Carrier 48/50AJ specifications Service, 128

SERVICE

WARNING

Before performing service or maintenance operations on unit, turn off main power switch to unit. Electrical shock could cause personal injury.

Service Access — All unit components can be reached through clearly labelled hinged access doors. These doors are not equipped with tiebacks, so if heavy duty servicing is need- ed, either remove them or prop them open to prevent accidental closure.

Each door is held closed with 3 latches. The latches are se- cured to the unit with a single 1/4-in. - 20 x 1/2-in. long bolt. See Fig. 36.

To open, loosen the latch bolt using a 7/16-in. wrench. Pivot the latch so it is not in contact with the door. Open the door. To shut, reverse the above procedure.

NOTE: Disassembly of the top cover may be required under special service circumstances. It is very important that the ori- entation and position of the top cover be marked on the unit prior to disassembly. This will allow proper replacement of the top cover onto the unit and prevent rainwater from leaking into the unit.

IMPORTANT: After servicing is completed, make sure door is closed and relatched properly, and that the latches are tight. Failure to do so can result in water leakage into the evaporator section of the unit.

Cleaning — Inspect unit interior at beginning of each heat- ing and cooling season and as operating conditions require. Remove unit side panels and/or open doors for access to unit interior.

MAIN BURNERS — At the beginning of each heating sea- son, inspect for deterioration or blockage due to corrosion or other causes. Observe the main burner flames and adjust if nec- essary. Check spark gap. See Fig. 37. Refer to Main Burners section on page 139.

FLUE GAS PASSAGEWAYS — The flue collector box and heat exchanger cells may be inspected by removing gas section access panel, flue box cover, collector box, and main burner as- sembly (Fig. 38 and 39). Refer to Main Burners section on page 139 for burner removal sequence. If cleaning is required, clean all parts with a wire brush. Reassemble using new high- temperature insulation for sealing.

A48-3821

Fig. 36 — Door Latch

A48-4022

Fig. 37 — Spark Gap Adjustment

NOTES:

1.Torque set screws on blower wheel to 70 in. lb ± 2 in. lb.

2.Torque set screw on propeller fan to 15 in. lb ± 2 in. lb.

3.Dimensions are in inches.

A48-3822

Fig. 38 — Typical Gas Heating Section

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