Fig. 57
39
7.22
TO REMOVE/REPLACE THE CENTRAL
HEATING EXPANSION VESSEL (fig. 57).
In the unlikely event of failure of the central
heating expansion vessel it is recommended
a suitable expansion vessel be fitted
external to the boiler. It should be positioned
on the return pipe and as close to the boiler as
possible. However, if it is necessary to replace
the central heating expansion vessel the
boiler must be removed from the wall as
follows.
7.22.1
Remove the casing (sect. 7.3) and lower the
instrument panel and remove the control box
cover.
7.22.2
Close the on/off valve on the central heating
and gas supply, and drain the boiler.
7.22.3
Disconnect all pipework connected to boiler.
7.22.4
Disconnect mains cables and any other
connections (room thermostat, programming
clock).
7.22.5
Remove the duct an remove the 2 top coach
bolts then remove the boiler by lifting from
the wall bracket.
7.22.6
Unscrew the nut that connects the expansion
vessel and remove it.
7.22.7
Remove the screw and the bracket supporting
expansion vassel.
7.22.8
Replce in reverse order.
7.22.9
Remove the expansion vessel.
7.22.10
Replace all the components in reverse order
using new seals.
7.22.11
Fill the system as described in the sect. 6 and
check for leaks.
7.23
TO REMOVE/REPLACE TIMECLOCK
(Fig.88/A)
.
7.23.1
Remove the front panel from the outer casing
(sect. 7.3) and lower the instrument panel.
7.23.2
Remove control box cover (Sect. 7.19).
7.23.3
Remove control board (Sect. 7.19) from
panel.
7.23.4
Remove two clips securing the timer.
7.23.5
Carefully remove the wires connecting
timer.
7.23.6
Replace in reverse order (ensure all
electrical connections are made correctly)
(Fig.
59).
Fig. 58
7.24
EXTERNAL HEATING CONTROLS (Fig.58).
7.24.1
Remove front and bottom of the casing
(sect7.3).
7.24.2
Remove the external wire link on the PCB
box.
7.24.3
Replace with external wire controls.
Summary of Contents for 780 Series
Page 2: ......
Page 7: ...7 Fig 3 OVERALL DIMENSION ...
Page 34: ...34 Fig 45 Fig 44 Fig 46 ...
Page 36: ...36 Fig 48 Fig 47 Fig 49 Fig 50 Fig 51 ...
Page 42: ...Fig 59 42 SECTION 9 ELECTRICAL SYSTEM DIAGRAM ...
Page 46: ...79 83 105 46 50 27 16 39 17 2 22 100 1 4 5 11 8 SECTION 11 ...
Page 49: ...49 ...
Page 50: ...COD 0017LIB06010 2 03 2010 ...