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22 CHECKING THE MANIFOLD PRESSURES
Turn the boiler OFF by pressing the [0/1] button and allow the
flow temperature to cool to less than 50°C.
Connect a pressure gauge to the burner manifold test point
(Frame 23 or 24). Press the [0/1] button again to turn the boiler
ON.
The boiler will operate at low rate for approximately 3 minutes
before proceeding to high rate (this will only happen if the flow
0
temperature is below 55
C otherwise the boiler will proceed
immediately to high rate).
23 ADJUSTING THE MANIFOLD PRESSURES
CXC 48 & 70 ONLY
1. Press the [ENTER] button on the fascia panel, then press
either the [UP] or [DOWN] arrow button until the display
shows:
then press [ENTER]. The microprocessor is now in
commissioning mode. Failure to enter the Commissioning
mode will result in a fault condition being detected when
the following actions are carried out.
2. If desired, it is possible to use the onboard commissioning
instructions, using the [UP] / [DOWN] arrow buttons.
However the following paragraphs provide more detailed
instructions and are recommended until the installer is
familiar with the Concord CXC.
3. It is essential to adjust the maximum setting first.
4. Adjust the system controls to ensure that the boiler will
operate at high rate for a reasonable period, then remove
the dust cover and adjust the high rate burner pressure
setting, using a suitable spanner. Turn the maximum
adjuster (7) clockwise to increase, or anticlockwise to
decrease, the pressure. After setting to the indicated
pressure allow the boiler to operate for about 5 minutes to
stabilise then recheck the burner pressure.
Concord CXC -
Installation
INSTALLATION
Observe the burner pressures and compare them to the
values given in Table 1. If either pressure differs by more than
10%, reset the pressures by following the procedure in Frame
23 or 24.
5. Press the [0/1] button to turn the appliance off, then
disconnect the high/low solenoid connector plug (10)
from the gas valve. Turn the appliance on and repeat the
above sequence but using the low rate adjustment screw
(6) inside the spindle.
6. Turn the appliance off, reconnect the high/low solenoid
plug, refit the dust cover over the adjustment screws and
refit both pressure test point screws. Check for gas
soundness.
7. Press [EXIT] to leave the commissioning mode and
return to the main menu.
8. Press [EXIT] again to return to the status displays.
LEGEND
1. Fascia panel display.
2. Overheat thermostat
reset button.
3. Main gas inlet cock.
4. Union.
5. Gas control valve.
6. Screw - minimum adjuster.
7. Gas rate adjuster - maximum.
8. Burner setting pressure test
point.
9. Inlet pressure test point.
10. High/low solenoid connector.
19
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