White Rodgers 50A56-956 Installation Instructions
Contents
1. 2 Connectthe TWIN terminals on the controls of the furnaces to be twinned to each other using a single wire 14 22 AWG 3 Both controls must be of the same model and type for the twinning feature to work properly SYSTEM LOCKOUT SYSTEM LOCKOUT FEATURES When system lockout occurs the gas valve is de energized the circulator blower is energized at heat speed and if flame is sensed the inducer blower is energized The diagnostic indicator light will flash or glow continuously to indicate system status System lockout will never override the precautionary features OPERATION To reset the control after system lockout do one of the following 1 Interruptthe call for heat or cool at the thermostat for at least one second but 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 2 Interrupt the 24 VAC power at the control for at least one second 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 50A56 956 control continuously monitors its own operation and the operation of the system If a failure occurs the LED will indicate a failure code as shown in the TROUBLESHOOTING If the failure is internal to the control the LED will stay on solid In this case the entire control should be replaced as the control is2. MANUAL FAN ON MODE If the thermostat fan switch is moved to the ON position the optional electronic air cleaner and circulator fan are energized The circulator speed is selectable via shunt jumper option E33 Three choices that can be made are Lo Cool Heat or Hi Cool By moving the shunt jumper location the desired continuous fan speed will be attained When the fan switch is returned to the AUTO position the circulator fan and electronic air cleaner optional are de energized Manual Fan Speed Shunt Jumper E33 a a LOCOOL cont LO COOL u a LOCOOL m mjo a HEAT FAN 8 o HEAT a uj HEAT H cooL SPEED a a HICOOL a al HICOOL Factory Setting LO COOL HEAT HI COOL TWINNING INTERFACE The control is equipped with a single wire twinning interface which is a 3 16 spade terminal designated as TWIN If twinning is used either control will process a call for heat cool or fan as described above However after the heat cool or fan on delay time expires both units will energize the circulator blowers at the same time Likewise after the heat cool or fan off delay time expires both units will de energize the circulator blowers at the same time This allows for proper air flow to be obtained To assure proper control operation both controls must share a common transformer ground TR To enable twinning do the following 1 Power supplied to both furnaces must be from the same phase of the 24 VAC power to the control
3. follow manufacturers recommended installation service instructions to ensure proper operation Do not short out terminals on gas valve or primary control Short or incorrect wiring may damage the thermostat Description Precautions Specifications Installation Mounting amp Wiring Operation Troubleshooting EMERSON DESCRIPTION 50A56 956 Cross Reference Information www white rodgers com www emersonclimate com York White Rodgers S1 33102956000 S1 03101266000 50A56 242 S1 03109167000 S1 03101284000 50A56 243 S1 03101933000 S1 03101973000 S1 03101267000 S1 03101972000 S1 03101267001 265901 S1 03100662000 265902 S1 03101250000 539617 S1 33103010000 PRECAUTIONS A WARNING mr ib Failure to comply with the following warnings could result in personal injury or property damage 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 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
4. complete the inducer blower and humidifier are de energized After the delay to fan off period ends the circulator fan and electronic air cleaner are de energized If flame is not detected both valves are de energized the ignitor is turned off and the control goes into the retry sequence The retry sequence provides a 15 second purge period following an unsuccessful ignition attempt flame not detected After this wait the ignition sequence is restarted with a 27 second ignitor warm up time The control will allow 2 retry periods before entering system lockout If flame is established for more than 10 seconds after ignition the controller will clear the ignition attempt or retry counter If flame is lost after 10 seconds it will restart the ignition sequence During burner operation a momentary loss of power of 50 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 0 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 condition is corrected If the control has gone into system lockout it may be possible to reset the control
5. White Rodgers 50A56 956 Integrated Furnace Control INSTALLATION INSTRUCTIONS FAILURETO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL INJURY AND OR PROPERTY DAMAGE The 50A56 956 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 ofthethermostat 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 Kit includes 1 Ignition Control 3 Install Sheet 2 Metal Control Box Installation should be done by a qualified heating and air conditioning contractor or licensed electrician Ifin doubtabout whether your wiringis millivolt line orlow 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
