G61MP Service Literature Corp. 0308−L6 Revised 10−2004 G61MP SERIES UNITS G61MP series units are high−efficiency multi−position (upflow, downflow, horizontal right and left) gas furnaces manufactured with Lennox Duralok Plust heat exchangers formed of aluminized steel. G61MP units are available in heating capacities of 44,000 to 132,000 Btuh (13.0.0 to 38.6 kW) and cooling applications from 2 to 5 tons (7.0 kW to 17.5 kW)) up to 5 tons. Refer to Engineering Handbook for proper sizing.
SPECIFICATIONS Gas H ti Heating Performance Model No. Input − Btuh (kW) Output − Btuh (kW) Temperature rise range − _F (_C) Input − Btuh (kW) Low Fi Fire Output − Btuh (kW) Temperature rise range − _F (_C) 1 AFUE California Seasonal Efficiency High static (CSA) − in. w.g. (Pa) 2 Intake Pipe (PVC) Connections 2 Exhaust Pipe (PVC) i in. Condensate Drain Trap (PVC pipe) − i.d. with field supplied (PVC coupling) − o.d. hose with hose clamp − i.d. x o.d. Gas pipe size IPS Wheel nominal diameter x width − in.
SPECIFICATIONS Gas H ti Heating Performance Model No. Input − Btuh (kW) High g Fire Output − Btuh (kW) Temperature rise range − _F (_C) Low Fire Input − Btuh (kW) Output − Btuh (kW) G61MP−60C−110 110,000 (32.2) G61MP−60D−135 132,000 (38.7) 104,000 (30.5) 104,000 (30.5) 124,000 (36.3) 45 − 75 (25 − 42) 35 − 65 (21 − 39) 40 − 70 (24 − 42) 75,000 (22.0) 75,000 (22.0) 90,000 (26.4) 72,000 (21.1) 72,000 (21.1) 86,000 (25.2) 30 − 60 (18 − 36) 25 − 55 (14 − 31) 30 − 60 (18 − 36) 1 AFUE 94.
BLOWER DATA G61MP−36B−045 PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds External Static Pressure in. w.g. 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.
BLOWER DATA G61MP−60C−090 PERFORMANCE (Less Filter) − Single Side Return Air − Air volumes in bold require field fabricated transition to accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) air filter in order to maintain proper air velocity. Air Volume / Watts at Different Blower Speeds External Static Pressure in. w.g. 0.00 Pa 0 Medium−High High cfm 2835 L/s 1335 Watts 1495 cfm 2340 L/s 1105 Medium−Low Low Watts 1155 cfm 1800 L/s 850 Watts 895 cfm 1440 L/s 680 Watts 695 0.
BLOWER DATA G61MP−60C−110 PERFORMANCE (Less Filter) − Bottom Return Air, Side Return Air with Optional RAB Return Air Base, Return Air from Both Sides or Return Air from Bottom and One Side. Air Volume / Watts at Different Blower Speeds External Static P Pressure in. w.g. 0.00 Pa 0 Medium−High High Medium−Low Low cfm 2720 L/s 1285 Watts 1385 cfm 2410 L/s 1135 Watts 1090 cfm 2055 L/s 970 Watts 935 cfm 1620 L/s 765 Watts 710 0.
G61MP PARTS ARRANGEMENT TOP CAP DuralokPlusTM HEAT EXCHANGER ASSEMBLY CABINET BURNER BOX ASSEMBLY GAS VALVE AND MANIFOLD FLUE COLLAR COMBUSTION AIR PROVE PROVE SWITCHES* WARM HEADER (COLLECTOR) BOX COMBUSTION AIR INDUCER CONDENSER COIL BURNER ACCESS PANEL PRIMARY LIMIT COLD HEADER (COLLECTOR) BOX BLOWER ACCESS DOOR *G61MP−090 shown. G61MP−045 and −070 are equipped with two switches.
I−UNIT COMPONENTS 3. Circuit Breaker (CB8) G61MP unit components are shown in figure 1. The gas valve, combustion air inducer and burners can be accessed by removing the burner access panel. Electrical components are in the control box (figure 2) found in the blower section. G61MP units are factory equipped with a bottom return air panel in place. The panel is designed to be field removed as required for bottom air return. Markings are provided for side return air and may be cut out in the field.
onds. After a total of five trials for ignition (including the initial trial), the control goes into Watchguard−Flame Failure mode. After a 60−minute reset period, the control will begin the ignition sequence again. The SureLight control board has an added feature that prolongs the life of the ignitor. After a successful ignition, the SureLight control utilizes less power to energize the ignitor on successive calls for heat.
