White Rodgers 50A55-474 user manual

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50A55-474 & 50A55-571
Integrated Furnace Controls
WHITE-RODGERS
INSTALLATION INSTRUCTIONS
Operator: Save these instructions for future use!
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE
INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL
INJURY AND/OR PROPERTY DAMAGE.
DESCRIPTION
The 50A55-474 and 50A55-571 are automatic gas inter-
rupted ignition controls that employ a microprocessor to
continually monitor, analyze, and control the proper op-
eration of the gas burner, indu

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SPECIFICATIONS ELECTRICAL RATINGS [@ 77°F (25°C)]: TIMING SPECIFICATIONS Input Voltage: 25 VAC 50/60 Hz (All times are in seconds, unless noted otherwise) Max. Input Current @ 25 VAC: 0.45 amp 50A55-474 50A55-571 Relay Load Ratings: Valve Relay: 1.5 amp @ 25 VAC 50/60 Hz 0.6 pf PRE-PURGE 0 0 Ignitor Relay: 6.0 amp @ 120 VAC 50/60 Hz (resistive) TRIAL FOR IGNITION 4 4 PERIOD Flame Current Requirements: Minimum current to insure flame detection: 1 μa DC* IGNITION ACTIVATION 1 1 Maximum curr

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INSTALLATION MOUNTING AND WIRING NOTE All wiring should be installed according to local and WARNING ! national electrical codes and ordinances. Do not use on circuits exceeding specified volt- The control must be secured to an area that will experi- age. Higher voltage will damage control and ence a minimum of vibration and remain below the maxi- could cause shock or fire hazard. mum ambient temperature rating of 175°F. The control is approved for minimum ambient temperatures of -40°F. Any orie

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TYPICAL SYSTEM WIRING DIAGRAM HOT NEUTRAL (LINE) (LINE) 120 VAC 24 VAC CLASS II TRANSFORMER TH 24 VAC TR 50A55 COOL HEAT CIRCU- PARK LATOR BLOWER PARK LINE XFMR EAC HUM IND INDUCER IGN IGNITOR IND N HUMIDIFIER IGN N (-474 only) CIR N LINE N XFMR N HUM N ELECTRONIC AIR CLEANER EAC N (-474 only) Y Y COMPRESSOR W W CONTACTOR G G R R THERMOSTAT C PRESSURE SWITCH (N. O.) PS HLI FLAME HLO HIGH LIMIT AUX. HIGH SENSOR FP (N. C.) LIMIT (N. C.) PROBE GND GAS VALVE MV MV TR TH LEGEND Low Voltage (24 VAC) L

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TYPICAL SYSTEM WIRING TABLE 50A55 TERMINAL SYSTEM COMPONENT TERMINAL TYPE CONNECTION W low voltage thermostat W terminal (or equivalent) G Terminal low voltage thermostat G terminal (or equivalent) R block with low voltage thermostat R terminal (or equivalent) Y captive low voltage thermostat Y terminal (or equivalent) screws (2nd wire from Y terminal goes to 24 VAC HOT side of compressor contactor coil) C 24 VAC COMMON side of compressor contactor coil MV (2 terminals) gas

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OPERATION Upon a call for heat, if the warm-up time has not been OPTION SWITCHES locked, it will be decreased by one second. This reduction (50A55-474 only) of the ignitor on-time will continue until flame fails to be achieved (resulting in a retry). The option switches on the 50A55-474 control are used to In the event of a retry, the warm-up time will be increased determine the length of the cool delay-to-fan-off and heat by two seconds and locked at that duration. Once the delay-to-fan-off per

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gize and the control will restart the ignition sequence. A DIAGNOSTIC FEATURES recycle will begin and the burner will operate normally if The 50A55 control continuously monitors its own opera- the gas supply returns, or the fault condition is corrected, tion and the operation of the system. The LED light on the before the last ignition attempt. Otherwise, the control will control will flash slowly (one flash per second) if there are go into system lockout. no failures and no call for heat. If th

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