Bryant 581A operation manual LEGEND - Low Voltage Control Schematic

LEGEND

Fig. 40 — Low Voltage Control Schematic

Fig. 41 — Power Schematic and Fig. 42 — Component Arrangement

_ _ .A	—	Circuit A	LPS	— Low Pressure Switch
AHA	—	Adjustable Heat Anticipator	LS	— Limit Switch
AL	—	Ambient Limit	MGV	— Main Gas Valve
AUX	—	Auxiliary Contact	OA	— Outdoor Air
_ _ .B	—	Circuit B	OAS	— Outdoor Air Sensor
_ _ .C	—	Circuit C	OAT	— Outdoor-Air Temperature
C	—	Compressor, Contactor	OFC	— Outdoor-Fan Contactor
CAP	—	Capacitor	OFM	— Outdoor-Fan Motor
CB	—	Circuit Breaker	ORH	— Outdoor Relative Humidity
CC	—	Compressor Contactor	PEC	— Power Exhaust Contactor
CCH	—	Crankcase Heater	PEM	— Power Exhaust Motor
CLO	—	Compressor Lockout	PL	— Plug
COMP —		Compressor	QC	— Quadruple Contactor
CR	—	Compressor Relay	QT	— Quadruple Terminal
CS	—	Current Sensor	RAS	— Return Air Sensor
DU	—	Dummy Terminal	RAT	— Return Air Thermostat
FCS	—	Fan Cycling Switch	RS	— Rollout Switch
FIOP	—	Factory-Installed Option	SAT	— Supply-Air Temperature
FPT	—	Female Pipe Thread	TB	— Terminal Block
FS	—	Flame Sensor	TC	— Thermostat Cooling
FU	—	Fuse	TH	— Thermostat Heating
GND	—	Ground	TRAN	— Transformer
GV	—	Gas Valve		Terminal (Marked)
GVR	—	Gas Valve Relay		Terminal (Unmarked)
HACR	—	Heating, Air Conditioning, and Refrigeration
HS	—	Heat Sensor		Terminal Block
HERM —		Hermetic		Splice
HPS	—	High-Pressure Switch
				Splice (Marked)
I	—	Ignitor
IA	—	Indoor Air		Splice (Field Supplied)
IAQ	—	Indoor-Air Quality		Factory Wiring
IDM	—	Induced-Draft Motor
				Field Control Wiring
IFC	—	Indoor-Fan Contactor
IFCB	—	Indoor-Fan Circuit Breaker		Field Power Wiring
IFM	—	Indoor-Fan Motor		Accessory or Optional Wiring
IGC	—	Integrated Gas Controller
IRH	—	Indoor Relative Humidity		To Indicate Common Potential Only,
LAFC	—	Low Ambient Fan Control		Not To Represent Wiring

		THERMOSTAT/IGC MARKINGS
BM —		Blower Motor	RS	—	Rollout Switch
C	—	Common	RT	—	Power Supply
CM —		Inducer Motor	SS	—	Speed Sensor
CS	—	Centrifugal Switch	W	—	Thermostat Heat
G	—	Fan	W1	— 1st Stage of Heating
GV	—	Gas Valve	W2	— 2nd Stage of Heating
IFO —		Indoor Fan On	X	—	Alarm Output
LI	—	Line I	Y1	— 1st Stage of Cooling
R	—	Thermostat Power	Y2	—	2nd Stage of Cooling

NOTES:

1.Factory wiring is in accordance with the National Electrical Codes. Any field modifications or additions must be in compliance with all applicable codes.

2.Use 75 C minimum wire for field power supply. Use copper wires for all units.

3.All circuit breakers “Must Trip Amps” are equal to or less than 156% RLA (rated load amps).

4.Compressor and fan motors are thermally protected. Three-phase motors protected against primary single phase conditions.

5.The CLO locks out the compressor to prevent short cycling on compressor overload and safety devices; before replacing CLO, check these devices.

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