TABLE 3 TWO−STAGE INTEGRATED CONTROL BOARD Integrated Control Board Terminals 120VAC Neutral LINE LEDs DIP SWITCHES 1−4 Line XFMR Transformer EAC Electronic Air Cleaner CIRC Indoor Blower HUM Humidifier 120VAC Line W915 FACTORY INSTALLED JUMPER (MUST CLIP FOR 2 STAGE COOL) HUM Humidifier XMFR Transformer LINE Line PARK For Unused Leads COOL Cooling Speed EAC Electronic Air Cleaner HI HEAT HIigh Heat Speed LO HEAT Low Heat, Low Cool and Continuous Fan Speed TABLE 4 Integrated C
TABLE 6 DIAGNOSTIC CODES Diagnostic LEDs are labeled DS1 and DS2. See figure 4 for location of diagnostic LEDs. DS1 DS2 SIMULTANEOUS SLOW FLASH SIMULTANEOUS FAST FLASH SIMULTANEOUS SLOW FLASH SIMULTANEOUS FAST FLASH DESCRIPTION SLOW FLASH ON OFF SLOW FLASH OFF FAST FLASH High prove switch open; OR: Blocked inlet/exhaust vent; OR: High prove switch closed prior to activation of combustion air inducer.
C−Heating Components 3. Flame Sensor 4. Ignitor A flame sensor is located on the left side of the burner support. See figure 6. The sensor is mounted through the bottom of the burner box and the tip protrudes into the flame envelope of the left−most burner. The sensor can be removed for service without removing any part of the burners. During operation, flame is sensed by current passed through the flame and sensing electrode.
6. Clamshell Heat Exchanger G61MP units use an aluminized steel primary and stainless steel secondary heat exchanger assembly. Heat is transferred to the air stream from all surfaces of the heat exchanger. The shape of the heat exchanger ensures maximum efficiency. The combustion air inducer pulls fresh air through the air intake box. This air is mixed with gas in the burner venturi and at the corbel orifices. The gas / air mixture is then burned at the entrance of each clamshell.
On heat demand (first or second stage) the switch senses that the combustion air inducer is operating. It closes a circuit to the furnace control when pressure inside the cold end header box decreases to a certain set point. Set points vary depending on unit size. See tables 8, 9 and 10. The pressure sensed by the switch is negative.
TABLE 8 0’ to 4500’ 12. Combustion Air Inducer (B6) All G61MP units use a combustion air inducer to move air through the burners and heat exchanger during heating operation. The blower uses a PSC 120VAC motor. The motor operates during all heating operation and is controlled by the ignition control A3. Blower operates continuously while there is a call for heat. The burner ignition control will not proceed with the ignition sequence until combustion air inducer operation is sensed by the proving switches.
II−PLACEMENT AND INSTALLATION TABLE 11 OUTDOOR TERMINATION KITS AND CORRESPONDING EQUIVALENCIES Vent Pipe Length Equivalency (feet) UNIT MODEL Outdoor Exhaust Accelerator (Dia. X Length) Outdoor Exhaust Accelerator (Dia.
A−Vent Piping Guidelines The G61MP can be installed as either a Non−Direct Vent or a Direct Vent gas central furnace. NOTE − In Non-Direct Vent installations, combustion air is taken from indoors and flue gases are discharged outdoors. In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged outdoors. Intake and exhaust pipe sizing in Direct Vent applications and exhaust pipe sizing in Non-Direct Vent applications −− Size pipe according to tables 12 and 13.
Use the following steps to correctly size vent pipe diameter. 1 − Determine the vent termination and its corresponding equivalent feet value according to table 11. B−PVC Joint Cementing Procedure All cementing of joints should be done according to the specifications outlined in ASTM D 2855. 2 − Determine the number of 90° elbows required for both indoor and outdoor (e.g. snow riser) use. Calculate the corresponding equivalent feet of vent pipe.
C− Venting Practices The thickness of construction through which vent pipes may be installed is 24" (610mm) maximum and 3" (76mm) minimum. If a G61MP furnace replaces a furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas appliance must be checked. Without the heat of the original furnace flue products, the existing vent pipe is probably oversized for the single water heater or other appliance.
