Gas Inlet Working Pressure; Adjusting Central Heating Output (Range Rating) - Vaillant ECOmax VUW 236 EH Instructions For Installation And Servicing

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
(2, fig. 38) 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.

5.8 Gas inlet working pressure

(fig. 39)
Check the gas inlet working pressure
by slackening the sealing screw and
attaching a U gauge to the inlet test
point on the gas valve marked `PE'.
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 con-
tinuing with the commissioning pro-
cedure. 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.
5.9 Adjusting the central
heating output
(range rating)
ECOmax is fully modulating for
central heating, and it is therefore not
necessary to range rate the central
heating. The boiler operates at very
high efficiency across its heat output
range. However, even greater
efficiency may be obtained by range
rating the boiler, as follows:-
•
Put the boiler into diagnostic mode
by pushing the two buttons below
the boiler display simultaneously
until a `d' code is displayed
(1 and 2, fig. 40).
(For further information on how to
use the boiler display refer to
Section 8: Fault Finding)
•
If code `d. 0' is not displayed, push
the left hand button to step through
the various D codes until the screen
shows the `d. 0' code
28
fig. 38
fig. 39
fig. 40