6. and line hot wires EXPLOSION HAZARD Shut off main gas to appliance until installation is complete PART NO 37 7475B Replaces 37 7475A 1419 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 OPERATING TEMPERATURE RANGE 40 to 176 F 40 to 80 C HUMIDITY RANGE 5 to 93 relative humidity non condensing MOUNTING Surface mount multipoise Timing Specs O 60 Hz maximum Flame Current Requirements Flame Establishing Time 0 8 sec Minimum current to insure flame detection 1 ya DC Flame Failure Response Time 2 0 sec Maximum current for non detection 0 1 ua DC Maximum allowable leakage resistance 100 M ohms Gases Approved Natural Manufactured Mixed Liquified Petroleum and LP Gas Air Mixtures are all approved for use Measured with a DC microammeter in the flame probe lead er At 50 Hz all timing specifications should be increased by 20 TIMING SPECIFICATIONS All times are in seconds unless noted otherwise Event Definition 50A56 956 Pre Purge The period of time intended to allow for the dissipation of any unburned 0 gas or residual products of c
7. at delay to fan off periods The following table shows the time periods that will result from the various positions Heat Delay to Fan Off Shunt Jumper E34 60 o ol 60 o o 60 o oj 90 wu 20 a aj 90 a oj 120 a of 120 a a 120 a al 180 o o 180 EN 180 60 Seconds 90 Seconds 180 Seconds Factory Setting 120 Seconds HEAT MODE In a typical system a call for heat is initiated by closing the Thermostat W contacts This starts the control s heating sequence The inducer blower and optional humidifier are energized After the pressure switch is proven the ignitor is energized and the warm up time begins The ignitor is allowed to warm up for a 17 seconds initial warm up The 120VAC ignitors with a 17 second warm up time must be used These ignitors are specially designed to heat up quickly at a low voltage condition without overheating at a high voltage condition At the end of the ignitor warm up time both valves in the manifold gas valve are opened Flame must be detected within 7 seconds When flame is detected the delay to fan on period begins After the 30 seconds delay to fan on period ends the optional electronic air cleaner is energized and the circulator fan is energized at heat speed When the thermostat is satisfied the gas valve is de energized After proof of flame loss the selectable heat delay to fan off period begins and the inducer blower remains energized to purge the system for 15 seconds When the purge is
8. by a momentary power interruption of one second or longer Refer to SYSTEM LOCKOUT FEATURES SINGLE STAGE COOL MODE In a typical single stage cooling system a call for cool is initiated by closing the thermostat contacts Y Y2 This energizes the control and the compressor The cool delay to fan on period begins After the delay period ends the optional electronic air cleaner is energized and the circulator fan is energized at high cool speed After the thermostat is satisfied the compressor is de energized and the cool mode delay to fan off period begins After the delay to fan off period ends the circulator fan and electronic air cleaner optional are de energized TWO STAGE COOLING MODE In a typical two stage cooling system a call for cool is initiated by closing the Y1 thermostat contacts This energizes the control and first stage of the compressor The cool delay to fan on period begins After the delay period ends the optional electronic air cleaner is energized and the low cooling circulator fan is energized When second stage cooling is called for the thermostat will energize Y Y2 This will energize the second stage of the compressor and high cooling speed of the indoor circulating fan After the thermostat is satisfied the compressor is de energized and the cool mode delay to fan off period begins After the delay to fan off period ends the circulator fan and electronic air cleaner optional are de energized
9. eposits on the flame sensor a disconnected or shorted flame sensor lead or a poorly grounded furnace Carbon deposits can be cleaned with emery cloth Verify sensor is not contacting the burner and is located in a good position to sense flame Ignitor must be positioned to light the gas immediately when the valve opens If the ignitor has been replaced verify hot spot position has not changed Check sensor lead for shorting and verify furnace is grounded properly Verify gas supply to valve gas valve in On position and appliance lighting properly Verify flame reaches flame sensor during ignition attempts and gas pressures are correct 8 External lockout recycles See above 9 Grounding or reversed Verify the control and furnace are properly grounded Check and polarity reverse polarity primary or secondary if incorrect 10 Gas flow with no call for Verify the gas valve is operating and shutting down properly heat Check gas valve wiring 11 Limit switch open blower Verify continuity through limit switch circuit Refer to wiring diagram failure terminals HLI HLO 12 Ignitor failure Open ignitor circuit indicated Check wiring or possibly a broken ignitor Solid Internal GV error micro Control failure Replace control and frequency check Rapid Twinning error incorrect Check that the 24V is phased correctly 24V phasing 4 Y present with no G call Check wiring from thermostat The control is not receiving a G call with a Y