TYPICAL EXHAUST PIPE CONNECTIONS HORIZONTAL DIRECT OR NON-DIRECT VENT APPLICATIONS (Horizontal Right-Hand Air Discharge Application Shown) *Limit pipe length to 2" in G61MPV−110 and −135 applications. 2−1/2", 3", OR 4" G61MP−36B−045 G61MP−36B−070 G61MP−48C−090 G61MP−60C−090 G61MP−48C−110* G61MP−60C−110* G61MP−60C−135* REDUCER 2"* 2" CAUTION Do not discharge exhaust into an existing stack or stack that also serves another gas appliance.
TYPICAL AIR INTAKE PIPE CONNECTIONS UPFLOW OR DOWNFLOW DIRECT VENT APPLICATIONS (Right-Hand Exit in Upflow Application Shown) 2−1/2", 3" OR 4 2−1/2", 3" OR 4 REDUCER 2 2 * 2 PLUG (Must be glued in place) 2 * 2 G61MP−36B−045 G61MP−36B−070 G61MP−48C−090 G61MP−60C−090 REDUCER 2 G61MP−36B−045 G61MP−36B−070 G61MP−48C−090 G61MP−60C−090 G61MP−48C−110* G61MP−60C−110* 2"* G61MP−36B−045 G61MP−36B−070 G61MP−48C−090 G61MP−60C−090 G61MP−48C−110* G61MP−60C−110* G61MP−60C−135* *Limit pipe length to 2" i
TYPICAL AIR INTAKE PIPE CONNECTIONS DOWNFLOW NON-DIRECT VENT APPLICATIONS (Right-Hand Exit in Downflow Applications Shown) 2" SWEEP ELL PLUG (Must be glued in place) INTAKE DEBRIS SCREEN (Provided) 6 in. Max. PLUG (Must be glued in place) 18 in. 2" SWEEP ELL INTAKE DEBRIS SCREEN (Provided) Downflow Evaporator Coil 2" Downflow Additive Flloor Base NOTE − Debris screen and sweep ell may be rotated, so that screen may be positioned to face forward, backward or to the side.
3 − To the extent that it is practical, close all building doors and windows and all doors between the space in which the appliances connected to the venting system are located and other spaces of the building. 4 − Close fireplace dampers. 5 − Turn on clothes dryers and any appliances not connected to the venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan.
VENT TERMINATION CLEARANCES FOR INSTALLATIONS IN THE USA AND CANADA* − G61MP VENT TERMINATION − AIR INLET OF OTHER APPLIANCE C less than 10 ft (3.048M) D F D E G A − Clearance above grade − 12 in. (305mm) minimum. B − Clearance to window or door that may be opened − for vent installations in USA − 12 in. (305mm) minimum. for vent installations in Canada − 12 in. (305mm) minimum for appliances 100,000 Btuh (30 kW); 36 in. (0.9m) minimum for appliances > 100,000 Btuh (30 kW).
Details of Intake and Exhaust Piping Terminations for Direct Vent Installations NOTE − In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged to outdoors. Intake and exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 20 through 28 show typical terminations. 1. Exhaust and intake exits must be in same pressure zone.
EXHAUST TERMINATION EXHAUST VENT 12" (305) ABOVE AVERAGE SNOW ACCUMULATION Inches (mm) Front View INTAKE VENT INTAKE TERMINATION FIELD−PROVIDED REDUCER MAY BE REQUIRED TO ADAPT LARGER VENT PIPE SIZE TO TERMINATION EXHAUST INTAKE DIRECT VENT CONCENTRIC ROOFTOP TERMINATION (71M80, 69M29 or 60L46) 1/2" (13) Foam Insulation in Unconditioned Space FIELD− PROVIDED REDUCER MAY BE REQUIRED TO ADAPT LARGER VENT PIPE SIZE TO TERMINATION FIGURE 25 EXHAUST TERMINATION INTAKE 12" (305) Min. above grade.
12" (305) MAX. for 2" (51) 20" (508) MAX. for 3" (76) (unless supported) Inches (mm) COVER EXHAUST VENT WITH 1/2" (13) FOAM INSULATION 12" (305) EXHAUST AIR 8" (203) Minimum INTAKE AIR INTAKE AIR 12" (305) Minimum ABOVE GRADE ÉÉÉÉÉÉÉÉÉÉ ÉÉÉÉÉÉÉÉÉÉ GRADE Side View EXHAUST AIR 12" MIN.
