York P*DU-”V” User's Information, Maintenance And Service Manual

Contents

York P*DU-”V” User's Information, Maintenance And Service Manual Manual pdf 8 page image

035-19913-001 Rev. A (0404)8 Unitary Products GroupHot 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 burner door 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 ExchangerLower Heat Exchanger Access1. Turn off the electrical power to the unit and turn off gas supply atthe shutoff valve.2. Remove the blower and burner compartment access doors. Dis-connect the gas supply piping at the union to permit removal of theentire burner and gas control assembly from the vestibule panel.Use the wrench boss on the gas valve when removing or installingthis piping. See Figure 4.3. Unplug the igniter from the wire harness. Disconnect sensor androllout switch wires located on top of the air shield. Identify andnote the location of all leads for ease of reinstallation. Also discon-nect the wires at the side rollout switches (upflow only) and the gasvalve wires.4. Remove the screws holding the burner assembly to the vestibulepanel and remove this assembly. Handle the assembly carefullysince it contains the igniter, which is fragile and easily broken. Thelower portion of the heat exchanger will now be exposed. To cleanthe burner assembly, use a vacuum cleaner, or remove the burn-ers as outlined in burner cleaning, and clean in hot water.Upper Heat Exchanger Access1. Perform steps 1-4 above.2. Disconnect vent piping from the vent motor assembly at the toppanel on the furnace (upflow only). On downflow models, the ventpipe is secured to the vent motor outlet with a screw. Remove thisscrew before proceeding.3. Unplug the vent motor wires and ground wire. Remove the pres-sure switch tubing at the top on the vent motor housing.NOTE: It is recommended that replacement gaskets be availablebefore removing vent motor.1. Remove six mounting screws that hold the vent motor to therestrictor plate. The surface is gasketed and the gasket can bereused if it is carefully removed. It is necessary to remove thisassembly to gain access to the restrictor plate mounting holes.The assembly may be vacuumed if cleaning is necessary. If anyvent assembly parts are damaged, replace with an entire newassembly (except for gaskets).2. Remove the perimeter screws attaching the restrictor plate assem-bly to the vestibule panel. The surface is also gasketed. Theassembly, including the flue baffle plate (rear) may be vacuumedor cleaned with hot water if necessary.3. The upper portion of the heat exchanger is now accessible. With along flexible wire brush, clean inside each tube at both the top andbottom. The brush must pass around the rear heat exchangertubes. Vacuum loose scale and dirt from each tube.4. Clean - Replace all components in reverse order. Re-gasket allsurfaces which required a gasket. Reconnect all wiring. Reattachvent pipe and gas supply lines before restoring service to furnace.Restore electrical power, check gas supply piping for leaks, andthen verify 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.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.