White Rodgers 50A55-743 User Manual

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50A55-743

Integrated Furnace Control

INSTALLATION INSTRUCTIONS

FAILURETO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL INJURY AND/OR PROPERTY DAMAGE.

DESCRIPTION

The 50A55-743 is an automatic gas interrupted ignition control that employs a microprocessor to continually monitor, analyze, and control the proper operation of the gas burner, inducer, and fan.

Signals interpreted during continual surveillance of the thermostat and flame sensing element initiate automatic ignition of the burner, sensing of the flame, and system shut-off during normal operation.

These controls incorporate system fault analysis for quick gas flow shut-off, coupled with automatic ignition retry upon sensing a fault correction. It is designed as a replacement for the following controls:

 

Goodman

 

White-Rodgers

 

 

 

 

 

 

0130F00005

PCBBF110

PCBBF123

50A55-743

 

0130F00005S

PCBBF110S

PCBBF123S

50A55-289

 

B1809926

PCBBF112

 

50T55-289

 

B1809926S

PCBBF112S

 

 

 

 

 

 

 

 

PRECAUTIONS

Installation should be done by a qualified heating and air conditioning contractor or licensed electrician.

If in doubt about whether your wiring is millivolt, line, or low voltage, have it inspected by a qualified heating and air conditioning contractor or licensed electrician.

Do not exceed the specification ratings.

All wiring must conform to local and national electrical codes and ordinances.

This control is a precision instrument, and should be handled carefully. Rough handling or distorting components could cause the control to malfunction.

Followinginstallationorreplacement,followmanufacturer’s recommended installation/service instructions to ensure proper operation.

! CAUTION

Donotshortoutterminalsongasvalveorprimary control. Short or incorrect wiring may damage the thermostat.

!WARNING

Failure to comply with the following warnings could result in personal injury or property damage.

FIRE HAZARD

Do not exceed the specified voltage.

Replace existing control with exact model and dash number.

Protectthecontrolfromdirectcontactwithwater

(dripping, spraying, rain, etc.).

If the control has been in direct contact with water, replace the control.

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

Route and secure wiring away from flame.

SHOCK HAZARD

Disconnect electric power before servicing.

Ensure proper earth grounding of appliance.

Ensure proper connection of line neutral and line hot wires.

EXPLOSION HAZARD

Shut off main gas to appliance until installation is complete.

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PART NO. 37-7348A

 

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1226

SPECIFICATIONS

ELECTRICAL RATINGS [@ 77°F (25°C)]: Input Voltage: 25 VAC 50/60 Hz

Max. Input Current @ 25 VAC: 0.45 amp Relay Load Ratings:

Valve Relay: 1.5 amp @ 25 VAC 50/60 Hz 0.6 pf Ignitor Relay: 6.0 amp @ 120 VAC 50/60 Hz

(resistive)

Inducer Relay: 2.2 FLA–3.5 LRA @ 120 VAC Circulator Relay: 14.5 FLA–25.0 LRA @ 120 VAC

Flame Current Requirements:

Minimum current to insure flame detection: 1 µa DC* Maximum current for non-detection: 0.1 µa DC* Maximum allowable leakage resistance: 100 M ohms

*MeasuredwithaDCmicroammeterintheflameprobelead

OPERATING TEMPERATURE RANGE:

-40° to 175°F (-40° to 80°C)

HUMIDITY RANGE:

5% to 93% relative humidity (non-condensing)

MOUNTING:

Surface mount multipoise

 

Timing Specs: (@ 60 Hz**)

maximum

 

Flame Establishing Time:

0.8 sec

Flame Failure Response Time:

2.0 sec

**At 50 Hz, all timing specifications should be increased by 20%

Gases Approved: Natural, Manufactured, Mixed, Liquified Petroleum, and LP Gas Air Mixtures are all approved for use.

TIMING SPECIFICATIONS

(All times are in seconds, unless noted otherwise

 

50A55-743

Pre-Purge

15

Initial Ignitor Warm-up

7

(1st 64 attempts)

 

Minimum Ignitor Warm-up

5

Maximum Ignitor Warm-up

9

Ignition Activation Period

2

Trial for Ignition Period

4

Retries

2 times

Valve Sequence Period

12

Interpurge

30

Post-Purge

15

Lockout Time

300

Heat Delay-To-Fan-On

30

Heat Delay-To-Fan-Off*

90/120/150/180

Cool Delay-To-Fan-On

5

Cool Delay-To-Fan-Off

45

Auto Reset

60 minutes

Humidifier

Yes

Electronic Air Cleaner

Yes

*These times will vary depending on option switch position. See OPERATION section for further information

INSTALLATION

MOUNTING AND WIRING

All wiring should be installed according to local and national electrical codes and ordinances.

