SERVICE MANUAL NF96DV Gas Furnace - Downflow This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to the potential for personal injury or death. Table of Contents WARNING Technical Specifications - NF96DV ......2 Parts Arrangement............5...
Technical Specifications - NF96DV MODEL NUMBER GUIDE N F F 96 96 D D V V 5 5 C C XX BRAND MAJOR/MINOR REVISION N - GE CABINET WIDTH PRODUCT B - 17.5” F - FURNACE, GAS C - 21” AFUE NOMINAL CFM 3 - 1200 CFM...
Unit Components WARNING NF96DV unit components are shown in Figure 1. The gas Shock hazard. valve, combustion air inducer and burners can be accessed Disconnect power before servicing. Integrated control by removing the access panel. Electrical components are is not field repairable. If control is inoperable, simply in the control box (Figure 2) found in the blower section.
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CFM LED Pin # Function An amber LED is provided on the control board to display Gas Valve Second Stage CFM. To determine what CFM the motor is delivering at any Second Stage Prove Switch time, count the number of times the amber LED flashes. Each flash signifies 100 CFM;...
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Heat Stage Jumper (single stage shown) Air Flow Heat Jumper Taps Cool Taps TERMINAL DESIGNATIONS HUM -Humidifier (120VAC) Line - Input (120VAC) XFMR - Transformer (120VAC) EAC - Indoor Air Accessory (120VAC) Cool - Cool Speed (120VAC) Park 1 - Dead terminal for alternate speed tap Park 2 - Dead terminal for alternate speed tap Figure 3.
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Indoor Blower Motor MOTOR CONTROLLER Figure 4. GenTeq Blower Motor B3 Power Choke Blower Motor (4 and 5 Ton Only) STATOR (B3) (WINDINGS) BEARING Figure 6. OUTPUT SHAFT ROTOR WARNING During blower operation, the ECM motor emits Figure 5. Blower Motor Components energy that may interfere with pacemaker operation.
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Initial Power Up POWER CONTROL When line voltage is applied to B3, there will be a large CONNECTOR J48 CONNECTOR J49 inrush of power lasting less than 1/4 second. This inrush PIN 1 C1 charges a bank of DC filter capacitors inside the controller. PIN 2 W / W1 PIN 3 C2 If the disconnect switch is bounced when the disconnect is...
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Motor speed is determined by the size of the electrical pulse sent to the motor windings. The longer the pulse, the faster the motor. OUTPUT FROM CONTROLLER TO MOTOR WINDINGS WINDINGS TURNED OFF WINDINGS TURNED ON ON PULSE OFF PULSE The frequency of the pulses to the windings is 20KHz.
Burners Heating Components All units use inshot burners. Burners are factory set and require no adjustment. Always operate the unit with the burner box front panel in place. Each burner uses an orifice Ignitor that is precisely matched to the burner input. Burners can The ignitor is made of durable silicon nitride.
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Burner Assembly Intake Air Top Cap Sensor Rollout Switch Rollout Switch Ignitor Manifold And Gas Orifices Burner Box Cover Two-Stage Gas Valve Figure 9. Heating Components Page 14 31-5000727 Rev. 0...
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Test 1 Check ignitor circuit for correct resistance. Remove 4-pin plug from control. Check ohms reading across terminals 1 and 5. Reading should be between 39 and 70 ohms. If value is correct, this is the only test needed. If the reading on the meter is not correct, (0 or infinity) then a second test is needed.
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Combustion Air Inducer Pressure Switch (S18) NF96DV series units are equipped with a dual combustion air pressure switch (first and second stage) located on the combustion air inducer orifice bracket. See Figure 11. The switch is connected to the combustion air inducer housing by means of a flexible silicone hose.
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Pressure Switch Check Operate unit and observe manometer reading. Readings will change as heat exchanger warms. To check pressure switch differential, refer to Figure 12 and use the provided fittings and tubing to follow the steps Take one reading immediately after start-up. below.
Canadian Applications Only - Pipe, fittings, primer and Placement and Installation solvent cement used to vent (exhaust) this appliance must be certified to ULC S636 and supplied by a single All pipe, fittings, primer and solvent cement must conform manufacturer as part of an approved vent (exhaust) with American National Standard Institute and the American system.
Removal of the Furnace from Common Vent After assembly, wipe excess cement from pipe at end of fitting socket. A properly made joint will show a bead around its entire perimeter. Any gaps may indicate an WARNING improper assembly due to insufficient solvent. CARBON MONOXIDE POISONING HAZARD Handle joints carefully until completely set.