3. If exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, piping must be supported every 3 feet (.9m) as shown in figure 12. Refer to figure 31 for proper piping method. When exhaust piping must be run up an outside wall, any reduction in exhaust pipe size must be done after the final elbow. CONDENSATE TRAP LOCATIONS (Unit shown in upflow position) Horizontal left and optional downflow Horizontal right and optional downflow 12" (305) Max.
hose clamp. Condensate line must be sloped downward away from condensate trap to drain. If drain level is above condensate trap, condensate pump must be used. Condensate drain line should be routed within the conditioned space to avoid freezing of condensate and blockage of drain line. If this is not possible, a heat cable kit may be used on the condensate trap and line. Heating cable kit is available from Lennox in various lengths; 6 ft. (1.8m) − kit no. 18K48; 24 ft. (7.3m) − kit no. 18K49; and 50 ft.
III−START-UP A−Preliminary and Seasonal Checks 1 − Inspect electrical wiring, both field and factory installed for loose connections. Tighten as required. 2 − Check voltage at disconnect switch. Voltage must be within range listed on the nameplate. If not, consult the power company and have voltage condition corrected before starting unit. WARNING If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or death.
IV−HEATING SYSTEM SERVICE CHECKS A−C.S.A. Certification WHITE RODGERS 36E SERIES GAS VALVE HIGH FIRE MANIFOLD PRESSURE ADJUSTMENT ON SIDE (under cap) MANIFOLD PRESSURE TAP ON SIDE INLET PRESSURE TAP ON SIDE LOW FIRE MANIFOLD PRESSURE ADJUSTMENT ON SIDE (under cap) All units are C.S.A. (formally A.G.A. and C.G.A. combined) design certified without modifications. Refer to the G61MP Installation Instruction.
When checking piping connections for gas leaks, use preferred means. Kitchen detergents can cause harmful corrosion on various metals used in gas piping. Use of a specialty Gas Leak Detector is strongly recommended. It is available through Lennox under part number 31B2001. See Corp. 8411−L10, for further details. Do not use matches, candles, flame or any other source of ignition to check for gas leaks.
TABLE 17 High Heat CO2% For Nat Unit H− High Altitude G61MP−36B−045 6.5 − 7.5 7.4 − 8.4 G61MP−36B−070 6.5 − 7.5 7.4 − 8.4 G61MP−48C−090 6.9 − 7.9 7.8 − 8.8 G61MP−60C−090 6.9 − 7.9 7.8 − 8.8 G61MP−48C−110 7.2 − 8.2 8.1 − 9.1 G61MP−60C−110 7.2 − 8.2 8.1 − 9.1 G61MP−60D−135 7.4 − 8.4 8.3 − 9.3 TABLE 18 Low Heat CO2% For Nat Unit NOTE − In Canada, certification for installations at elevations over 4500 feet (1372 m) is the jurisdiction of local authorities.
J−Flame Signal A microamp DC meter is needed to check the flame signal on the ignition control. Flame (microamp) signal is an electrical current which passes from the furnace control through the sensor during unit operation. Current passes from the sensor through the flame to ground to complete a safety circuit.
D−Blower Speed Taps Filters Blower speed tap changes are made on the SureLight control board. See figure 4. The unused tap must be secured on dummy terminals "PARK " on the SureLight board. The high heating tap is connected to the "HI HEAT " terminal and the low heating / continuous blower tap is connected to the "LO HEAT" terminal. The cooling tap is connected to the COOL" tap. To change existing heat tap, turn off power then switch out speed tap on "HI HEAT" or LO HEAT" with tap connected to "PARK ".
G61MP−135 ONLY Remove and discard two shipping screws. FIGURE 41 9 − Remove 3/8 inch rubber cap from condensate drain plug and drain. Replace cap after draining. 10 − Disconnect condensate drain line from the condensate trap. Remove condensate trap (it may be necessary to cut drain pipe). Remove screws that secure condensate collars to either side of the furnace and remove collars. Remove drain tubes from cold end header collector box. 11 − Disconnect condensate drain tubing from flue collar.
Cleaning the Burner Assembly 1 − Turn off electrical and gas power supplies to furnace. Remove upper and lower furnace access panels. 2 − Mark all gas valve wires and disconnect them from the valve. 3 − Disconnect the gas supply line from the gas valve. Remove gas valve/manifold assembly. 4 − Mark and disconnect sensor wire from the sensor. Disconnect 2-pin plug from the ignitor at the burner box. 5 − Remove burner box cover and remove four screws which secure burner box assembly to vest panel.