The control must be secured to an area that will experience a minimum of vibration and remain below the maximum ambient temperature rating of 175°F. The control is approved for minimum ambient temperatures of -40°F.

Any orientation is acceptable.

Refer to the wiring diagram and wiring table when connecting the 50A55 control to other components of the system.

UL approved, 105°C rated 18 gauge, stranded, 2/64” thick insulation wire is recommended for all low voltage safety circuit connections.Refer to 50A55 specification sheet for recommended terminals to mate with those on the control.

UL approved 105°C rated 16 gauge min., stranded, 4/64” thick insulation wire is recommended for all line voltage connections. Refer to 50A55 specification sheet for recommended terminals to mate with those on the control.

After installation or replacement, follow appliance manufacturer’s recommended installation or service instructions to ensure proper operation.

The 50A55 has only one serviceable part–an automotive type fuse, which protects the low voltage transformer from damage if its output is short-circuited. If the fuse has opened up, remove whatever caused the short circuit and replace the fuse with only a 3 Amp automotive type fuse. If the fuse is not the cause of the control’s problem, replace the entire 50A55 control.There are no other user serviceable parts.

! CAUTION

Donotshortoutterminalsongasvalveorprimary control. Short or incorrect wiring may damage the thermostat.

!WARNING

FIRE HAZARD

Do not exceed the specified voltage.

Replace existing control with exact model and dash number.

Protect the control from direct contact with water

(dripping, spraying, rain, etc.).

Ifthecontrolhasbeenindirectcontactwithwater, replace the control.

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

Route and secure wiring away from flame.

SHOCK HAZARD

Disconnect electric power before servicing.

Ensure proper earth grounding of appliance.

Ensure proper connection of line neutral and line hot wires.

EXPLOSION HAZARD

Shut off main gas to appliance until installation is complete.

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White Rodgers 50A55-743 User Manual

WIRING

 

TYPICAL SYSTEM WIRING DIAGRAM

 

HOT

 

NEUTRAL

(LINE)

120 VAC

(LINE)

 

 

24 VAC CLASS II TRANSFORMER

TH

24 VAC

TR

 

 

50A55

 

 

 

COOL

 

 

 

HEAT

 

CIRCULATOR

 

PARK

 

 

 

BLOWER

 

PARK

 

 

 

 

 

LINE

 

 

 

XFMR

 

 

 

EAC

INDUCER

 

 

HUM

 

 

IND-N

 

 

 

IND

 

 

 

IGN

 

 

HUMIDIFIER

IGN-N

IGNITOR

 

 

 

 

 

CIR N

 

 

 

LINE N

 

 

 

XFMR N

 

 

ELECTRONIC

HUM N

 

 

EAC N

 

 

AIR CLEANER

 

 

 

 

 

 

Y

Y

 

 

W

W

COMPRESSOR

 

 

 

CONTACTOR

50A55

G

G

 

 

 

 

in other

R

R

 

furnace(s)

 

 

THERMOSTAT

 

TWINNING

C

 

 

 

APPLICATIONS

 

 

 

ONLY

 

 

 

TWIN*

TWIN*

 

 

 

 

PRESSURE SWITCH (N. O.)

 

PS

 

 

 

PSO

 

 

 

HLI

 

 

FLAME

HLO

HIGH LIMIT

AUX. HIGH

SENSOR

FP

(N. C.)

LIMIT (N. C.)

PROBE

RO1

ROLLOUT

 

 

GND

 

 

RO2

(N. C.)

GAS

 

 

 

MV

 

VALVE

 

MV

 

 

 

TR

 

 

 

TH

 

 

LEGEND

 

 

 

 

Low Voltage (24 VAC)

* The twinning feature is available only on models with

 

 

Line Voltage (120 VAC)

six screw terminals; one of these terminals will be

 

designated “TWIN”. All 50A55 controls used in

N. C. = Normally closed switch

twinning applications must have the “TWIN” terminal.

N. O. = Normally open switch

 

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