11
SAFETY DEVICES
Flue safety device
If an obstruction, even
partial, of the flue oc-
curs, for any reason
whatsoever, the built in
flue safety device will
turn the boiler OFFand
the warning LED on the
Sec 055
In case of loss of water in
the system
CAUTION. The boiler is in-
stalled as part of a sealed
system which must only be
drained and filled by a
competent person.
If the pressure shown on
the pressure gauge,
see
diagram 16
, is less than 1 bar, the system must be
filled up immediately. Call your Installer/Service
Provider.
Overheat safety
In the event of a problem, the overheat safety
device cause safety shutdown of the boiler. If this
happens, call your Installer/Service Provider.
Frost protection
The
THEMA C 23
boiler
has a built in frost pro-
tection device that pro-
tects the boiler from
freezing. If the boiler is to
be left and there is a risk
of frost, ensure that the
gas and electrical sup-
Diagram 17
plies are left connected and that the Summer/Win-
ter switch is in the 'Summer' position.
The frost protection device will light the boiler when
the temperature of the boiler water falls below 6
°
C.
When the temperature reaches 16
°
C, the boiler
stops.
Note:
This device works irrespective of any room
thermostat setting and only protects the boiler.
Important notice
: Under no circumstances must the
flue safety device be bypassed or removed. Any
repairs on the flue safety device must be carried
out by a qualified engineer using genuine replace-
ment parts only.
Air in the heating system
Persistent air in the heating system may indicate
leaks in the system or corrosion taking place. Call
your Installer/Service Provider.
Gas leak or fault
If a gas leak or fault exists or is suspected, turn the
boiler off and consult the local gas undertaking or
your Installer/Service Provider.
In case of power supply failure
The boiler no longer operates.
As soon as power supply is restored, the boiler will
be automatically restarted.
Important notice:
A central heating system cannot
operate satisfactorily unless it is properly filled with
water and unless the air initially contained in the
piping systems has been properly bled off. If these
conditions are not satisfied, air noise will occur
within the system.
Sec 056
SETTINGS
Bypass
The built-in bypass must be adjusted according to
the requirements of the system. Refer to the flow
rate/pressure curve (
diagram 3
). The boiler is sup-
plied with the bypass open half a turn. It is adjusted
by turning the bypass screw,
see diagram 18
. Turn
the screw clockwise to close the bypass.
When using thermostatic radiator valves (TRV's), it
is advisable to fit a separate, adjustable bypass of
15 mm minimum diameter between the flow and
return connections of the heating circuit. Any by-
pass must be fitted before system controls.
Pump operation in heating mode
The PCB can be set to operate the pump in two
ways,
see diagram 19.
Position D: Intermittent pump operation.
With the jumper set to position 'D', the pump will
operate during operation of the room thermostat.
Position C: Continuous pump operation.
With the jumper set to position 'C', the pump will
operate continuously.
Reg 013
Reg 004
Diagram 15
boiler control panel will light. If this occurs, contact
your Installer/Service Provider.
Diagram 16
Diagram 18
Diagram 19
