White Rodgers 50V64-743 User manual

Application of this type of control may cause flame
rollout on initial startup 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 volt-
age, 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.
50V64-743
Integrated Furnace Control
for Furnaces with Variable Fan Speed
INSTALLATION INSTRUCTIONS
Operator: Save these instructions for future use!
FAILURETO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE
INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL
INJURY AND/OR PROPERTY DAMAGE.
CONTENTS
Description ............................................................. 1
Precautions ............................................................ 1
Specifications ......................................................... 2
Operation................................................................ 2
Installation .............................................................. 5
Mounting & Wiring
The 50V64-743 is a two-stage automatic gas interrupted ignition
control employing a microprocessor to continually monitor,
analyze, and control the proper operation of the gas burner and
inducer, and provide signal for proper operation of variable fan
speed timing.
Signals interpreted during continual surveillance of the two-
stage thermostat and flame sensing element initiate automatic
ignition of the burner, sensing of the flame, and system shutoff
during normal operation.
The control incorporates system fault analysis for quick gas
flow shutoff, coupled with automatic ignition retry upon sensing
a fault correction.
PART NO. 37-7565A
1503
www.white-rodgers.com
www.emersonclimate.com
DESCRIPTION
PRECAUTIONS
GENERAL PRECAUTION
!
To prevent electrical shock and/or equipment damage,
disconnect electric power to system at main fuse or
circuit breaker box until installation is complete.
This control is not intended for use in locations where
it may come in direct contact with water. Suitable
protection must be provided to shield the control from
exposure to water (dripping, spraying, rain, etc.).
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation.
Following installation or replacement,follow appliance
manufacturers’ recommended installation/service
instructions to insure proper operation.
Do not use on circuits exceeding specified voltage.
Higher voltage will damage control and could cause
shock or fire hazard.
CAUTION
!
WARNING
!
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.

2
SPECIFICATIONS
OPERATION
OPTION SWITCHES
Switches on the 50V64-743 control are used to control functions
of the circulator blower. Switches labeled SW3 and SW4 control
the circulator blower speed. Switch labeled SW2 controls the
heat delay-to-fan-off period. The following table shows the time
periods that will result from the various switch positions.
50V64
TIMING SPECIFICATIONS
(All times are in seconds, unless noted otherwise)
PRE-PURGE
TRIAL FOR IGNITION
PERIOD
IGNITION ACTIVATION
PERIOD
RETRIES
VALVE SEQUENCE PERIOD
INTERPURGE
POST-PURGE
LOCKOUT TIME
HEAT DELAY-TO-FAN ON
HEAT DELAY-TO-FAN OFF*
COOL DELAY-TO-FAN OFF*
ELECTRONIC AIR
CLEANER
HUMIDIFIER
0
5
2
2 times
15
60
5
258
45
60/100/
140/180
N/A
YES
YES
* These times will vary depending on option
switch position. See OPERATION section
for further information.
ELECTRICAL RATINGS [@ 77°F (25°C)]:
Input Voltage: 25 VAC, 60 Hz
Max. Input Current @ 25 VAC: 525mA + MV
Relay Load Ratings:
Gas Valve Relay: 1.5 amp @ 25 VAC, 60 Hz, 0.6 pf
Ignitor: 2.0 amp @ 80VAC, 60 Hz - resistive
Humidifier Relay: 1.0 Amp @120 VAC, 60 Hz.
Electronic Air Cleaner Relay: 1.0 Amp, @ 120 VAC, 60 Hz
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 95% relative humidity (non-condensing)
Timing Specs: (@ 60 Hz**)
maximum
Flame Establishing Time: 0.8 sec
Flame Failure Response Time: 2.0 sec
Gases Approved: Natural, Manufactured, Mixed, Liquid
Petroleum, and LP Gas Air Mixtures are all approved for
use.
SW1 SWITCH POSITIONS
Set switch #
SW1-2
Off
On
Off
On
TIME SW1-1
Set switch #
On
Off
Off
On
1/2 Min
5 Min
10 Min
15 Min
OPTION SWITCH POSITIONS
HEAT delay-
to-fan-off (SW2):
Set switch #
1
On
On
Off
Off
2
Off
On
On
Off
60 sec.
100 sec.
140 sec.
180 sec.
The dip switch settings for this control may be different from the
control being replaced. Please set the switches for the delay
period according to the chart above.
If W1 and W2 are tied together, the time delay of second stage
is based on the switch settings of SW1, per the following table.