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Exhaust Piping (Figure 15) Close all building doors and windows and all doors between the space in which the appliances remaining Route piping to outside of structure. Continue with connected to the common venting system are located installation following instructions given in piping termination and other spaces of the building.
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2” 2” Pipe size determined in 2” 2” Table 10A through 10C. 2” TRANSITION 3” *2” 3” *2” TRANSITION *2” INTAKE EXHAUST TOP VIEW * When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible. NOTE −...
INTAKE Roof Terminated SCREEN Exhaust Pipe (Provided) Inlet Air Minimum 12 in. (305mm) Ventilation Furnace above Crawl Louvers (Crawl Space) Space Floor Coupling or *Intake Debris Screen Provided 3 in. to 2 in. Transition (Field Provided) * See Maximum Vent Lengths table NOTE - Air intake screen and elbow may be rotated, so that screen may be positioned to face forward or to either side.
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Regardless of the diameter of pipe used, the standard roof Use the following steps to correctly size vent pipe diameter. and wall terminations described in section Exhaust Piping Terminations should be used. Exhaust vent termination pipe is sized to optimize the velocity of the exhaust gas as it exits the termination.
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Maximum Allowable Intake or Exhaust Vent Length in Feet Standard Termination at Elevation 0 - 4500 ft 1-1/2" Pipe 2" Pipe 2-1/2" Pipe 3" Pipe Number of 90° Model Model Model Model Elbows Used Standard Termination Elevation 4500 - 10,000 ft 1-1/2"...
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Maximum Allowable Intake or Exhaust Vent Length in Feet Concentric Termination at Elevation 0 - 4,500 ft 1-1/2" Pipe 2" Pipe 2-1/2" Pipe 3" Pipe Number of 90° Model Model Model Model Elbows Used Concentric Termination Elevation 4,501 - 10,000 ft 1-1/2"...
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Maximum Allowable Exhaust Vent Length Using Ventilated Attic or Crawl Space for Intake Air in Feet Standard Termination at Elevation 0 - 10,000 ft 1-1/2” Pipe 2” Pipe 2-1/2" Pipe 3" Pipe Number of 90° Capacity Capacity Capacity Capacity Elbows Used NOTE: Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
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Maximum Allowable Exhaust Vent Pipe Length (in ft.) without Insulation in Unconditioned Space for Winter Design Temperatures Unit Input Size Winter Design Vent Pipe Temperatures ºF (ºC) Diameter 1-1/2 in. 32 to 21 2 in. (0 to -6) 2-1/2 in. 3 in.
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VENT TERMINATION CLEARANCES FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA INSIDE CORNER DETAIL Fixed Operable Fixed Closed Closed Operable AREA WHERE TERMINAL AIR SUPPLY INLET VENT TERMINAL IS NOT PERMITTED US Installations Canadian Installations Clearance above grade, veranda, 12 inches (305mm) or 12 in.
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Details of Intake and Exhaust Piping Intake and exhaust pipes should be placed as close together as possible at termination end (refer to Terminations for Direct Vent Installations illustrations). Maximum separation is 3” (76MM) NOTE: In Direct Vent installations, combustion air is taken on roof terminations and 6”...
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On field-supplied terminations, a minimum distance STRAIGHT-CUT OR between the end of the exhaust pipe and the end of ANGLE-CUT IN DIRECTION OF ROOF SLOPE * the intake pipe without a termination elbow is 8” and a minimum distance of 6” with a termination elbow. See 3”...
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VENT TERMINATION CLEARANCES FOR NON-DIRECT VENT INSTALLATIONS IN THE US AND CANADA INSIDE CORNER DETAIL Fixed Operable Fixed Closed Closed Operable AREA WHERE TERMINAL AIR SUPPLY INLET VENT TERMINAL IS NOT PERMITTED US Installations Canadian Installations Clearance above grade, veranda, 12 inches (305mm) or 12 in.
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Details of Exhaust Piping Terminations for Non- STRAIGHT-CUT OR Direct Vent Applications * SIZE TERMINATION PIPE PER EXHAUST ANGLE-CUT IN DIRECTION PIPE TERMINATION SIZE REDUCTION TABLE OF ROOF SLOPE * 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 EXHAUST VENT Minimum 12”...
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FIELD FABRICATED WALL TERMINATION NOTE − FIELD−PROVIDED REDUCER MAY BE 2” (51mm) 3” (76mm) REQUIRED TO ADAPT LARGER VENT PIPE SIZE Vent Pipe Vent Pipe TO TERMINATION A− Minimum clearance above grade or average 12” (305 mm) 12” (305 mm) snow accumulation B−...
