing tube.
•
Reset the maximum hot water
temperature selector to the required
setting (see Section 5.14).
•
Raise control box and secure in
position using screw (1, fig. 25).
Table 4: Burner Pressure & Gas Rate
Maximum Burner
Pressure (DHW)
Maximum Gas
Rate
fig. 35
fig. 36
fig. 37
VUW 242
10.0 mb
( - – + 1.0 mb)
2.79 m 3 /h
(98.5 ft 3 /h) (115.1 ft
VUW 282
10.6 mb
( - – + 1.0 mb)
3.26 m 3 /h
3 /h)
25