3
HEAT MODE
In a typical system, a call for first stage heat is initiated by
closing the W1 thermostat contacts. The Humidifier output is
energized and the inducer blower is enabled at low speed. The
control waits for the stage 1 pressure switch to close. When
the pressure switch closes the silicon nitride ignitor is powered.
This control has an adaptive algorithm that reduces the ignitor
temperature to slightly greater than the minimum temperature
required to ignite gas in each particular application. The con-
trol measures the line voltage and determines an initial ignitor
temperature setting based on the measurement. After each
successful ignition, the control lowers the ignitor temperature
slightly for the next ignition attempt. The control continues to
lower the ignitor temperature until ignition does not occur, and
the control goes into retry mode. For the second attempt to
ignite gas within the same call for heat, the control increases
the ignitor temperature to the value it was on the previous
successful ignition. After ignition is successful, the control sets
the ignition temperature at this value. The control is constantly
making adjustments to the ignitor modulation routine to com-
pensate for changes in the line voltage. The control will relearn
after power interruptions.
The Silicon Nitride ignitor manufactured by White-Rodgers
must be used.These ignitors are specially designed to operate
with the adaptive ignition routine used by the control to ensure
the most efficient ignitor temperature.
At the end of the ignitor warm-up time, the first stage of the two-
stage manifold gas valve is energized (low fire). Flame must be
detected within 5 seconds. If flame is detected, the 45 second
delay-to-fan-on period begins. After the delay-to-fan-on period
ends, the circulator enable, (pin 15 on the 16-pin connector is
the “E” output to the circulator) and air cleaner are energized.
A call for second stage heat (W1 and W2) after a call for first
stage heat will activate a 30-second 2nd stage delay. Following
the 30-second delay, the inducer motor is driven at high speed.
The control checks the 2nd stage pressure switch. When the
pressure switch closes, the 2nd stage gas valve turns on and
the circulator is enabled at high speed (“E” remains energized
any time the circulator is on).
When the second stage of the thermostat is satisfied, the inducer
motor is reduced to low speed, and the 2nd stage gas valve and
high circulator speed are de-energized.
When the first stage of the thermostat is satisfied, the gas valve
is de-energized and the heat delay-to-fan-off timing begins.The
inducer will postpurge for an additional 5 seconds. When this
time is expired, the inducer and humidifier will de-energize.Upon
completion of the heat delay-to-fan-off period, the circulator and
air cleaner are de-energized.
If flame is not detected during the trial-for-ignition period, the gas
valve is de-energized, the ignitor is turned off, and the control
goes into the “retry” sequence.
The “retry” sequence starts with a 60-second interpurge, en-
abling the inducer at low speed for 60 seconds following an
unsuccessful ignition attempt (flame not detected). After this
wait, the ignition sequence is restarted. If this ignition attempt
is unsuccessful, one more retry will be made before the control
goes into system lockout.
If flame is detected, then lost, the control will repeat the initial ig-
nition sequence for a total of ten “recycles”.After ten unsuccessful
attempts to sustain flame, the control will go into system lockout.
During burner operation, a momentary loss of power of 250
milliseconds or longer will de-energize the main gas valve.When
power is restored, the gas valve will remain de-energized and a
restart of the ignition sequence will begin immediately.
A momentary loss of gas supply, flame blowout, or a shorted or
open condition in the flame probe circuit will be sensed within
2 seconds. The gas valve will de-energize and the control will
restart the ignition sequence.Recycles will begin and the burner
will operate normally if the gas supply returns, or the fault con-
dition is corrected, before the last ignition attempt. Otherwise,
the control will go into system lockout.
If the control has gone into system lockout, it may be possible
to reset the control by a momentary power interruption of five
seconds or longer. Refer to PRECAUTIONARY, SYSTEM
LOCKOUT, AND DIAGNOSTIC FEATURES.
COOL MODE
In a typical system, a call for cool is initiated by closing the
thermostat contacts. This energizes the compressor, circulator
“E” output and air cleaner. After the thermostat is satisfied, the
compressor is de-energized and the optional cool mode delay-
to-fan-off period begins.After the optional delay-to-fan-off period
ends, the circulator “E” output and air cleaner are de-energized.
MANUAL FAN ON MODE
If the thermostat fan switch is moved to the ON position, the
circulator “E” output and air cleaner are energized. When the
fan switch is returned to the AUTO position, the circulator “E”
output and air cleaner are de-energized.
PRECAUTIONARY, SYSTEM LOCK-
OUT, AND DIAGNOSTIC FEATURES
PRECAUTIONARY FEATURES
The following precautionary features are built into the control.
1. If the high temperature limit or flame rollout sensor open
at any time, the gas valve is de-energized.
2. During a call for heat cycle, if flame is sensed at any time
when the gas valve is de-energized, the circulation “E”output
and inducer fan are energized at low speed in conjunction
with system lockout.
3. If the high limit (and/or auxiliary limit) switch(es) open at
any time during a call for heat, the circulator blower and
inducer fan are energized at low speed.
SYSTEM LOCKOUT FEATURES
When system lockout occurs, the gas valve is de-energized, the
circulator “E” output and the inducer blower are energized at low
speed.The diagnostic indicator light will flash to indicate system
status.(System lockout will never override the precautionary
features described above.)
To reset the control after system lockout, do one of the
following:
1. Interrupt the call for heat at the thermostat for at least one
second and less than twenty seconds (if flame is sensed
OPERATION

