21
Concord CXD -
Installation
26 ADDITIONAL FEATURES OF THE CONTROL SYSTEM
27 DESCRIPTION AND OPERATION OF BOILER CONTROLS
ON / STANDBY [1/0] BUTTON
Turns the boiler on and to STANDBY.
WARNING
.
STANDBY does
NOT
electrically isolate the boiler.
When this switch is in the STANDBY position the display will
show :-
On initial start up the boiler will indicate the hardware and
software code, the boiler type and indicate if the boiler is ON or
STANDBY. If the boiler is at STANDBY the rotating information
screens will not be in evidence.
An example of the display is as follows :-
MONDAY
14 : 10 19 / 09 / 95
ON HIGH 50
°
°
°
°
°
C
HOURS RUN 250
TEMP SET 82
°
°
°
°
°
C
PROGRAMMER ON
"ENTER" FOR MENU
To switch the boiler on press the On/Standby
[1/0] button. The display will show :-
This display will be retained for five seconds
before the information screens are displayed.
INFORMATION SCREENS
If the optional outside temperature kit, enabling
weather compensation, has been fitted the
display will indicate the compensated set point
temperature.
INSTALLATION
INST
ALLA
TION
In addition to the operational characteristics described above,
the control system incorporates the following features
accessible to the user or service engineer:
ADJUSTABLE BOILER TEMPERATURE CONTROL
This is factory pre-set at 82
0
C but may be adjusted by the user
between 60
0
C and 85
0
C. Refer to Frame 30.
PROGRAMMER TIMER
A maximum of 3 time periods per day can be programmed in
to the boiler.
Note
.
This a boiler timer only and does not replace a
conventional system programmer serving more than one
heating zone.
OUTSIDE SENSOR (Optional extra)
If the optional outside sensor is fitted, the control system will
recognise this and automatically regulate the boiler flow
temperature with respect to changes in the external
temperature. If the sensor is fitted, an extra status information
screen will appear stating whether the device has been
activated or not (i.e. compensator on/off).
COMMISSIONING INSTRUCTIONS
These are provided to assist the installer to commission the
boiler.
SERVICING INSTRUCTIONS
These are provided to assist the service engineer.
FAULT DIAGNOSIS
In the unlikely event of a fault condition, the microprocessors
will identify the fault area and display a suitable message on
the display.
Further to these accessible features there are other features
present in the system which the installer/service engineer
should be aware of.
HOURS RUN LOG
This feature enables the installer to determine the workload of
the boiler.
PUMP OVERRUN
If the flow temperature is above 75
o
C at the time of boiler
shutdown, the controls will maintain pump operation until the
residual heat within the appliance has been dispersed and the
flow temp is below 75
o
C.
ANTI-CYCLE DEVICE
On any heating system, if the heating load is very low, there is
a tendency for the boiler to cycle on and off rapidly. This is
inefficient and can lead to shortened boiler life. The high/low
operating system of the
CXD
minimises the risk of this but, in
addition, the controls prevent the boiler from short cycling by
preventing subsequent ignition within a period of 2 minutes.
When active, the display will show:
Summary of Contents for Concord CXD 40-100
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