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For the Province of Ontario, Horizontal Sidewall Vent Applications Only For exterior horizontal venting applications, the 2” X 1.5” reducer for 2” venting at the point where the exhaust pipe exits the structure is not required in direct or nondirect vent applications in the Province of Ontario. In these applications, the vent should be oriented such that the exhaust plume is unobjectionable.
Use a large flat head screw driver or a 1/2” drive Condensate Piping socket extension and remove plug (Figure 35) from the cold end header box at the appropriate location This unit is designed for either right- or left-side exit of on the side of the unit.
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CAUTION Do not use copper tubing or existing copper condensate lines for drain line. If unit will be started immediately upon completion of installation, prime trap per procedure outlined in the Start-Up section. Condensate line must slope downward away from the trap to drain.
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Optional Condensate Drain Connection Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) 90° Street Elbow 3/4 inch PVC (not furnished) Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.
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Optional Condensate Drain Connection Adapter 1/2 inch slip X 1/2 inch mpt (Not Furnished) 90° Street Elbow 1/2 inch PVC (Not Furnished) Adapter 1/2 inch slip X 1/2 inch mpt (Not Furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.
Placing the Furnace into Operation Start-Up NF96DV units are equipped with an ignition system. Do NOT attempt to manually light burners on this furnace. Preliminary and Seasonal Checks Each time the thermostat calls for heat, the burners will Inspect electrical wiring, both field and factory installed automatically light The ignitor does not get hot when there for loose connections.
Gas Piping This furnace is equipped with an ignition device which automatically lights the burners. Do not try to light the burners by hand. CAUTION Remove the upper access panel. If a flexible gas connector is required or allowed by Move gas valve switch to OFF.
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When checking piping connections for gas leaks, use Shut unit off and remove manometer as soon as an preferred means. Kitchen detergents can cause harmful accurate reading has been obtained. corrosion on various metals used in gas piping. Use of a Start unit and perform leak check.
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Proper Combustion High Altitude Furnace should operate minimum 15 minutes with correct The manifold pressure, gas orifice and pressure switch manifold pressure and gas flow rate before checking may require adjustment or replacement to ensure proper combustion. Take combustion sample beyond the flue operation at higher altitudes.
Proper Ground and Voltage In addition, measure the AC voltage from Line Hot A poorly grounded furnace can contribute to premature to Line Neutral (spade terminals) on the integrated ignitor failure. Use the following procedure to check for control. See Figure 45. This voltage should be in the ground and voltage to the integrated control.
External Static Pressure Typical Operating Characteristics 1. Tap locations shown in Figure 47. Punch a 1/4” diameter hole in supply and return air Blower Operation and Adjustment plenums. Insert manometer hose flush with inside Blower operation is dependent on thermostat control edge of hole or insulation.
Maintenance Furnace Cabinet Width Minimum Filter Size 17-1/2” 16 x 25 x 1 (1) 21” WARNING Table 18. ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD. Exhaust and Air Intake Pipes Failure to follow safety warnings exactly could result in Check the exhaust and air intake pipes and all connections dangerous operation, serious injury, death or property for tightness and to make sure there is no blockage.
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Reinstall screens, reconnect hoses and turn on power Mark and remove wires from pressure switch assembly. to unit. Remove the assembly. Keep tubing attached to pressure switches. Disconnect the plug from the combustion air inducer. Remove two screws which secure combustion air inducer to collector box.
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Carefully connect combustion air pressure switch Mark and disconnect sensor wire from the sensor. tubing from pressure switches to proper ports on cold Disconnect wires from flame rollout switches. end header collector box. Disconnect combustion air intake pipe. It may be Reconnect condensate drain line to the cold end necessary to cut the existing pipe to remove burner header box.
Wiring and Sequence of Operation NOTES: PRESS AND RELEASE FAULT CODE HISTORY BUTTON TO DISPLAY FAULT CODES. TO ERASE CODES, PRESS AND HOLD BUTTON IN FOR MORE THAN 5 SECONDS IF ANY OF THE ORIGINAL WIRE AS SUPPLIED WITH THE FURNACE MUST BE REPLACED, IT MUST BE REPLACED WITH WIRING MATERIAL HAVING A TEMP.
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Sequence of Operation Cooling The unit is set up at the factory for single stage cooling. On a call for heat from the room thermostat, the control For two stage cooling operation, clip the jumper wire board performs a 1 second self check. Upon confirmation located between the Y to Y2 terminals on the integrated that the pressure switch contacts are in an open position, ignition/blower control board.
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All specifications and illustrations subject to change without notice and without incurring obligations. Printed in the U.S.A. Page 52 31-5000727 Rev. 0...