White Rodgers FG9 Manual
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035-19592-001 Rev. C (0204)6 Unitary Products GroupIf the flame is not detected within 2 seconds of the gas valve opening,the gas valve is shut off and a retry operation begins. If the flame is lostfor 2 seconds during the 10-second stabilization period, the gas valve isshut off and a retry operation begins. During a retry operation, the ventmotor starts a 15 second inter-purge and the ignitor warm-up time isextended to 27 seconds. If the flame is established for more than 10seconds after ignition during a retry, the control will clear the ignitionattempt (retry) counter. If three retries occur during a call for heat, thefurnace will shut down for one hour. If at the end of the one hour shutdown there is a call for heat, the furnace will initiate a normal start cycle.If the problem has not been corrected the furnace will again lockoutafter three retries.A momentary loss of gas supply, flame blowout, or a faulty flame probecircuit will result in a disruption in the flame and be sensed within 1.0seconds. The gas valve will de-energize and the control will begin arecycle operation. A normal ignition sequence will begin after a 15 sec-ond inter-purge. If during the five recycles the gas supply does notreturn, or the fault condition is not corrected the ignition control will lock-out for 60 minutes.During burner operation, a momentary loss of power for 50 millisecondsor longer will de-energize the gas valve. When the power is restored,the gas valve will remain de-energized and the ignition sequence willimmediately restart.Hot Surface Ignition SystemFURNACE CLEANING SECTIONNOTE: The cleaning operations listed below must be performed only bya qualified service agency.Burner Removal/CleaningThe main burners should be checked periodically for dirt accumulation.If cleaning is required, follow this procedure:1. Turn off the electrical power to the unit.2. Turn off the gas supply at the external manual shut-off valve andloosen the ground union joint.3. Remove the upper access panel and remove the burner box cover.4. Disconnect wires from flame sensor, rollout switch and HSI igniter.Remove igniter carefully, as it is easily broken.5. Remove the screws that hold the burner box assembly to the vestpanel and remove the assembly.6. Remove burners from the burner assembly.7. Burners may be cleaned by rinsing in hot water.8. Reassemble the burners in the reverse order.Cleaning the Heat Exchanger1. Turn off the electrical power to the unit.2. Turn off the gas supply at the external manual shut-off valve andloosen the ground union joint.3. Remove the upper access panel and remove the burner box cover.4. Disconnect wires from flame sensor, rollout switch and HSI igniter.Remove igniter carefully, as it is easily broken.5. Remove the screws that hold the burner box assembly to the vestpanel and remove the assembly.6. Remove burners from the burner assembly.7. Remove the upper cover plate at the top of the furnace. Removethe internal baffle.8. The upper portion of the heat exchanger is now exposed.9. With a long flexible wire brush, clean inside each tube at both thetop and bottom. The brush must pass around the rear heatexchanger tubes and then vacuum loose the scale and dirt fromeach tube.10. Clean - vacuum all burners.11. Replace all components in reverse order. Reconnect all wiring.12. Restore electrical power and gas supply to the furnace.13. Check furnace operation.Cleaning the Secondary Heat Exchanger1. Follow steps 1 - 8 under cleaning the Heat Exchanger.2. Remove the vent piping from the vent blower housing. Disconnectthe drain lines from the vent blower housing and from the conden-sate drain pan. Remove the vent blower housing blower and thecondensate pan. The turbulators can then be gently removed fromthe secondary heat exchanger.3. Using a stiff wire brush, remove the loose scale or soot from eachtube.4. Vacuum the secondary heat exchanger.5. Finish the cleaning procedure by following steps 11 thru 13 undercleaning the Heat Exchanger.TROUBLESHOOTINGThe following visual checks should be made before troubleshooting:1. Check to see that the power to the furnace and the ignition controlmodule is ON.2. The manual shut-off valves in the gas line to the furnace must beopen.3. Make sure all wiring connections are secure.4. Review the sequence of operation. Start the system by setting thethermostat above the room temperature. Observe the system’sresponse. Then use the troubleshooting section in this manual tocheck the system’s operation.FURNACE CONTROL DIAGNOSTICSThe furnace has built-in, self-diagnostic capability. If a system problemoccurs, a blinking red LED shows a fault code. It is located behind aclear view port in the blower compartment door. DO NOT remove thefurnace blower compartment panel OR turn off furnace power, as eitheraction will clear the control’s memory of the fault.The control continuously monitors its own operation and the operationof the system. If a failure occurs, the LED will indicate the failure code. Ifthe failure is internal to the control, the light will stay on continuously. Inthis case, the entire control should be replaced, as the control is notfield repairable.Flash sequence codes 1 through 11 are as follows: LED will turn “on” forone second and “off” for one second. This pattern will be repeated thenumber of times equal to the code. For example, six “on” flashes equalsa number 6 fault code. All flash code sequences are broken by a 2 sec-ond “off” period.HOT SURFACE IGNITION SYSTEMDo not attempt to light this furnace by hand (with amatch or any other means). There may be a potentialshock hazard from the components of the hot surfaceignition system. The furnace can only be lit automaticallyby its hot surface ignition system.Label all wires prior to disconnection when servicingcontrols. Wiring errors can cause improper and danger-ous operation. Verify proper operation after servicing. |
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