White Rodgers 50A55-474, 50A55-571 User Manual

50A55-474 & 50A55-571

WHITE-RODGERS

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.

The 50A55-474 and 50A55-571 are automatic gas inter­rupted ignition controls that employ 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.

Integrated Furnace Controls

INST ALLA TION INSTRUCTIONS

DESCRIPTION

GENERAL PRECAUTION

!

Application of this type of control may cause
flame rollout on initial start-up and could cause
personal injury and/or property damage.

Replace only with exact model number, includ­ing dash number. Failure to use exact replace­ment control could cause personal injury and/or
property damage.

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.

CONTENTS

Description......................................................... 1

Precautions........................................................ 1

Specifications..................................................... 2

Installation.......................................................... 3

Mounting & Wiring

Operation ........................................................... 6

PRECAUTIONS

CAUTION

!

To prevent electrical shock and/or equipment
damage, disconnect electric power to system at
main fuse or circuit breaker box until installation
is complete.

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

This control is not intended for use in locations
where it may come in contact with water. Suit­able protection must be provided to shield the
control from exposure to water (dripping, spray­ing, rain, etc.).

WARNING

!

Do not use on circuits exceeding specified volt­age. Higher voltage will damage control and
could cause shock or fire hazard.

Do not short out terminals on gas valve or pri­mary control to test. Short or incorrect wiring will
damage thermostat and could cause personal
injury and/or property damage.

WHITE-RODGERS DIVISION

EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398

Printed in U.S.A.

PART NO. 37-5800C

Replaces 37-5800B

9751

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)

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

* Measured with a DC microammeter in the flame probe

lead

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.

(All times are in seconds, unless noted otherwise)

TIMING SPECIFICATIONS

50A55-474

PRE-PURGE
TRIAL FOR IGNITION

PERIOD
IGNITION ACTIVATION

PERIOD
RETRIES
VALVE SEQUENCE

PERIOD
INTERPURGE
POST-PURGE
LOCKOUT TIME
DELAY TO HEAT ON

DELAY TO HEAT OFF

DELAY TO COOL ON
DELAY TO COOL OFF
MINIMUM IGNITOR

WARM-UP
MAXIMUM IGNITOR

WARM-UP
INITIAL IGNITOR

WARM-UP (1st 64
attempts)

HUMIDIFIER
ELECTRONIC AIR

CLEANER

* These times will vary depending on option switch

position. The control is factory-set at 0 sec. delay
to cool off and 100 sec. delay to heat off. See
OPERATION section for further information.

†

This time will vary depending on the condition of

the jumper. With the jumper installed, the delay-to­cool-off is set at 0 seconds. To obtain an 80­second delay-to-cool-off, clip the jumper wire and
separate the jumper legs.

0

4

1

2 times

12

60

5

300

45

60/100/

140/180*

2

0/80*

11

21

17

YES

YES

50A55-571

0

4

1

2 times

12

60

5

300

45

100

2

†

0/80

11

21

17

NO

NO

2

INSTALLATION

MOUNTING AND WIRING

WARNING

!

Do not use on circuits exceeding specified volt­age. Higher voltage will damage control and
could cause shock or fire hazard.

CAUTION

!

To prevent electrical shock and/or equipment
damage, disconnect electric power to system at
main fuse or circuit breaker box until installation
is complete. Failure to earth ground the appli­ance or reversing the neutral and hot wire con­nection to the line can cause shock hazard.

Shut off main gas to heating system until instal­lation is complete.

Route and secure all wiring as far from flame
as practical to prevent fire and/or equipment
damage.

NOTE

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 con-

necting 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.

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.

3