Filling The Heating System; Initial System Flush ('Cold') - Vaillant ECOmax VUW 236 EH Instructions For Installation And Servicing

5.4 Filling the heating system

The boiler primary circuit and the hea-
ting system should be filled using a fil-
ling method as described in Section
3.7.2.
Ensure that the boiler CH service
valves (3, fig. 34) are open.
Partially open the filling valve and
allow water to enter the system. Star-
ting with the lowest radiator, open the
radiator air release until water (clear
of bubbles) is emitted.
fig. 35
Repeat this at all radiators until the
complete system is full, all air locks
have been cleared and the boiler
pressure gauge reads 1.5 Bar.
Release any air from the pump by
slackening the centre screw (3, fig.
35).
The boiler is equipped with an auto-
matic air release valve. To allow this
to vent the boiler, the cap on top (2,
fig. 35) must be slackened by 1-2
turns. (This cap must be left slackened
during boiler operation to ensure any
residual air or system gases are re-
leased).
Check the heating system and boiler
connections are sound.

5.5 Initial system flush ('cold')

The whole of the heating system must
be flushed out at least twice: once
cold, and once hot as instructed later
in Section 5.13.
Open all radiator or heating valves
and boiler CH service valves and
drain the heating system and boiler
completely from the lowest points of
1
the system via / " BSP drain taps
2
(opened full bore to remove any instal-
lation debris prior to lighting the boi-
ler).
Refill the heating system as described
in Section 5.4: Filling the heating
system.
Check the operation of the pressure
relief valve by rotating the knob on
the valve.
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