White Rodgers 50T35-743 User manual

WARNING
Failure to comply with the following
warnings could result in personal injury
or property damage.
50T35-743
Integrated Furnace Control
FAILURETOREADANDFOLLOWALLINSTRUCTIONSCAREFULLYBEFORE
INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL
INJURY AND/OR PROPERTY DAMAGE.
PART NO. 37-6533B
Replaces 37-6533A
0614
DESCRIPTION
INSTALLATION INSTRUCTIONS
The50T35-743isanautomatic gasinterruptedignition controlthatemploys amicroprocessorto continuallymonitor,analyze, and
controlthe proper operationofthe gas burner,inducer, and fan.Signalsinterpreted during continualsurveillanceof thethermostat
and flame sensing element initiate automatic ignition of the burner, sensing of the flame, and system shut-off during normal
operation. This control incorporates 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:
PRECAUTIONS
FIRE HAZARD
• Do not exceed the specified voltage.
• Protect the control from direct contact with water
(dripping, spraying, rain, etc.).
• Ifthe controlhas been indirect contactwith water,
replace the control.
• Label all wires before disconnection when servic-
ing 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.
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 condi-
tioning 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.Roughhandlingordistortingcomponentscouldcause
the control to malfunction.
Following installation or replacement, follow manufacturer’s
recommendedinstallation/serviceinstructions toensureproper
operation.
CAUTION
Do not short out terminals on gas valve or primary
control. Short or incorrect wiring may damage the
thermostat.
Model Replaces
White-Rodgers 50T35-743 Goodman B18099-06
Goodman B18099-08
Goodman B18099-10
Goodman B18099-13
Index Page
Description 1
Precautions 1
Specifications 2
Installation 3
Typical System Wiring 5
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2
SPECIFICATIONS
ELECTRICAL RATINGS [@ 77°F (25°C)]:
Input Voltage: 25 VAC 60 Hz
Max. Input Current @ 25 VAC:
0.5 amp + Main Value Load
Relay Load Ratings:
Valve Relay: 1.5 amp @ 24 VAC 60 Hz 0.6 pf
Ignitor Relay: 5.0 amp @ 120 VAC 60 Hz
(resistive)
Circulator Relay: 11 FLA–26.0 LRA @ 120 VAC
Humidifier Load Rating: 0.5A @ 24 VAC
1.0A @ 120 VAC
ElectronicAirCleanerLoadRating:1A@120VAC
Flame Current Requirements:
Minimum current to insure flame detection: 1 µa DC*
Maximum current for non-detection: 0.1 µa DC*
Maximumallowableleakageresistance:100Mohms
*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: maximum
Flame Establishing Time: 0.8 sec
Flame Failure Response Time: 2.0 sec
GasesApproved: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)
Timing Specification Description 50T35-743
Pre-Purge Initial delay between thermostat contact closure and trial for ignition. 15
Initial Ignitor Warm-Up Duration of ignitor warm-up time on the first 64 attempts. 15
Retry Ignitor Warm-Up Duration of ignitor warm-up time if the control retries. 20
Ignition Activation Period The period of time between energizing the main gas valve and deactivation of 5
the ignition means prior to the lockout time.
Trial for Ignition Period during which the valve and ignition source is activated, attempting to 7
ignite gas at the burner.
Retries Additional ignition attempts if the original ignition attempt is unsuccessful. 2 times
Valve Sequence Period Valve sequence period is the cumulative total amount of time that the gas valve 12
is energized before entering lockout.
Inter-Purge Period between trials for ignition when both the gas valve and ignition source 30
are deactivated to allow unburned gas to escape before the next trial.
Post-Purge After all ignition cycles are complete, the control will enter post-purge. The 25/29
combustion fan will remain on to allow unburned gas to escape. After post-purge (90+ option)
is complete, the combustion fan will turn off.
Lockout Time The period of time between initiation of gas flow and the action to shut off the gas 300
flow in the event of failure to establish proof of the supervised ignition source or
the supervised main burner flame. Reinitiating the lighting sequence requires a
manual operation if ignition is required before Auto reset.
Heat Delay to Fan On Timing to allow the heat to build up in the plenum before turning on the fan. 30
Heat Delay to Fan Off* Timing to allow the fan to run after the call for heat ends. This allows residual heat 90/120/150
to be removed from the heat exchanger and distributed to the conditioned space.
Cool Delay to Fan On Timing to allow the cooling coils to cool off before turning on the fan. 5
Cool Delay to Fan Off Timing to allow the fan to run after the call for cool ends. This allows residual 60
cooling capacity to be removed from the cooling coils and distributed to the
conditioned space.
Auto Reset If shutoff occurs, the control delays for a specific recycle delay period before 60 minutes
beginning another trial for ignition (models with retries only).
* These times will vary depending on option switch position. See INSTALLATION section for further information.