VII− Wiring and Sequence of Operation Page 38
Sequence of Operation Sequence depends on type thermostat used. G61MP units are applicable for single stage or two stage thermostats. Both type thermostats are described below. Thermostat jumper E20 dictates which mode unit will operate in. See flow chart for more sequence detail. SureLight Control Self Check When there is a call for heat, the SureLight integrated control runs a self check. The control checks for S10 primary limit, S21 secondary limit (s) and S47 rollout switch normally closed contacts.
HEATING SEQUENCE OF OPERATION NORMAL AND ABNORMAL HEATING MODE POWER ON CONTROL SELF−CHECK OKAY? POLARITY OKAY? NO GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. CHECK FOR BROKEN IGNITOR OR OPEN IGNITER CIRCUIT. DS1 AND DS2 ALTERNATING FAST FLASH. GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. (RESET CONTROL BY TURNING MAIN POWER OFF.) DS1 ON, DS2 ON POLARITY REVERSED.
HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT DS1 AND DS2 SIMULTANEOUS FAST FLASH (Refer to box A on previous page) NO FIRST−STAGE (LOW FIRE) PRESSURE SWITCH CLOSED WITHIN 2.5 MINUTES? GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. UNIT WILL RETRY AFTER 5−MINUTE WAIT PERIOD. DS1 OFF, DS2 SLOW FLASH. YES 15−SECOND COMBUSTION AIR INDUCER PRE−PURGE INITIATED BY CLOSED FIRST−STAGE PRESSURE SWITCH (or 15 SECOND INTER−PURGE PERIOD.) DS1 AND DS2 SIMULTANEOUS FAST FLASH.
HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT. DS1 AND DS2 SIMULTANEOUS FAST FLASH. SEE BOX A. FLAME SIGNAL ABOVE (u0.22 microamps) NO LOW FLAME SIGNAL (Does not affect control operation) DS1 SLOW FLASH, DS2 FAST FLASH. YES YES SINGLE−STAGE THERMOSTAT MODE (E20 SET AT SINGLE") TWO STAGE THERMOSTAT MODE (E20 SET AT TWO") YES YES START SECOND−STAGE RECOGNITION ON DELAY (10 OR 15 MINUTES). DS1 AND DS2 SIMULTANEOUS FAST FLASH. 45−SECOND INDOOR BLOWER ON DELAY BEGINS.
HEATING SEQUENCE OF OPERATION CONTINUED SEE BOX A NORMAL OPERATION DS1 AND DS2 SIMULTANEOUS SLOW FLASH. SEE BOX B THERMOSTAT CALLS FOR HEAT DS 1 AND DS 2 SIMULTANEOUS FAST FLASH ARE PRIMARY, SECONDARY, ROLLOUT AND BACKUP SECONDARY LIMIT SWITCHES CLOSED? NO YES GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER ON. YES DS1 SLOW FLASH, DS2 ON. HAS PRIMARY, SECONDARY, ROLLOUT OR BACKUP SECONDARY LIMIT SWITCH CLOSED WITHIN 3 MINUTES? NO LIMIT SWITCH WATCHGUARD MODE. GAS VALVE OFF.
COOLING SEQUENCE OF OPERATION POWER ON YES IS POLARITY REVERSED? SIGNAL IMPROPER GROUND AT DS. SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED. SIGNAL POLARITY REVERSED. DS1 FAST FLASH, DS2 SLOW FLASH. NO NO YES IS THERE PROPER GROUND? IS VOLTAGE ABOVE 75 VOLTS? YES NO LOW VOLTAGE SIGNAL AT DS HOLDS UNTIL VOLTAGE RISES ABOVE 75 VOLTS. THERMOSTAT CALLS FOR FIRST−STAGE COOL. COMPRESSOR AND CONDENSER FAN ENERGIZED. INDOOR BLOWER ENERGIZED ON FIRST STAGE COOL SPEED AFTER 2 SECOND DELAY.
CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION MANUAL FAN SELECTION MADE AT THERMOSTAT. AFTER 2 SECOND DELAY, INDOOR BLOWER IS ENERGIZED ON CONTINUOUS FAN SPEED (LOW HEAT / LOW COOL). YES YES THERMOSTAT CALLS FOR FIRST STAGE COOL. THERMOSTAT CALLS FOR FIRST−STAGE HEAT. YES YES COMPRESSOR IS ENERGIZED AND INDOOR BLOWER CONTINUES TO OPERATE IN LOW COOL SPEED. YES BURNERS IGNITE AND INDOOR BLOWER CONTINUES TO OPERATE IN CONTINUOUS LOW (LOW HEAT / LOW COOL) MODE.
