Ideal Boilers Concord CXD 40-100 Installation & Servicing Manual

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Ideal Boilers Concord CXD 40-100 Installation & Servicing Manual Manual pdf 20 page image

20 Concord CXD - Installation24 ADJUSTING THE MANIFOLD PRESSURES1. Press the [ENTER] button on the fascia panel, then presseither the up or down arrow button until the display shows:then press [ENTER]. The microprocessor is now incommissioning mode. Failure to enter the commissioningmode will result in a fault condition being detected whenthe following actions are carried out.2. If desired, it is possible to use the onboard commissioninginstructions using the up/down arrow buttons. However thefollowing paragraphs provide more detailed instructionsand are recommended until the installer is familiar with theCXD.3. It is essential to adjust the LOW setting first.4. Press the [0/1] button to turn the appliance OFF, thendisconnect the power leads from the right hand (HIGH)gas valve.25 OPERATING INSTRUCTIONSThe CXD features direct burner ignition, high/low burneroperation, and a microprocessor control system.Upon a demand for heat, the controls open the low rate gasvalve and provides a rapid spark at the ignition electrode for upto 10 seconds.The burner will light and remain at low rate for approximately 3minutes before proceeding to high rate (when themicroprocessor opens the remaining gas valve).If the boiler fails to light, the gas valve is closed and there willbe a delay of 1 minute before the cycle is repeated. If, after 5attempts the burner has failed to light, the boiler will go tolockout andwill be displayed on the screen.When the boiler flow temperature reaches the thermostat setpoint, the controls will turn the burner to low rate. If the flowtemperature continues to rise the burner will be turned off at 3oC above the set point.If however the temperature falls below the set point whilst onlow fire, the controls will automatically turn the burner back upto maximum rate.This system has the advantages of ensuring that the boileraccurately maintains the set temperature (without the largetemperature swings that can be associated with on/offboilers), prevents rapid or short cycling, and provides moreefficient system operation.CXD 70, 80 90 &100 ONLY 5. Press the [0/1] button again to light the burner. Allow theburner to run at low rate for several minutes, then checkthat the low burner pressure is as shown in Table 1 forthe appropriate boiler size. If necessary, adjust the lowburner pressure adjusting screw (7).6. Press the [0/1] button to turn the boiler off, reconnect thepower leads to the RH valve and press the [0/1] buttonagain to relight the boiler. Adjust the system controls toallow the boiler to fire at high rate for several minutes,then remove the dust cover and adjust the high burnerpressure adjusting screw (8). After setting to theindicated pressure replace the dust cover and allow theboiler to operate for about 5 minutes to stabilise then re-check the burner pressure.Note. If high rate pressure is not achievable as abovecheck that the gas restrictor in the low-rate valve is fitted(see Frames 38 & 41).7. Press the [0/1] button to turn the boiler off, then refit bothpressure test point screws. Check for gas soundness.8. Press [EXIT] to leave the commissioning mode andreturn to the main menu.9. Press [EXIT] again to return to the status displays.INSTALLATIONINSTALLATIONLEGEND1. Fascia panel display.2. Overheat thermostat resetbutton.3. Main gas inlet cock.4. Union.5. Gas control valve low rate.6. Gas control valve high rate.7. Low rate adjusting screw.8. High rate adjusting screw.9. Burner setting pressure testpoint.10. Inlet pressure test point.11. RH (High) gas valve powerconnector.