3
WARNING
CAUTION
FIRE HAZARD
• Do not exceed the specified voltage.
• Protect the control from direct contact with water
(dripping, spraying, rain, etc.).
• Label all wires before disconnection when servic-
ing controls. Wiring errors can cause improper
and dangerous operation.
• Route and secure wiring away from flame.
Do not short out terminals on gas valve or pri-
marycontrol.Shortorincorrectwiringmaydam-
age the thermostat.
MOUNTING AND WIRING
All wiring should be installed according to local and na-
tional electrical codes and ordinances.
The control must be secured to an area that will experi-
ence a minimum of vibration and remain below the maxi-
mumambient temperature rating of 175°F.The controlis
approved for minimum ambient temperatures of -40°F.
Any orientation is acceptable.
Refer to the wiring diagram and wiring table when
connecting the 50T35 control to other components of
the system.
UL approved, 105°C rated 18 gauge, stranded, 2/64”
thickinsulationwireisrecommendedforalllowvoltage
safety circuit connections.
UL approved 105°C rated 16 gauge min., stranded, 4/64”
thick insulation wire is recommended for all line voltage
connections.
Follow the appliance manufacturer’s recommended in-
stallation or service instructions.
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.
INSTALLATION
Remove both access panels.
For GMP & GMPV series units, cut the white jumper wire
between pins 4 & 7 of the 9 pin connector.
For GMPN & GMN series units, DO NOT cut the white
jumper wire.
Removetheedgecardconnectorandotherwiresfromthe
existing module. Discard the thermostat wires re-
moved from the board (R, W & G).
Remove the existing HSI module. Care should be exer-
cised to avoid damage to the nylon standoffs.
Install the 50T35-743 module.
Reconnect the edgecard connector making sure of good
contact.
Pushthe9pin connectorintotheHSImodule. Itcangoin
only one way. DO NOT force.
Reconnect the supplied thermostat wires.
Removetheredwirefromthe24voltsideofthesecondary
side of the transformer and discard.
Remove the blue ground wire from the transformer. DO
NOT discard.
Remove the blue wire from the transformer and discard.
Connectthe red wire from the9 pinconnector to"24 volt"
of the secondary side of the transformer.
Connect the blue wire from the 9 pin connector to "Com-
mon" terminal of the secondary side of the trans-
former. This wire has a piggy back terminal.
Connect the blue ground wire, which was previously
removed,alsotothe"Common"terminalofthetrans-
former.
Replace the access panels.
Restore gas and electrical power to the furnace.
Verify the sequence of operation as noted in the furnace
manufacturers Installation & Operating Instructions.
Black
White
24 v. Red
Com. Blue
GND. Blue
TRANSFORMER
115v. Supply
The 50T35 has only one serviceable part–an automotive
typefuse,whichprotectsthelowvoltagetransformerfrom
damage if its output is short-circuited. If the fuse has
openedup,removewhatevercausedtheshortcircuitand
replace the fuse with the same type 3 Amp automotive
fuse.Ifthecontroldoesnotoperatecorrectlyafterreplac-
ing the fuse, replace the entire 50T35 control. There are
no other user serviceable parts.