10. not field repairable Failure codes will flash the LED 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 FAULT RECALL The last five fault codes stored can be displayed on the diagnostic LED When the control is in standby mode no call for heat or cool press the FAULT RECALL switch for approximately two to five seconds and release The fault codes will display beginning with the most recent fault first with a one second pause between codes After the stored fault codes have all displayed the LED will return to normal status While displaying the stored fault codes the control will ignore any new call for heat cool or fan If no fault codes are in memory the LED will flash two green flashes then return to normal status FAULT CODE RESET The stored fault codes can be erased from memory When the control is in standby mode no call for heat or cool press the FAULT RECALL switch for five to ten seconds or until the diagnostic LED begins to rapid flash When the switch is released the LED will flash three green flashes when memory has been cleared The 50A56 956 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 au
11. ntact 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 INSTALLATION Do not short out terminals on gas valve or primary control Short or incorrect wiring may damage the thermostat MOUNTING AND WIRING Certain upflow 9096 models may require the installation of the provided metal control mounting box The reuse of the existing door switch and transformer are required Other models may require new mounting holes In this case use the mounting tem plate located in figure 1 Specifically the BGU model furnaces may required not only new mounting holes but also relocation of the existing transformer In all cases the wiring connections will remain the same 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 controlis approved for minimum ambient
12. of of the supervised main burner flame 30 and the activation of the blower motor at Heat speed Heat Delay To Fan Off The period of time between the loss of a call for heat and the 60 90 120 180 deactivation of the blower motor at Heat speed Cool Delay To Fan On The period of time after a thermostat demand for cool before energizing 0 the circulator blower motor at Cool speed Cool Delay To Fan Off The period of time between the loss of a call for cool and the 60 deactivation of the blower motor at Cool speed Initial Ignitor Warm up The length of time allowed for the igniter to heat up prior to the initiation 17 of gas flow Ignitor Warm up Retries In the event of a retry the warm up time will be increased by one 27 second up to a maximum of 27 seconds and locked at that duration Auto Reset After one 1 hour of internal or external lockout the control will 60 minutes automatically reset itself and go into an auto restart purge for 60 seconds Electronic Air Cleaner Yes Humidifier Yes This time will vary depending on option switch position The control is factory set at 120 seconds HEAT delay to fan off See OPERATION section for further information A WARNING Ml E Failure to comply with the following warnings could result in personal injury or property damage FIRE HAZARD Do not exceed the specified voltage Replace existing control with exact model and dash number Protect the control from direct co
13. ombustion at the beginning of a furnace operating cycle prior to initiating ignition Trial for Ignition The period of time between initiation of gas flow and the action to 7 Period TFI shut off the gas flow in the event of failure to establish proof of the supervised ignition source or the supervised main burner flame Ignition Activation The period of time between energizing the main gas valve and 5 Period IAP deactivation of the ignition means prior to the end of TFI Retries The additional attempts within the same thermostat cycle for ignition 2 times when the supervised main burner flame is not proven within the first trial for ignition period Recycles The additional attempts within the same thermostat cycle for ignition 4 after loss of the supervised ignition source or the supervised main burner flame Valve Sequence Valve sequence period equals 7 seconds trial for ignition period x 21 Period 1 initial try 2 retries 12 seconds Interpurge The period of time intended to allow for the dissipation of any unburned 15 gas or residual products of combustion between the failed trial for ignition and the retry period Post Purge The period of time intended to allow for the dissipation of any unburned 15 gas or residual products of combustion at the end of a furnace burner operating cycle Post purge begins at the loss of flame sense Lockout Time ANSI standard rated module timing 140 Heat Delay To Fan On The period of time between pro
