Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 - Page 56

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Fig. 45 — Typical Component Arrangement — 48PG28
THERMOSTAT/IGC MARKINGS
BM — Blower Motor C—Common CM — Inducer Motor CS — Centrifugal Switch G—Fan IFO — Indoor Fan On L1 — Line 1 R—Thermostat Power RT — Power Supply SS — Speed Sensor W—Thermostat Heat W1 — 1st Stage of Heating W2 — 2nd Stage of Heating X—Alarm Output Y1 — 1st Stage of Cooling Y2 — 2nd Stage of Cooling
LEGEND FOR FIG. 42-45
---A — Circuit A AUX — Auxiliary Contact AL — Ambient Limit ---B — Circuit B C—Compressor Contactor CAP — Capacitor CB — Compressor Circuit Breaker CCH — Crankcase Heater CLO — Compressor Lockout COMP — Compressor CT BRK — Circuit Breaker CR — Control Relay DU — Dummy Terminal ECB — Economizer Control Board FCS — Fan Cycling Switch FIOP — Factory-Installed Option FPT — Freeze Protection Thermostat FS — Flame Sensor FU — Fuse GND — Ground GV — Gas Valve HACR — Heating, Air Conditioning,
and Refrigeration
HERM — Hermetic HPS — High-Pressure Switch I—Ignitor IAQ — Indoor Air Quality IDM — Induced-Draft Motor IDR — Induced Draft Relay IFC — Indoor-Fan Contactor IFCB — Indoor Fan Circuit Breaker IFM — Indoor-Fan Motor IGC — Integrated Gas Controller LOR — Lockout Relay
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 min 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. 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.
LPS — Low-Pressure Switch LS — Limit Switch OAS — Outdoor-Air Sensor OFC — Outdoor-Fan Contactor OFM — Outdoor-Fan Motor PEC — Power Exhaust Contactor PEM — Power Exhaust Motor PL — Plug PLP — Phase Loss Protection QC — Quick Connect QT — Quadruple Terminal RAS — Return Air Sensor RS — Rollout Switch SAT — Supply-Air Temperature TB — Te r m i n al B l o ck TRAN — Transformer TXV — Thermostatic Expansion Valve W/AT — With Auxiliary Trip
Te r m i n al B l o ck Terminal (Unmarked) Te r m i n al ( Marked) Factory Wiring Field Wiring To Indicate Common Potential Only. Not to Represent Wiring. To Indicate FIOP or Accessory