Carrier SINGLE PACKAGE ROOFTOP UNITS ELECTRIC COOLING/GAS HEATING 48HJ015-025 User Manual

Also see for 48EJ: Installation, Start-Up and Service Instructions Installation and service instructions

Contents

SERVICE AND REPLACEMENT (See Fig. 30) — The48HJ017,025 units use a fan motor mounting system thatfeatures a slide-out motor mounting plate. To replace or serv-ice the motor, slide out the bracket.1. Remove the evaporator-fan access panel and the heat-ing control access panel.2. Remove the center post (located between the evaporatorfan and heating control access panels) and all screwssecuring it.3. Loosen nuts on the two carriage bolts in the motor mount-ing base.4. Using jacking bolt under motor base, raise motor to topof slide and remove belt. Secure motor in this positionby tightening the nuts on the carriage bolts.5. Remove the belt drive.6. Remove jacking bolt and tapped jacking bolt plate.7. Remove the 2 screws that secure the motor mountingplate to the motor support channel.8. Remove the 3 screws from the end of the motor supportchannel that interfere with the motor slide path.9. Slide out the motor and motor mounting plate.10. Disconnect wiring connections and remove the 4 mount-ing bolts.11. Remove the motor.12. To install the new motor, reverse Steps 1-11.Belt Tension Adjustment — To adjust belt tension:1. Loosen fan motor bolts.2. a. 015 Units: Move motor mounting plate up or downfor proper belt tension (1 ⁄2 in. deflection with onefinger).b. 017,025 Units: Turn motor jacking bolt to move mo-tor mounting plate up or down for proper belt tension(3⁄8 in. deflection at midspan with one finger [9 lb force]).3. Tighten nuts.4. Adjust bolts and nut on mounting plate to secure motorin fixed position.Condenser-Fan Adjustment48HJ015,017 UNITS (Fig. 31)1. Shut off unit power supply.2. Remove access panel(s) closest to the fan to beadjusted.3. Loosen fan hub setscrews.4. Adjust the fan height on the shaft using a straightedgeplaced across the fan orifice.5. Tighten setscrews and replace panel(s).6. Turn on unit power.48HJ025 UNITS (Fig. 32)1. Shut off unit power supply.2. Remove fan top-grille assembly and loosen fan hub screws.3. Adjust fan height on unit, using a straightedge placed acrossthe fan orifice.4. Tighten setscrews and replace rubber hubcap to preventhub from rusting to motor shaft.5. Fill hub recess with permagum if rubber hubcap ismissing.Economizer Adjustment — Refer to Tables 8 and 9for economizer checkout procedures. Make certain the outdoor-air damper is fully closed and the return-air damper is fullyopen before completing the following steps:1. Turn on power to the unit.2. Turn the thermostat fan switch to the ON position. Thedamper will go to the vent position.3. Adjust the vent position with the minimum position ad-justment on the economizer motor control module. SeeFig. 18.4. Set the system selector switch to COOL position and setthe cooling temperature selector to its lowest setting.NOTE: The Cooling mode may also be simulated byremoving the thermostat wires from terminals Y1 andY2 and installing a jumper between terminals R and Y1.Refer to unit label diagram for terminal locations.NOTE: A 31 ⁄ 2-in. bolt and threaded plate are included in the installer’spacket. They can be added to the motor support channel below themotor mounting plate to aid in raising the motor.Fig. 30 — 48HJ017,025 Evaporator-FanMotor SectionFig. 31 — Condenser Fan Adjustment,48HJ015,017Fig. 32 — Condenser-Fan Adjustment,48HJ02520