Product specifications

The ¼ turn gas tap provided must be fitted in the
supply immediately before the boiler to enable
complete gas isolation to the boiler during
maintenance and servicing work.
To prevent the ingress of foreign matter and
possible damage to the gas-regulating block, the
gas supply pipe must be checked for contaminants
prior to connection to the boiler.
On final connection of the gas supply to the boiler,
the complete gas installation, including the meter,
must be tested for gas soundness and purged as
described in BS6891.
7.12. Connecting the condensate siphon
The connector for the condensate water discharge
is located on the underside of the appliance (C).
(Fig. 22).
Figure 22: Condensate connection.
Locate and connect the supplied siphon to the
boiler’s condensate drain connection via 32mm dia
plastic pipe.
For condensate drainage pipework, refer to Section
6.5 of these instructions.
7.13. Connecting the electrical supply.
All electrical connections to the mains supply must
be made in full accordance with the current I.E.E.
regulations.
The boiler must be earthed and connected via a
double pole isolating switch fused to 3 amp or
alternatively, by the use of a 3 amp fused three pin
plug and unswitched shuttered socket outlet.
Where possible, it is recommended that the
appliance is protected against electrical surges by
the fitting of an anti-surge device.
It is essential that the Live and Neutral connections
are the correct way round. If they are reversed, the
control unit will lock and a malfunction alert ‘L’
will be displayed on the control panel. Should this
occur, the wiring must be reversed to its correct
state and the boiler re-started.
The terminal block for the connection for a volt
free room thermostat, or time clock, is located
behind the control unit. The terminals are wired to
the input circuit of the control unit, which has its
own ‘wetting voltage’.
Important Note!
Under no circumstances must any electrical
power be input to the room thermostat
erminals. It is a volt-free switch.t
Care must also be taken to avoid induced
voltages caused by the running of the
thermostat cables along side other main voltage
cables.
If using a room thermostat with heat accelerator,
this must be set at 0·12A. The maximum
permissible resistance of the room thermostat
circuit is 22 Ohms. Where a clock thermostat is
employed, the closed-circuit current must not
exceed 20mA when there is no demand for heat.
It is recommended that the room thermostat is not
set lower than 15ºC during the winter months.
Where a 'wireless' room thermostat is employed,
consult the manufacturer’s instructions for
installation.
Warning! The internal electrical
wiring of the Atmos Multi is
complete and must not be changed or
adapted in any way.
The appliance is suitable for connecting an
OpenTherm modulating thermostat instead of an
on/off thermostat. The modulating thermostat
calculates the CH flow temperature at a required
room temperature in order to make optimum use of
the modulating function (ie minimum energy). The
manual supplied with the OpenTherm thermostat
should be consulted for more information.
A wiring diagram of the Atmos Multi is given in
Fig 24.
ATMOS MULTI Mk 2 version 2008
Page 31