Emerson 50A55-843 Installation Instructions
50A55-843
Universal Integrated Furnace Control
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 50A55-843 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.
TRANE APPLICATION - Installer MUST read page 3 “Mounting and Wiring”
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.
Following installation or replacement, follow manufacturer’s
recommended installation/service instructions to ensure proper
operation.
CAUTION
Do not short out terminals on gas valve or primary
control. Short or incorrect wiring may damage the
thermostat.
CONTENTS
Description ...................................................................... 1
Precautions ...................................................................... 1
Specifications .................................................................. 2
Installation ....................................................................... 3
Mounting & Wiring
Operation ......................................................................... 6
Mounting Hole Template .................................................. 8
These controls incorporate system fault analysis for quick gas
flow shut-off, coupled with automatic ignition retry upon sensing
a fault correction.
WARNING
Failure to comply with the following warnings could
result in personal injury or property damage.
FIRE HAZARD
• Do not exceed the specified voltage.
• Protect the control from direct contact with water
(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.
emerson.com/white-rodgers
PART NO. 37-6265001
Replaces 37-6265G
2053
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
*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.
TIMING SPECIFICATIONS
(All times are in seconds, unless noted otherwise)
50A55-843
PRE-PURGE 30
INITIAL IGNITOR WARM-UP
(1st 64 attempts)
MINIMUM IGNITOR WARM-UP 5
MAXIMUM IGNITOR WARM-UP 21
IGNITION ACTIVATION PERIOD 1
TRIAL FOR IGNITION PERIOD 4
RETRIES 2 times
VALVE SEQUENCE PERIOD 12
INTERPURGE 60
POST-PURGE 15
LOCKOUT TIME 300
HEAT DELAY-TO-FAN-ON* 30, 45
HEAT DELAY-TO-FAN-OFF* 60/90/120/180
COOL DELAY-TO-FAN-ON 5
COOL DELAY-TO-FAN-OFF* 45, 90
17
AUTO RESET 60 minutes
HUMIDIFIER YES
ELECTRONIC AIR CLEANER YES
*These times will vary depending on option switch
position. The control is factory-set at 30 seconds heat
delay-to-fan-on, 180 seconds heat delay-to-fan-off and
45 seconds cool delay-to-fan-off. See OPERATION
section for further information.
2
INSTALLATION
MOUNTING AND WIRING
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.).
• 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.
CAUTION
Do not short out terminals on gas valve or primary
control. Short or incorrect wiring may damage the
thermostat.
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.
When mounting the control, any orientation is acceptable.
Choose a location that will not damage, obstruct or place
stress on the control’s terminations, system wiring harness or
system components. After finding a suitable location, drill four
(4) 1/8" holes for mounting control. To ensure proper mounting
hole locations, there is a mounting hole template on page
8 of this instruction sheet. Detach the page with the template
from the instruction sheet and apply it to the mounting location.
When drilling the holes, take care so that the transformer, wiring
harness or other system components are not damaged. Four (4)
#8 sheet metal screws are provided to complete the installation.
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.
Additional jumper wires are included in this package and
should be used if the original wiring does not reach the control
after mounting. Refer to the furnace wiring diagram for proper
connection of the wires.
Amana/Goodman application - An additional wiring harness
(WR 115-0223) is included in this package. If the control being
replaced has a 2-pin (inducer/ignitor) connector, this wiring
harness will adapt the furnace wiring to the 4-pin connector of
the replacement control.
Trane application - Jumper wire 151-2906 (provided with
control) must be installed on the furnace from R01 to R02 of
the 12-pin connector.
3
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