White Rodgers 21V51U-843 Integrated Furnace Controls Instruction Manual

: August 28, 2024
: WHITE RODGERS

Table of Contents

White Rodgers 21V51U-843 Integrated Furnace Controls
INTEGRATED FURNACE CONTROLS
MOUNTING AND WIRING
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White Rodgers 21V51U-843 Integrated Furnace Controls

INTEGRATED FURNACE CONTROLS

The 50V51-843 has only one serviceable part –an automotive-type fuse, which protects the low-voltage transformer from damage if the 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 50V51-843 control. There are no other user-serviceable parts. Following installation or replacement, follow the appliance manu-facturer’s recommended installation or service instructions to ensure proper operation.

50V51-843 TYPICAL SYSTEM WIRING DIAGRAM

50V51-843 TYPICAL SYSTEM WIRING TABLE

50V51-843 TERMINAL	TERMINAL TYPE	SYSTEM COMPONENT CONNECTION
W1		two-stage thermostat W1 terminal (or equivalent)
W2		two-stage thermostat W2 terminal (or equivalent)
G		two-stage thermostat G terminal (or equivalent)
R	9-screw	two-stage thermostat R terminal (or equivalent)
B/C	terminal	two-stage thermostat B/C terminal (or equivalent)

YLO

Y

| block| two-stage thermostat Y terminal (or equivalent)

two-stage thermostat Y2 terminal (or equivalent)

TH (5)

| ****

12-pin

| MUST BE RELIABLY GROUNDED TO CHASSIS

24 VAC transformer (low voltage HIGH SIDE)

IND HI (2)

| ****

5-pin

| ignitor HOT side

inducer HIGH SPEED HOT side

E2-10

| 16-pin connector & harness| adjust tap OUTPUT to circulator 24 VAC COMMON

“O” OUTPUT to circulator

Humidistat/Y-Y2 OUTPUT to Circulator Blower

OPTIONS SWITCHES
Option switches are used to determine the length of the delay periods. The following tables show the periods that will result from the various switch settings.

OPTION SWITCH SETTING – THERMOSTAT TYPE AND HEAT-FAN-OFF-DELAY

DIP Switches

Multi-stage Thermostat Set-up, Factory Default
DIP switches S7-1 and S7-2 (see table above) are set to the “Off” position from the factory for use with a multi-stage thermostat. This allows the thermostat to control staging between low and high fire.

Single Stage Thermostat Set-up, Module Controls Staging
DIP switches, S7-1 and S7-2 (see table above) configure for a single stage thermostat. Options include a 10-minute delay in the second stage, a 20-minute delay in the second stage, or an Auto setting allowing the module to calculate the time delay for the second stage based on average demand. The “Average Calculated Duty Cycle” table shows how the module calculates staging based on demand.

Average Calculated Duty Cycle

% Equals

| or is less than| Low to High Stage Delay| Demand
---|---|---|---
0| 38| 12 minutes| Light
38| 50| 10 minutes| Light to Average
50| 62| 7 minutes| Average
62| 75| 5 minutes| Average to Heavy
75| 88| 3 minutes| Heavy Light
88| 100| 1 minute| Heavy

Heat Fan Off Delay Timing DIP switches S7-3 and S7-4 (see table above) configure the number of seconds the blower will run after the call for heat ends. The factory default is 90 seconds.

OPTION SWITCH SETTING – FURNACE MANUFACTURER

DIP Switch Selection for OEM Applications

IMPORTANT: Switch selection must match the furnace manufacturer for proper motor operation. Set DIP switches S2-1 and S2-2 to match the equipment using the table above. NOTE: DIP switch S2-3 is not used.

DIP Switches

OPTION SWITCH SETTING – HEAT PUMP AND DE-HUMIDIFICATION

Heat Pump Systems
DIP switch S5-1 (see table above) is set to “On” from the factory for use with conventional (non-heat Pump systems). For heat pump systems move the S5-1 DIP switch to the “Off” position. This will continuously output an O signal to the motor whenever there is a Y signal and run the circulator blower at a constant speed when the pump is operating.

De-Humidification Connection
DIP switch S5-2 (see table above) is set to “On” from the factory for systems that do not have a dehumidification terminal connection from the thermostat. For systems using a thermostat that provides a De-Humidification option move DIP switch S5-2 to “Off”.

OPTION SWITCH SETTING – MOTOR OPTIMIZATION
Amana/Goodman/Trane/Lennox/Thermo Pride – The motor conﬁguration DIP switches S3 and S4 must be set to match the settings of the original furnace settings for proper motor function. To set the new board for the motor function, the DIP switches must be set to match the settings of the board being replaced.

IMPORTANT: Be sure to use proper switches for new board settings. Switch locations on the old board may not be the same location as on the new board.

York – The existing board has four shunt jumper banks to set motor function conﬁguration. The four jumper banks are designated DELAY (E45), COOL (E43), HEAT (E46), and ADJ. (E44). Each jumper bank has four pairs of pins to have the jumper installed to determine the type of voltage to the motor. These pin pairs are A (no signal) B ( positive Half-wave rectiﬁed), C (negative Half- wave rectiﬁed), and D (Full-wave unrectiﬁed). On the new board, the motor functions must be duplicated on DIP switched S3 and S4 per the following table.

