International comfort products N9MP1, N9MP2, H9MPD, C9MPD, T9MPD Service Manual

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MULTI POSITION

90% SINGLE STAGE

GAS FURNACES

Part Number 440 08 2011 00

N9MP1, N9MP2 & *9MPD

* Denotes brand H, C, T

Manufactured by:

This manual supports single stage “C” series and later condensing gas furnaces

2/2006

N9MP1 − Indoor combustion air (1 pipe only)

N9MP2 − Direct Vent ONLY (2 pipe only)

*9MPD − Dual Certified Venting (1 or 2 pipes)

* Denotes Brand (T, C or H)

Service Manual

Single Stage Multi Position Furnace

TABLE OF CONTENTS

1. INTRODUCTION 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. UNIT IDENTIFICATION 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. FURNACE THEORY OF OPERATION 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. ELECTRICAL SUPPLY 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5. INTERLOCK SWITCH 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6. GAS SUPPLY 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7. L.P. PRESSURE SWITCH 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8. HONEYWELL VR8205S GAS VALVE 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9. HIGH ALTITUDE OPERATION 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10. CHECKING TEMPERATURE RISE 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11. ROOM THERMOSTATS 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12. CONTROL WIRING 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13. TWINNING KITS 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14. LIMIT SWITCHES 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

15. PRESSURE SWITCHES 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16. HIGHER/LOWER NEGATIVE PRESSURES 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17. VENT/COMBUSTION AIR PIPING 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18. STANDARD VENT TERMINATION 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

19. CONCENTRIC VENT TERMINATION 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

20. COMBUSTION BLOWER 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21. CONDENSATE DRAIN TRAP 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

22. SEQUENCE OF OPERATION 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

23. CHECKING FLAME CURRENT 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24. CAPACITORS 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25. BLOWER ASSEMBLY 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

BLOWER PERFORMANCE DATA 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

WIRING DIAGRAM 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TECHNICAL SERVICE DATA (N9MP1 C1) 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TECHNICAL SERVICE DATA (N9MP2 C1) 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TECHNICAL SERVICE DATA (*9MPD C1) 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TROUBLE SHOOTING GUIDE 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIAGNOSTIC CODE SECTION 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TROUBLE SHOOTING CHART #1 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TROUBLE SHOOTING CHART #2 37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TROUBLE SHOOTING CHART #3 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INDEX

40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Manual

Single Stage Multi Position Furnace

INTRODUCTION

This service manual is designed to be used in conjunction with the installation manual and/or technical support manual provided with each furnace.

These furnaces represent the very latest in high efficiency gas furnace technology. Consequently, they incorporate the use of certain controls that contain highly sophisticated electronic components which are not user serviceable. Therefore, it is essential that only competent, qualified, service personnel attempt to install, service, or maintain this product.

This Service manual was written to assist the professional

This service manual covers the following models; *9MPD− − − − − − C or later, *9MP1 − − − − − − C or later and *9MP2 − − − − − − C or later models. The overall operation of all of these models is essentially the same.

This manual, therefore, will deal with all subjects in a general nature (I.E. all text will pertain to all models) unless that subject is unique to a particular model or family, in which case it will be so indicated.

It will be necessary then for you to accurately identify the unit you are servicing, so you may be certain of a proper

diagnosis and repair. (See Unit Identification, Page 3) HVAC service technician to quickly and accurately diagnose and repair any malfunction of this product.

SAFETY REQUIREMENTS

Recognize safety information. This is the safety−alert symbol . When you see this symbol on the furnace and in instructions manuals be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, or CAUTION. These words are used with the safety−alert symbol. DANGER identifies the most serious hazards, those that will result in severe personal injury or death. WARNING signifies a hazard that could result in personal injury or death. CAUTION is used to identify unsafe practices that could result in minor personal injury or product and property damage. NOTE is used to highlight suggestions that will result in enhanced installation, reliability, or operation.

Installing and servicing heating equipment can be hazardous due to gas and electrical components. Only trained and qualified personnel should install, repair, or service heating equipment.

Untrained service personnel can perform basic maintenance functions such as cleaning and replacing air filters. All other operations must be performed by trained service personnel. When working on heating equipment, observe precautions in the literature, on tags, and on labels attached to or shipped with the unit and other safety precautions that may apply.