4
MOUNTING AND WIRING
INSTALLATION
All wiring should be installed according to local and national
electrical codes and ordinances.
The 50V64 control may be mounted on any convenient surface
using the four standoffs provided.
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 50V64 control to other components of the system.
UL approved, 105°C rated 18 gauge min., stranded,²/64" thick
insulation wire is recommended for all low voltage safety circuit
connections. Refer to 50V64 control 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 50V64 control specification sheet for recommended
terminals to mate with those on the control.
Following installation or replacement, follow appliance
manufacturer’s recommended installation or service instructions
to insure proper operation.
5 flashes, then pause Flame sense when no flame
should be present
6 flashes, then pause Line reverse polarity or ignitor
circuit error
7 flashes, then pause Gas valve circuit error
8 flashes, then pause Weak flame
9 flashes, then pause Open inducer limit error
The Green and Red LED's will also flash once for 1 second at
power-up.
FAULT CODE RETRIEVAL
Two seconds after the power ON, the control shall flash the last
four error codes that have occurred over the last 14 days on
the red LED. The control will flash the newest error first and the
oldest error last with a two-second pause between flash codes.
Solid LED error codes will not be displayed.The green STATUS
LED shall remain ON while the red LED flashes the error codes.
The last four fault codes can be erased from memory by pow-
ering up with Genergized and then toggling W1 three times
within eight seconds. W1 must be toggled after the power ON
reset for approximately one second each time. The control will
acknowledge by turning on the red LED and green STATUS
LED for two seconds.
with the gas valve de-energized, interrupting the call for
heat at the thermostat will not reset the control).
2. Interrupt the 24 VAC power at the control for at least five
seconds.You may also need to reset the flame rollout sensor
switch.
3. After one hour in lockout, the control will automatically reset
itself.
DIAGNOSTIC FEATURES
The control continuously monitors its own operation and the
operation of the system. If a failure occurs, the red LED on the
control will flash a failure code. If the Red and Green "status"
LED's are on solid, the 5 amp replaceable fuse is bad. If the
fuse is good or the Red LED is on by itself, the entire control
should be replaced, as the control is not field-repairable.
If the sensed failure is in the system (external to the control),
the red 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).
2 flashes, then pause Retries or recycles exceeded
3 flashes, then pause Inducer or pressure switch
error
4 flashes, then pause Open limit or rollout switch
Do not use on circuits exceeding specified voltage.
Higher voltage will damage control and could cause
shock or fire hazard.
WARNING
!
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.
Replace 50V50 control as a unit - no user serviceable
parts.
NOTE
OPERATION

