Carrier 58MXA Service And Maintenance Instructions

Also see for GAS FURNACE 58MXA: User's information manual User manual Service and maintenance instructions User's information manual User's information manual

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Carrier 58MXA Service And Maintenance Instructions Manual pdf 6 page image

ELECTRICAL SHOCK AND UNIT DAMAGEHAZARDFailure to follow this caution may result in minor personalinjury or furnace component damage.Label all wires prior to disconnection when servicing con-trols. Wiring errors can cause improper and dangerousoperation.3. Disconnect wires or connectors to flame rollout switch, gasvalve, igniter, and flame sensor.4. Disconnect combustion-air intake pipe from intake housing.5. Remove the pressure switch tube from intake housing.6. Remove screws attaching intake housing to burner box, androtate intake housing away from burner box for removal.7. Using backup wrench, disconnect gas supply pipe from gasvalve.8. Disconnect pressure tubing from gas valve.9. Remove 2 screws attaching top filler panel and rotate upwardsto gain access to screws attaching burner box to cell panel.10. Remove screws attaching burner box to cell panel. (See Fig.5.)NOTE: Burner box cover, manifold, gas valve, and burnerassembly should be removed as 1 assembly.11. Clean heat exchanger openings with a vacuum and a softbrush. (See Fig. 6.)NOTE: After cleaning, inspect the heat exchangers to ensure theyare free of all foreign objects that may restrict flow of combustionproducts.12. Reverse items 4 through 10 for reassembly.UNIT MAY NOT OPERATEFailure to attach this ground wire to an adequate casingground may cause the furnace control to lock out.The ground wire from the gas valve MUST be attached to theburner box attachment screw.NOTE: Be sure burner box gasket is installed between burner boxand cell panel. (See Fig. 5.) If gasket is damaged, replace it.NOTE: Inspect combustion-air intake housing. If foamed gasketwas removed, check for any damage. If gasket is damaged in anyway, it must be repaired. To repair, remove damaged gasketsection, apply sealant releasing agent such as PAM cooking sprayor equivalent (must not contain corn or canola oil, aromatic orhalogenated hydrocarbons or inadequate seal may occur) to burnerbox and apply a small bead of G.E. RTV 162, G.E. RTV 6702, orDow-Corning RTV 738 sealant to edge of combustion-air intakehousing. (See Fig. 7.)13. Refer to furnace wiring diagram and reconnect wires to flamerollout switch, gas valve, igniter, and flame sensor.14. Reconnect pressure switch tubes to gas valve and intakehousing. Refer to tube routing label on main furnace door forproper tube location. Be sure tubes are not kinked. (See Fig.8.)15. Turn on gas and electrical supplies to furnace.16. Check furnace operation through 2 complete heat operatingcycles. Look through sight glass in burner enclosure to checkburners. Burner flames should be clear blue, almost transpar-ent. (See Fig. 9.)FIRE OR EXPLOSION HAZARDFailure to follow the safety warnings exactly could result inserious injury, death, or property damage.Never test for gas leaks with an open flame. Use a commer-cially available soap solution made specifically for thedetection of leaks to check all connections. A fire or explo-sion may result causing property damage, personal injury, orloss of life.17. Check for gas leaks.18. Replace main furnace door.SECONDARY HEAT EXCHANGERSNOTE: The condensing side (inside) of the secondary heatexchangers CANNOT be serviced or inspected. A small number ofbottom outlet openings can be inspected by removing the inducerassembly. See Flushing Collector Box and Drainage Systemsection for details on removing inducer assembly.Step 5—Flushing Collector Box and Drainage System1. Turn off gas and electrical supplies to furnace.2. Remove main furnace door.3. Disconnect inducer motor and pressure switch wires orconnectors.4. Disconnect pressure switch tubes.5. Disconnect vent pipe from inducer housing outlet by loosen-ing coupling clamp on inducer outlet.Fig. 6—Cleaning Inlet Openings of Primary HeatExchangersA96305PRIMARY HXINLET OPENINGSFig. 7—Combustion-Air Intake Housing GasketRepairA93087PAMRTV6→→