Service and Maintenance Procedures | Carrier 58CTA/CTX manual

SERVICE AND MAINTENANCE

PROCEDURES

!WARNING

FIRE, PERSONAL INJURY AND UNIT DAMAGE HAZARD

Failure to follow this warning could result in personal injury, death and/or property damage.

The ability to properly perform maintenance on this equipment requires certain knowledge, mechanical skills, tools, and equipment. If you do not possess these, do not attempt to perform any maintenance on this equipment other than those procedures recommended in the User’s Manual.

!WARNING

ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD

Failure to follow this warning could result in personal injury or death, or property damage.

Before servicing, disconnect all electrical power to furnace. Verify proper operation after servicing.

!CAUTION

UNIT OPERATION HAZARD

Failure to follow this caution may result in improper unit operation or failure of unit components.

Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation.

!CAUTION

ENVIRONMENTAL HAZARD

Failure to follow this caution may result in environmental pollution.

Remove and recycle all components or materials (i.e. oil, refrigerant, control board, etc.) before unit final disposal.

Step 1 — Introduction

GENERAL

These instructions are written as if the furnace is installed in an upflow application. An upflow furnace application is where the blower is located below the combustion and controls section of the furnace, and conditioned air is discharged upward. Since this furnace can be installed in any of the 4 positions shown in Fig. 4, you must revise your orientation to component location accordingly.

ELECTRICAL CONTROLS AND WIRING

!WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

There may be more than one electrical supply to the furnace. Check accessories and cooling unit for additional electrical supplies that must be shut off during furnace servicing.

The electrical ground and polarity for 115-v wiring must be properly maintained. Refer to Fig. 23 for field wiring information and to Fig. 57 for furnace wiring information.

NOTE: If the polarity is not correct, the STATUS LED on the control will flash rapidly and prevent the furnace from heating. The control system also requires an earth ground for proper operation of the control and flame-sensing electrode.

The 24-v circuit contains an automotive-type, 3-amp. fuse located on the control. (See Fig. 31.) Any shorts of the 24-v wiring during installation, service, or maintenance will cause this fuse to blow. If fuse replacement is required, use ONLY a 3-amp. fuse. The control LED will display status code 24 when fuse needs to be replaced.

Proper instrumentation is required to service electrical controls. The control in this furnace is equipped with a Status Code LED (Light-Emitting Diode) to aid in installation, servicing, and troubleshooting. It can be viewed through the sight glass in blower access door. The furnace control LED is either ON continuously, rapid flashing, or a code composed of 2 digits. The first digit is the number of short flashes, the second digit is the number of long flashes.

For an explanation of status codes, refer to service label located on blower access door or Fig. 56, and the troubleshooting guide which can be obtained from your distributor.

See Fig. 61 for a brief Troubleshooting guide.

For Controls with an Amber LED

The stored status codes will NOT be erased from the control memory, if 115- or 24-v power is interrupted. The control will store up to five (5) status codes.

1. To retrieve status codes, proceed with the following:

NOTE: NO thermostat signal may be present at control, and all blower-OFF delays must be completed.

a.Leave 115-v power to furnace turned on.

b.Remove outer access door.

c.Look into blower access door sight glass for current LED status. Removing blower access door will open blower access door switch and terminate 115-v power to control so that status code is not displayed.

d.BRIEFLY remove insulated terminal wire from the draft safeguard (DSS) switch until LED goes out, then recon- nect it.

NOTE: If wire to DSS is disconnected longer than 4 sec, main blower starts, and retrieval request is ignored.

2.When above items have been completed, the LED flashes status code 4 times. Record this status code for further troubleshooting. After the LED flashes status code four times, BRIEFLY remove wire again from DSS switch un- til LED goes out, then reconnect it to retrieve previous status code (if available). Repeat as needed for more previ- ous status codes or until Code 11 appears.