5
50V64 TERMINAL TYPE SYSTEM COMPONENT CONNECTION
LINE Input voltage (120 VAC) HOT SIDE
XFMR-H
spade terminal*
24 VAC transformer line voltage neutral side
Input voltage (120 VAC) neutral side
spade terminal*
24 VAC Common
Low heat speed select, output to circulator blower
24 VAC Common
Delay tap, output to circulator
Cool tap, output to circulator
YLO, output to circulator
Adjust tap, output to circulator
24 VAC Common
O, output to circulator
Humidistat, output to circulator
Heat tap, output to circulator
24 VAC
W2, output to circluator
Y, output to circulator
G, output to circulator
G reen CFM indicator
spade terminal* Circulator blower neutral side
CIR-H
CIR-N
XFMR-N
FP
HUM - N
EAC - N
EAC
HUM
LINE-N
spade terminal* 24 VAC transformer line voltage hot side
spade terminal*
spade terminal*
spade terminal*
spade terminal*
spade terminal*
spade terminal*
spade terminal*
4-pin
connector
16-pin
connector
TYPICAL SYSTEM WIRING TABLE
Circulator blower hot side
Humidifier hot side
Electronic Air Cleaner hot side
Humidifier neutral side
Electronic Air Cleaner neutral side
Flame probe**
** maximum recommended flame probe wire length is 36 inches.
IND 01 (1)
IND 02 (2)
IND 03 (3)
GRND (4)
Inducer 01
Inducer 02
Inducer 03
Inducer ground
2-pin
connector
IGN-H
IGN-N
Ignitor output
Ignitor common
* Spade terminals are 0.25" x 0.032"
W1
W2
G
R
B/C
YLO
Y
BK
O
MVH (3)
MV COM (8)
HLI (2)
HLO (9)
TR (11)
MV (4)
TH (7)
GND (5)
PS2 (6)
PS0 (1)
IL1 (10)
PS1 (12)
E11-1
E11-2
E11-3
E11-4
E11-5
E11-6
E11-7
E11-8
E11-9
E11-10
E11-11
E11-12
E11-13
E11-14
E11-15
E11-16
First stage call for heat
Second stage call for heat
Input for fan operation
24 VAC transformer (HIGH side)
24 VAC transformer (LOW side)
First stage call for cool
Second stage call for cool
Humidistat enable
H/P or cooling mode
Gas valve second stage
Gas valve ground
High limit input
High limit output
24 VAC transformer (low voltage COMMON side)
Gas valve first stage
24 VAC transformer (low voltage HIGH side)
MUST BE RELIABLY GROUNDED TO CHASSIS
2nd stage pressure switch
Pressure switch output
Inducer limit input
1st stage pressure switch
12-pin
connector
9-screw
terminal block

6
TH
TR
MV
MVH
MVC
PS-1
PS-2
PS-C
GND
HLI
HLO
IND-L
G
W2
W1
Y
YLO
O
B/C
BK
R
IND-03
IND-GND
IND-02
IND-01
LINE
FP
XFMR-H
CIR-H
CIR-N
LINE-N
XFMR-N
HUM-N
IGN-N
EAC-N
EAC
IGN-H
HUM
IGNITOR
YLO
Y
W1
W2
G
R
THERMOSTAT
GAS
VALVE
HIGH LIMIT
(N. C.)
PS1
(N. O.)
PS2 (N. O.)
ROLLOUT
(N. C.)
Inducer Limit
(N. C.)
FLAME
SENSOR
PROBE
CONDENSING
UNIT
CIRCULATOR
INDUCER
24 VAC
120 VAC
24 VAC CLASS II
TRANSFORMER
HOT
(LINE)
NEUTRAL
(LINE)
TH TR
Low Voltage (24 VAC)
Line Voltage (120 VAC)
LEGEND
N. C. = Normally closed switch
N. O. = Normally open switch
TYPICAL SYSTEM WIRING DIAGRAM
CIRCULATOR INTERFACE
ELECTRONIC
AIR CLEANER HUMIDIFIER
INTEGRATED FURNACE CONTROL
Field
Input

7
NOTES

White-Rodgers is a business
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.
www.white-rodgers.com
www.emersonclimate.com

Mouser Electronics
Authorized Distributor
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50V64-743