25
Grant Vortex Outdoor Module
5 - BOILER INSTALLATION
1 Automatic air vent(s) are fitted to the top of the
boiler (see Figs. 8 and 16). Check that the small
cap on the top of each air vent is screwed on fully,
then unscrew it one complete turn - the cap remains
in this position from now on.
2 If the flexible filling loop is used to fill the system, ensure
it is connected and that the valve connecting it to the
system is open and the valve at the front is closed.
A valve is open when the operating lever is in line with
the valve, and closed when it is at right angles to it.
3 Ensure that the mains cold water supply valve is open
(operating lever in line with the valve), then turn on the
mains cold water supply and gradually open the front
valve on the filling loop until water is heard to flow.
4 Vent each radiator in turn, starting with the lowest
one in the system, to remove air.
5 It is important that the pump is properly vented to
avoid it running dry and damaging its bearings. To
gain access to the pump for venting it is necessary
to remove the top panel.
Remove the cap, then unscrew and remove the plug
from the centre of the pump. Using a suitable
screwdriver rotate the exposed spindle about one
turn. Replace the plug and cap.
6 Check the operation of the safety valve by turning
the head anticlockwise until it clicks. The click is
the safety valve head lifting off its seat allowing
water to escape from the system.
Check that this is actually happening.
7 Continue to fill the system until the pressure gauge
indicates 1.0 bar. Close the fill point valve and
check the system for water soundness, rectifying
where necessary. Water may be released from the
system by manually operating the safety valve until
the system design pressure is obtained.
8 The system design pressure (cold) should be
between 0.5 bar and 1.0 bar. The pressure is
equivalent to the maximum static head in bar + 0.3
(1 bar = 10.2 metres of water), where the static
head is the vertical height from the centre of the
expansion vessel to the highest point of the system.
9 Close the valves either side of the filling loop and
disconnect the loop.
The expansion vessel fitted is supplied with a
charge pressure of 1.0 bar (equivalent to a max.
static head of 10.2 metres). The charge pressure
must not be less than the actual static head at the
point of connection. Do not pressurise the vessel
above 1.5 bar.
The air pressure in the vessel must be checked annually.
The central heating system volume, using the
expansion vessel as supplied, must not exceed the
recommended volumes. If the system volume is
greater, an extra expansion vessel (complying with BS
4841) must be fitted as close as possible to the central
heating return connection on the boiler. The charge
pressure of the extra vessel must be the same as the
vessel fitted in the boiler. Refer to BS 7074:1 for
further guidance.
The air charge pressure may be checked using a tyre
pressure gauge on the expansion vessel Schraeder
valve. The vessel may be re-pressurised using a
suitable pump. When checking the air pressure the
water in the heating system must be cold and the
system pressure reduced to zero.
A simple test to check if the expansion vessel size is
adequate, is to fill the system cold to 1.0 bar, then fully
heat the system and if the pressure rises no more than
2.0 bar the vessel is adequate. A higher figure
indicates that an extra vessel is required.
See wiring diagrams in Section 9
Note: A test switch is fitted to the control panel to
allow the boiler to be test-fired. When On, the
switch by-passes the external control system.
1 Undo the three screws and remove the lefthand
cover from the control panel to gain access to the
boiler terminal block.
2 Pass the mains power supply cable through the
cable grommet in the control panel, through the
cable clamp and connect to the terminal block as
follows:-
Live (brown) to terminal 2 - marked permanent
live
Neutral (blue) to terminal 3 - marked mains
neutral
Earth (green/yellow) to terminal 4 - marked
mains earth
Fill the sealed system
5.6
Expansion vessel pressure
5.7
Connect the power supply
5.8
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