4
INSTALLATION
SELECTING THE BLOWER OFF DELAY
Inthe heatingmode,the bloweroffdelay canbeselected
to obtain a 90, 120 or 150 seconds period. This can be
accomplishedbychangingthepositionofaplasticjumper
located on the ignition control. See the drawing below for
the location of this jumper.
Thecontrolisfactorysettogivea(150)secondbloweroff
delay. See drawing below for the jumper position for all
available settings:
Notes:
• If the jumper is removed, the control will default to a
(150) second blower off delay in the heating mode.
• The blower on time in the heating mode is (30)
seconds and is non-adjustable.
• Theblowerontimeinthecoolingmodeis(5)seconds
and is non-adjustable.
• The blower off delay in the cooling mode is (60)
seconds and is non-adjustable.
• Caution is to be exercised not to bend the metal pins
whenchangingthetimedelayfromthefactorysetting.
DIAGNOSTIC FEATURES
The 50T35-743 control continuously monitors its own
operationandtheoperationofthesystem.Ifafaultoccurs,
the LED will indicate a fault code as shown below. If the
fault is internal to the control, the light will stay off. In
thiscase,theentirecontrolshouldbereplaced,asthe
control is not field-repairable.
If the sensed failure is in the system (external to the
control), the LED will flash in the following flash-pause
sequences to indicate failure status (each flash will last
approximately 0.25 seconds, and each pause will last
approximately 2 seconds).
Monitored
LED Condition During Action
Solid On Normal All Times None required
1 Flash Ignition retries Heating Gas Valve “Off”
exceeded Demand Circulator
“Delay Off”
Inducer “Off”
2 Flashes PSW Stuck Heating All Outputs
Closed Demand “Off” except circ
Only cool speed in
response to a
call for fan/cool
3 Flashes PSW Stuck Heating All Outputs
Open Demand “Off” except circ
Only cool speed in
response to a
call for fan/cool
4 Flashes Limit Switch Heating Gas Valve “Off”
Open Demand Circulator “On”
Only Inducer “On”
5 Flashes Improper All Times Gas Valve “Off”
Flame Circulator “On”
Inducer “On”
Rapid Improper Power-up Gas Valve “Off”
Flashing Polarity Circulator “Off”
Inducer “Off”
Twinning All other Gas Valve “Off”
Fault times Circulator “Off”
Inducer “Off”
Off Internal error All Times Gas Valve “Off”
detected Circulator “Off”
Inducer “Off”
BLOWER
TIME OFF
JUMPER
90 120 150
STATUS
TWIN
W
G
R
STATUS
90 120 150 90 120 150 90 120 150
JUMPER SET
STATUS
JUMPER SET
STATUS
JUMPER SET
FOR 90 SEC. FOR 120 SEC. FOR 150 SEC.

5
HUM
IND
EAC
HSI
W
G
R
COOL
HEAT
NEUTRAL
TRNS
PRI
BLK
M2
M1
FS
LIMI
PSI
GV
TR
LIMO
90+0
TH
PSO
90+1
IGNITOR
R
G
W
THERMOSTAT
GAS
VALVE
HIGH LIMIT
(N. C.)
PRESSURE SWITCH (N. O.)
FLAME
SENSOR
PROBE
ELECTRONIC
AIR CLEANER
HUMIDIFIER
INDUCER
CIRCULATOR
BLOWER
50T35-743
24VAC
120VAC
24VAC CLASS II
TRANSFORMER
HOT
(LINE) NEUTRAL (LINE)
TH TR
LowVoltage (24 VAC)
LineVoltage (120VAC)
LEGEND
N. C. = Normally closed switch
N. O. = Normally open switch
TYPICAL SYSTEMWIRING DIAGRAM
TWIN*
TWIN*
50T35-743
in other
furnace(s)
—
TWINNING
APPLICATIONS
ONLY
*The twinning feature is available only on models with
six screw terminals; one of these terminals will be
designated“TWIN”. All 50T35-743 controls used in
twinning applications must have the “TWIN” terminal.

50T35
TERMINAL TERMINAL TYPE SYSTEM COMPONENT CONNECTION
TYPICAL SYSTEM WIRING TABLE
3/16" spade
terminals
3/16" spade terminals
9-pin
connector
& harness
or edge
connector
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminals
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
1/4" spade terminal
W
G
R
TWIN*
90+1
PSO
TH
90+0
LIMO
TR
GV
PSI
LIMO
IND
HSI
EAC
HUM
COOL
HEAT
NEUTRAL (4 terminals)
FS
M1
M2
PRI
TRNS
BLK
low voltage thermostat W terminal (or equivalent)
low voltage thermostat G terminal (or equivalent)
low voltage thermostat R terminal (or equivalent)
one wire twinning terminal
option jumper for GMP and GMPV Series Units
pressure switch OUTPUT
24 VAC transformer (low voltage HIGH side)
option jumper for GMP and GMPV Series Units
high limit OUTPUT
24 VAC transformer (low voltage COMMON side)
gas valve
pressure switch INPUT
high limit INPUT
inducer HOT side
ignitor HOT side
electronic air cleaner HOT side
humidifier HOT side
circulator blower COOL SPEED terminal
circulator blower HEAT SPEED terminal
input voltage (120 VAC) NEUTRAL side and
NEUTRAL line connections
flame sensor probe
†
park
park
24 VAC transformer line voltage HOT side
24 VAC transformer line voltage NEUTRAL side
input voltage (120 VAC) HOT side
* All 50T35-743 controls used in twinning applications must have the “TWIN” terminal.
†
Maximum recommended flame probe wire length is 36 inches.
St. Louis, MissouriSt. Louis, Missouri
St. Louis, MissouriSt. Louis, Missouri
St. Louis, Missouri
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White-Rodgers is a division
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.