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 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.
See wiring diagrams in Section 12
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.
Combi 90 V3 and Combi MAX
1 Undo the three screws from the left hand cover on the
control panel to gain access to the boiler wiring terminal
block.
2 Pass the mains power supply cable through the cable
grommet into the control panel, through the cable clamp and
connect to the 7-way terminal block as follows:
Permanent Live (brown) to terminal 3 - marked L3 Neutral
(blue) to terminal 4 - marked N4 Earth (green/yellow) to
terminal 5 - marked E5
Condensing Combi
The Condensing Combi boilers are supplied fitted with an
electrical isolation plug - located in the left hand end of the
boiler control panel. All electrical wiring to the boiler
must
be
made to this plug.
1 Locate the plug, lift the retaining tab and pull the plug to the
left to remove it from the socket in the control panel.
2 Prise open the clips on either side of the plug and open the
top to access the five terminals.
3 Connect the electrical supply and heating/hot water controls
to the terminals in the isolating plug as follows:
Terminal 1 -
Heating on (from timeswitch, thermostat
or programmer)
Terminal 2 -
Hot water on (from programmer)
Terminal -
Earth
Terminal N -
Neutral
Terminal 3 -
Mains live (including permanent live for
frost thermostat)
6 - BOILER INSTALLATION
31
Outdoor Combi 90 V3, Combi Max and Condensing Combi
6.6
\
Connect the power supply
6.5
\
Expansion vessel pressure
To avoid the danger of dirt and foreign matter entering the
boiler the complete heating system should be thoroughly
flushed out - before the boiler is connected and then again
after the system has been heated and is still hot. This is
especially important where the boiler is used on an old
system.
For optimum performance after installation, this boiler and
its associated central heating system must be flushed in
accordance with the guidelines given in BS 7593:1992
'Treatment of water in domestic hot water central heating
systems'.
This must involve the use of a proprietary cleaner, such as
BetzDearborn's Sentinel X300 or X400, or Fernox Restorer.
Full instructions are supplied with the products, but for
immediate information, please contact BetzDearborn on 0
1514209563 or Fernox on 0179 9550811.
For Long term protection against corrosion and scale, after
flushing, it is recommended that an inhibitor such as
Betzdearborn's Sentinel X 100 or Fernox MB- 1 is dosed in
accordance with the guidelines given in BS 7593:1992.
Failure to implement the guidelines will invalidate the
warranty.
The air pressure in the vessel must be checked annually.
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.
IMPORTANT:
Pass the cable from the electrical power
supply and heating/hot water controls through the cable
clamp on the underside of the control panel
before
making
connections to the isolating plug.
Important: Ensure that the electrical supply as been
isolated before commencing.
Note:
The terminal numbers are marked on the top cover
of the plug.
