Carrier 58MSA → ÐField Wiring, ÐElectrical Controls and Wiring, ÐTroubleshooting

10. Replace main furnace door.

Step 7ÐElectrical Controls and Wiring

There may be more than 1 electrical supply to the unit. Check accessories and cooling unit for additional electrical supplies.

NOTE: Removing blower access panel will open blower access panel door switch and terminate 115-v power to control center, and fault code will be erased. Look into blower access panel sight glass for current LED status.

The unit's component test is a useful troubleshooting tool since it displays the current status (fault code) of the furnace and func- tionally operates all furnace components except the gas valve. The component test and methods to initiate it are described below.

The electrical ground and polarity for 115-v wiring must be maintained properly. Refer to Fig. 11 for field wiring information and to Fig. 15 for unit wiring information.

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

The 24-v circuit contains an automotive-type, 3-amp fuse located on the control center. (See Fig. 12.) Any direct 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 fuse of identical size.

With power to the unit disconnected, check all electrical connec- tions for tightness. Tighten all screws on electrical connections. If any smoky or burned connections are found, disassemble the connection, clean all parts, strip wire, and reassemble properly and securely.

Reconnect electrical supply to unit and observe unit through 1 complete operating cycle. Electrical controls are difficult to check without proper instrumentation; if there are any discrepancies in the operating cycle, contact your dealer and request service.

Step 8ÐTroubleshooting

For an explanation of fault codes, refer to service label located on back of main furnace door or Fig. 16, and the Troubleshooting Guide.

The control center stores 1 fault code (the last fault to occur) for a period of 48 hrs or until the 115- or 24-v power is interrupted.

COMPONENT TEST SEQUENCE

NOTE: All components are functionally operated except the gas valve.

When component test is initiated, the following sequence of events occurs:

1.LED flashes a fault code 4 times.

2.Inducer motor starts and continues to run for remainder of component test.

3.Hot surface ignitor is energized for 15 sec, then de-energized.

4.Main blower operates at cooling speed for 10 sec, then turns off.

5.Main blower operates at heating speed for 10 sec, then turns off.

6.Inducer motor stops.

Component test can be initiated by one of the following proce- dures.

→INITIATING COMPONENT TEST AND RETRIEVING STA- TUS CODE BY REMOVING MAIN LIMIT SWITCH WIRE NOTE: NO thermostat signal may be present at control center and all blower time delay off periods must be completed.

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

2.Remove main furnace door.

3.Look into blower access panel sight glass for current LED status.

NOTE: Leave blower access panel installed to maintain power to control center to view current LED status.

FIELD 24-V WIRING

FIELD 115-, 208/230-, 460-V WIRING

FACTORY 24-V WIRING

FACTORY 115-V WIRING

			NOTE 2				THERMOSTAT
		FIVE		W C R	G	Y		FIELD-SUPPLIED
							TERMINALS
		WIRE						DISCONNECT
		THREE-WIRE						208/230- OR
		HEATING-
		ONLY						460-V
								THREE
BLK	BLK		W					PHASE
WHT	WHT		R
								208/230-V
	GND	GND						SINGLE
	115-V	AUXILIARY	G					PHASE
FIELD-SUPPLIED		J-BOX	C	NOTE 1				GND
DISCONNECT		CONTROL	Y				CONDENSING
		BOX					UNIT
			24-V				TWO
		TERMINAL					WIRE
			BLOCK	NOTES: 1.		Connect Y-terminal as shown for proper operation.
		FURNACE
					2.￿ Some thermostats require a "C" terminal connection as shown.

3.If any of the original wire, as supplied, must be replaced, use same type or equivalent wire.

A98209

→Fig. 11ÐField Wiring

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