Motor Conﬁguration Settings

| | A

No Signal

| B

Positive

Half Wave

| C

Negative

Half Wave

| D

Full

Wave

---|---|---|---|---|---
Cool| S3- 1| OFF| ON| OFF| ON
S3- 2| OFF| OFF| ON| ON
Adjust| S3- 3| OFF| ON| OFF| ON
S3- 4| OFF| OFF| ON| ON
Delay| S4- 1| OFF| ON| OFF| ON
S4- 2| OFF| OFF| ON| ON
Heat| S4- 3| OFF| ON| OFF| ON
S4- 4| OFF| ON| ON| ON

NORMAL OPERATION – HEAT ON
When the thermostat calls for heat the module veriﬁes the pressure switches are open and energizes the inducer (high speed) and optional humidiﬁer contacts. When the low-pressure switch contacts close a 15-second pre-purge begins. After 15 seconds the inducer switches to low speed and the 120 VAC ignitor is energized. The ignitor warms up for 17 seconds and the gas valve is energized on low ﬁre. Flame must be detected within 4 seconds. If ﬂame is detected, a 45-second heat, fan on time delay begins. This allows the heat exchanger to warm up before energizing the circulator on low speed and (optional) Electronic Air Cleaner contact. When the thermostat (or module) initiates the second stage the inducer is energized at high speed.
This closes the second stage inducer pressure switch then energizes the second stage on the gas valve and then the high heat circulator speed.

NORMAL OPERATION – HEAT OFF
When the thermostat satisﬁes for the second stage, the control will switch the high-speed inducer and high ﬁre gas valve to a low-speed inducer and low ﬁre gas valve. After the 30-second high heat fan delay the circulator will drop to low speed. When the thermostat satisﬁes for ﬁrst stage the gas valve de- energizes and the inducer will run at low speed for a 15-second post-purge. The circulator runs until the heat-off delay ends.

Note: If the module is conﬁgured for a single-stage thermostat and running on the second stage when the call for heat ends, the circulator will drop to low speed after 30 seconds and continue until the heat-off delay ends.

COOL MODE
In a typical system, a call for cooling is initiated by closing Y and G. This energizes the compressor and the electronic air cleaner (optional). The electronic air cleaner and the G and (Y or YLO outputs to the Circulator motor will energize after the 5-second cool delay period. After the thermostat is satisﬁed, the compressor is de-energized and the control starts a 60-second cool circulator speed-off delay. After 60 seconds the circulator is de- energized.

MANUAL FAN ON MODE
If the thermostat fan switch is moved to the “ON” position, the electronic air cleaner (optional) and the G circulator output to the circulator motor will be energized. When the fan switch is returned to the AUTO position, the G circulator output and the electronic air cleaner are de-energized.

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 50V51 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 the 50V51 speciﬁcation sheet for recom-mended 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 the 50V51 speciﬁcation sheet for recommended terminals to mate with those on the control.

GOODMAN NOTE

FOR THE GOODMAN 50V51-289 APPLICATION, THERE IS THIS PACKAGE TO COMPLETE THE INSTALLATION.

The 50V51-843 has only one serviceable part –an automotive-type fuse, which protects the low-voltage transformer from damage if the 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 does not correct the condition, replace the entire 50V51 control. There are no user-serviceable able parts. Following installation or replacement, follow the appliance manufacturer’s recommended installation or service instructions to ensure proper operation.

INSTALLER MUST READ FOR PROPER INSTALLATION

Wiring harnesses are included to complete the installation of the “UNIVERSAL 50V51-843” for Goodman applications.
For replacing the ignitor, a UNIVERSAL 21D64-2 is included. For proper installation, refer to the instructions included in the 21D64-2 kit.
IMPORTANT: The installer may have to enlarge the existing ignitor hole to accommodate 2the 1D64-2 larger (.394”) diameter.

SYSTEM LOCKOUT
When a system lockout occurs (1 hour), the gas valve is energized, the low- speed inducer blower is energized for the 60 second interpurge period and the circulator is energized for selected heat-off delay if it was previously ON. The diagnostic indicator light will flash the fault that is present (refer to diagnostic table).

To reset the control after system lockout, do one of the following:

System Reset
Remove 24 VAC power to the control for twenty (20) seconds or longer to reset the control.

Thermostat Reset
Remove the call for heat from the thermostat for a period of between (1) second and less than 20 seconds. If ﬂame is sensed with the gas valve de- energized, interrupting the call for heat at the thermostat will not reset the control.

Auto Restart
After one (1) hour of internal or external lockout, the control will automatically reset itself and go into an auto restart purge for 15 seconds.