14. signal Slow Normal operation with call No fault for heat Rapid Low flame sense current Low flame sense current is often caused by carbon deposits on the flame sensor a poorly grounded furnace or a mis aligned flame sense probe Carbon deposits can be cleaned with emery cloth Check or improve furnace and module ground Verify sensor is located in or very near flame as specified by the appliance manufacturer Refer to wiring diagram FS terminal and GND NOTES NOTES 4 825 Note Confirm actual size of template before using Figure 1 Hole Template 11 TECHNICAL SUPPORT 1 888 725 9797 White Rodgers is a business Wh ite Rodgers A of Emerson Electric Co es The Emerson logo is a trademark and service mark www white rodgers com EM E RSO N of Emerson Electric Co www emersonclimate com
15. temperatures of 40 F Any orientation is acceptable Refer to the wiring diagram page 4 and wiring table page 5 when connecting the 50A56 control to other components of the system UL approved 105 C rated 18 gauge stranded 2 64 thick in sulation wire is recommended for all low voltage safety circuit connections UL approved 105 C rated 16 gauge min stranded 4 64 thick insulation wire is recommended for all line voltage connections After installation or replacement follow appliance manufactur er s recommended installation or service instructions to ensure proper operation HOT LINE TYPICAL SYSTEM WIRING DIAGRAM ELECTRONIC AIR CLEANER 50A56 in other furnace s TWINNING APPLICATIONS ONLY TWIN LEGEND Low Voltage 24 VAC Line Voltage 120 VAC N C Normally closed switch N O Normally open switch 120 VAC NEUTRAL LINE 24 VAC CLASS II TRANSFORMER CIRCULATOR BLOWER COMPRESSOR CONTACTOR THERMOSTAT PRESSURE SWITCH N O OD O HIGH LIMIT AUX HIGH N C LIMIT N C C ROLLOUT N C For two stage cooling mode only TYPICAL SYSTEM WIRING TABLE TERMINAL TYPE CONNECTION low voltage thermostat W terminal or equivalent low voltage thermostat G terminal or equivalent Terminal low voltage thermostat R terminal or equivalent block with low voltage thermostat Y terminal or equivalent captive 2nd wire from Y terminal goes to 24 VAC HOT side of Scre
16. tomotive type fuse If the fuse does not correct the condition replace the entire control There are no other user serviceable parts TROUBLESHOOTING Green Amber Red Error Condition Comments Troubleshooting LED LED LED Flash Flash Flash Slow Normal operation No fault 1 Flame sensed when no Verify the gas valve is operating and shutting down properly Flame flame should be present in burner assembly should extinguish promptly at the end of the cycle Check orifices and gas pressure 2 Pressure switch stuck Pressure switch stuck closed Check switch function verify inducer closed inducer error is turning off Refer to wiring diagram terminals PSI HLO 3 Pressure switch stuck Check pressure switch function and tubing Verify inducer is open inducer error turning on and pulling sufficient vacuum to engage switch Refer to wiring diagram terminals PS HLI 4 Open limit switch Verify continuity through limit switch circuit Refer to wiring diagram terminals HLI HLO 5 Open rollout switch open Verify continuity through rollout switch circuit Refer to wiring fuse detect diagram terminals ROSI ROS 6 Pressure switch cycle Check pressure switch function and tubing Verify inducer is pulling lockout sufficient vacuum to continuously engage switch Refer to wiring diagram terminals PS HLO 7 External lockout retries Failure to sense flame is often caused by carbon d
17. ws compressor contactor coil low voltage thermostat Y1 terminal or equivalent 24 VAC COMMON side of compressor contactor coil Pin 1 high limit OUTPUT Pin 2 flame sensor probet Pin 3 24 VAC transformer low voltage HIGH side Pin 4 Pin 5 rollout switch OUTPUT Pin 6 24 VAC transformer low voltage COMMON side HLI Pin 7 high limit INPUT GND Pin 8 MUST BE RELIABLY GROUNDED TO CHASSIS MV COM Pin 9 Main Valve Common PS Pin 10 pressure switch INPUT ROSI Pin 11 rollout switch INPUT MV Pin 12 gas valve IND Pin 1 inducer HOT side IGN Pin 2 ignitor HOT side IND N Pin 3 inducer NEUTRAL side IGN N Pin 4 i ignitor NEUTRAL side circulator blower LO COOL SPEED terminal circulator blower HI COOL SPEED terminal circulator blower HEAT SPEED terminal unused circulator blower terminal input voltage 120 VAC HOT side 24 VAC transformer line voltage HOT side electronic air cleaner HOT side 1 4 spade terminal humidifier HOT side circulator blower NEUTRAL terminal input voltage 120 VAC NEUTRAL side 24 VAC transformer line voltage NEUTRAL side electronic air cleaner NEUTRAL side 1 4 spade termina humidifier NEUTRAL side TWIN 1 4 spade terminal one wire twinning terminal H E Not Used bn P H R t Maximum recommended flame probe wire length is 36 inches OPERATION OPTION SWITCHES The shunt jumper E34 on the 50A56 control are used to determine the length of the he
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