VIII− Field Wiring Applications and Jumper Settings Field Wiring Applications Thermostat 1 Heat / 1 Cool Jumper Settings (See figure 4) W915 E20 Y1 to Y2 SINGLE Leave Installed Wiring Connections S1 T’STAT CONTROL TERM. STRIP NOTE − Use dip switch 3 to set second−stage heat ON delay. ON−10 minutes. OFF−15 minutes. 1 Heat / 2 Cool HSXB15 (LSOM) SINGLE Clip S1 T’STAT CONTROL TERM. STRIP NOTE − Use dip switch 3 to set second−stage heat ON delay. ON−10 minutes. OFF−15 minutes.
Field Wiring Applications (Continued) Thermostat FM21 Heat Pump / 1 Cool Jumper Settings (See figure 4) W915 E20 Y1 to Y2 SINGLE Leave Installed Wiring Connections CONTROL TERM. STRIP FM21 *Disconnect existing furnace transformer and replace with 75VA, 24V transformer if defrost option to be used. 75VA, 24V TRANSFORMER* NOTE − Wiring connections to outdoor unit and thermostat made at FM21 control board per FM21 instructions. Page 47 NOTE − Cut Y1/Y2 jumper for two−stage cooling.
IX−SURELIGHT® CONTROL TROUBLESHOOTING CHART UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE Condition Possible Cause 1.1 1.1.1 − Both diagnostic lights fail to light up. Main voltage 120V not supplied to unit. LED#1−Off LED#2−Off ACTION 1 − Check for correct wiring of 120V to power make up box and transformer. ACTION 2 − Check 24V wiring to control board. 1.1.3 Blown fuse ACTION 1 − Replace fuse.
PROBLEM 1: UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE Condition Possible Cause Corrective Action / Comments 1.5 − Diagnostic lights flash the improper main g ground. 1.5.1 Improper ground to the unit. ACTION 1 − Check that the unit is properly ground. ACTION 2 − Install a proper main ground to the unit 1.5.2 6−Pin connector is improperly attached to the circuit board. ACTION 1 − Check 6−pin connector for proper installation. Correctly insert connector into control. 1.5.
PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER DOES NOT ENERGIZE (CONT.). Condition 2.3 − Unit operates with a cooling and continuous fan demand. − Combustion air inducer will not start with a Heating demand. − Diagnostic lights flash the pressure switch failure code 2.5 minutes after heating demand. LED#1−Off, LED#2−Slow Flash Possible Cause Corrective Action/Comments 2.3.1 Miswiring of furnace or improper connections to combustion air inducer.
PROBLEM 4: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER ENERGIZES, IGNITOR IS ENERGIZED. Condition Possible Cause Corrective Action/Comments 4.1 4.1.1 Check that gas is being supplied to the unit. ACTION 1 − Check line pressure at the gas valve. Pressure should not exceed 13" WC for both natural and propane. Line pressure should read a minimum 4.5" WC for natural and 8.0"WC for propane. 4.1.2 Miswiring of gas valve or looseconnections at multi−pin control amp plugs or valve.
PROBLEM 5: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN PREMATURELY (CONT.) Condition 5.3 − Combustion air inducer energizes with a heating demand. − Burners light. − Roll−out switch trips during the heating demand. − Diagnostic lights flash roll−out failure. LED#1−On LED#2−Slow Flash 5.4 − Combustion air inducer energizes with a heating demand. − Burners light roughly and the unit fails to stay lit. − Diagnostic lights flash watchguard flame failure.
PROBLEM 6: CONTROL SIGNALS LOW FLAME SENSE DURING HEATING MODE Condition Possible Cause Corrective Action/Comments 6.0 − Unit operates correctly but the diagnostic lights flash low flame sense code code. 6.1.1 Sensor rod is improperly located on the burner. ACTION 1 − Check the sensor rod for proper location on the burner. Properly locate the sensor rod or replace if rod cannot be located correctly. 6.1.2 Sensor rod is contaminated. ACTION 1 − Check sensor rod for contamination or coated surface.
SERVICE NOTES Page 54