DIAGNOSTIC FEATURES
The control continuously monitors its operation and the op-eration of the system. If a failure occurs the diagnostic indicator LED (DSI) will ﬂash a “RED” failure code. If a failure is internal to the control the “RED” indicator will stay on continuously. In this case, the entire control should be replaced as the control is not ﬁeld-repairable. If the LED is continuously OFF, there may be no power to the control or a failure within the con-trol. If the sensed failure is in the system (external to the control), the LED will ﬂash RED in the sequence listed in the Diagnostic Table. The LED will also indicate “System Status” as per the Amber and Green LED signatures listed in the Diagnostic Table. The LED will ﬂash one RED ﬂash at power up.

CFM INDICATOR
The LED (DS2) CFM ﬂashes when the blower motor is running. The ﬂashing indicates the motor CFM (cubic feet per minute) air ﬂow designated by the furnace manufacturer. Consult the furnace manufacturer for ﬂash code details.

FAULT CODE RETRIEVAL
To retrieve fault codes, push and release the “LAST ERROR” button for more than 1/5 second and less than 5 seconds. (Con-trol will indicate this period by solid GREEN for 1/5 secs. to 5 secs.). The LED will ﬂash up to ﬁve stored fault codes, beginning with the most recent. If there are no fault codes in memory, the LED will ﬂash two green ﬂashes. The control will ﬂash the most recent error ﬁrst and the oldest error last (last in ﬁrst out). There shall be 2 seconds between codes. Solid LED error codes will not be displayed.

NOTE
These error codes may be different from the furnace label or furnace manual.

TRI-COLOR (DSI LED) DIAGNOSTIC TABLE

Green LED

Flash

| Amber LED

Flash

| Red LED Flash| Error/Condition| Comments/Troubleshooting
---|---|---|---|---
| | 1| Flame sensed when no flame should be

present

| Verify the gas valve is operating and shutting down properly. The flame in the burner assemble should extinguish promptly at the end of the cycle. Check orifices and gas pressure.
| | 2| Pressure switch stuck closed/ inducer error| The pressure switch stuck closed. Check the switch function, and verify inducer is turning

off.

| | 3| 1st-stage pressure switch stuck open/

inducer error

| Check the pressure switch function and tubing. Verify inducer is turning on the pulling sufficient vacuum to engage the switch.
| | 4| Open limit switch| Verify continuity through the rollout switch circuit.
| | 5| Open rollout/open fuse detect| Verify continuity through the rollout switch circuit, and check the fuse.
| | 6| 1st-stage pressure switch cycle lockout| If the first stage pressure switch cycles 5 times (open, closed) during one call for heat from the thermostat the control will lockout. Check the pressure switch for fluttering, inconsistent closure, or poor vacuum pressure.
| | 7| External lockout (retries exceeded)| Failure to sense flame is often caused by carbon deposits on the flame sensor, a disconnected or shorted flame sensor lead, or a poorly grounded furnace. Carbon deposits can be cleaned with an emery cloth. Verify sensor is not contacting the burner and is located in a good position to sense flame. Check the sensor lead for shorting and verify furnace is grounded properly.
| | 8| External lockout (ignition recycles exceeded where the flame is established and then lost)| Check items for exceeded retries listed above and verify valve is not dropping out allowing the flame to be established and then lost.
| | 9| Grounding or Reversed polarity| Verify the control and furnace are properly grounded. Check and reverse

polarity (primary) if incorrect.

| | 10| Module gas valve contacts energized with no call for heat| Verify valve is not receiving voltage from a short. If a valve wiring is correct and the condition persists, replace the module.
| | 11| Limit switch open – possible blower failure overheating limit| Possible blower failure restricted airflow through appliance or ductwork.

Verify continuity through the limit switch circuit and correct overheating cause.

| | 12| Module Ignitor contact failure| The fault code indicates the module ignitor contacts are not functioning properly. Replace module.
| | Solid| Module – internal fault condition| Module contacts for gas valve not operating or processor fault. Reset control. if the condition persists replace the module.
| | 3 double| 2nd-stage Pressure Switch Stuck Open/

Inducer Error

| Check the pressure switch function and tubing. Verify inducer is turning on and pulling sufficient vacuum to engage the switch.
| 1| | Normal Operation with a call for the first stage

heat

| Normal operation – first stage
| 2| | Normal Operation with a call for second-stage heat| Normal operation – first stage
| 3| | W2 present with no W1| The second stage calls for heat on the thermostat circuit with no call for the first stage. Verify DIP switches are set for a two-stage thermostat and check the thermostat first-stage circuit. Configured for a multi-stage thermostat the Module will not initiate heating unless the first stage call from the thermostat is received.
| 4| | Y present with no G call| The module will allow cooling to operate with only a “Y signal from the thermostat but will also trigger this code. Verify thermostat is energizing both “Y” and “G” on call for cool. Check “G” terminal connections.
| Rapid| | Low flame sense current| The low flame sense current is often caused by carbon deposits on the flame sensor, a poorly grounded furnace, or a misaligned flame sense probe. Carbon deposits can be cleaned with an emery cloth. Check for improved furnace and module ground. Verify sensor is located in or very near the flame as specified by the appliance manufacturer.
1| | | Standby or Call for Cool| Normal operation. Waiting for a call from the thermostat or receiving a thermostat call for cool.