Follow all safety codes. In the United States, follow all safety codes including the current edition National Fuel Gas Code (NFGC) ANSI Z223.1−2002/NFPA No. 54−2002. In Canada, refer to the current edition of the National Standard of Canada Natural Gas and Propane Installation Code (NSCNGPIC) CSA B149.1−05. Wear safety glasses and work gloves. Have fire extinguisher available during start−up and adjustment proce- dures and service calls.

These instructions cover minimum requirements and conform to existing national standards and safety codes. In some instances, these instructions exceed certain local codes and ordinances, especially those that may not have kept up with changing residential construction practices. We require these instructions as a minimum for a safe installation.

International Comfort Products LLC

Lewisburg, TN 37091

440 08 2011 00

Single Stage Multi Position Furnace

UNIT IDENTIFICATION

Service Manual

The unit’s rating plate contains important information for the service technician. It also lists the complete Model Manufacturing and Serial Numbers.

placement parts (example, in certain model families a unit

having a MARKETING REVISION of “C” is likely to be

equipped with one or more different components. These complete numbers are required to obtain correct re-

MODEL NUMBER IDENTIFICATION GUIDE

* 9 M P D 0 75 B 1 2 C 1

Brand Identifier Engineering Rev.

T = Tempstar Denotes major changes

C = Comfortmaker Marketing Digit

H = Heil Denotes major change

A = Arcoaire

N = Non−Brand Specific (Generic) Cooling Airflow

Brand Identifier 08 = 800 CFM

8 = Non−Condensing, 80+% Gas Furnace 12 = 1200 CFM

9 = Condensing, 90+% Gas Furnace 14 = 1400 CFM

Installation Configuration 16 = 1600 CFM

UP = Upflow DN = Downflow UH = Upflow/Horizontal 20 = 2000 CFM

HZ = Horizontal DH = Downflow/Horizontal

MP = Multiposition, Upflow/Downflow/Horizontal Cabinet Width

Major Design Feature B = 15.5″ Wide

1 = One (Single) Pipe N = Single Stage F = 19.1″ Wide

2 = Two Pipe P = PVC Vent J = 22.8″ Wide

D = 1 or 2 Pipe T = Two Stage L = 24.5″ Wide

L = Low NOx V = Variable Speed Input (Nominal MBTUH)

FURNACE THEORY OF OPERATION

The high efficiencies and lower profile (compared to past series) of this furnace have been obtained using design techniques not typical of traditional furnace designs. A brief description of these new design techniques and the purpose they serve follows.

1. Reducing the height of the furnace while maintaining the high efficiency of pervious models required maintaining the surface area of the heat exchanger and yet minimizing the overall size.

The design required to achieve these results is the “SERPENTINE” design, wherein the flue gasses must follow a serpent shaped passage through the heat exchanger via convection.

This “Serpentine” path is resistive to normal convective flow, and requires that a partial vacuum be created at the outlet of the heat exchanger to maintain the flow of flue products through the heat exchanger.

2. The serpentine heat exchanger design does not lend itself well to the ribbon type, or slotted port type burner found in more traditional design furnaces for the following reasons:

A. The secondary combustion airflows at right angles

to the burner flame, making it likely to “pull” the flame off a ribbon or slotted port type burner.

B. The flame “height” of a ribbon or slotted port type

burner would make it difficult (if not impossible) to prevent impingement of the flame on the heat exchanger surfaces whole maintaining the low profile heat exchanger.

For these reasons, an “INSHOT” type burner is used in this series. The inshot burner (also called a “jet” burner) fires a flame straight out its end. This burner is designed to fire into a tube style heat exchanger, making it an ideal application in the tube−like passages of the serpentine heat exchanger.

3. In order to extract the maximum amount of heat possible from the flue gasses, a secondary heat exchanger (condenser) is connected to the outlet of the primary heat exchanger. This condenser removes additional heat from the flue gasses, causing their temperature to drop below dew point. This results in the forming of condensation (water) which then must be routed to a drain.

4. The placement of the secondary heat exchanger at the outlet of the primary heat exchanger creates additional resistance to the flow of gasses.

5. To overcome the resistance to convective flow of the Primary and Secondary heat exchangers requires the use of an Induced Draft Combustion Blower Assembly.

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Service Manual

Single Stage Multi Position Furnace

6. The Combustion Blower Assembly is mounted on the outlet side of the Secondary heat exchanger, This blower creates a partial vacuum (negative pressure) within the heat exchangers drawing the flue products out of the furnace.

7. A pressure switch (Air Proving Switch) is used as a safety device that prevents the ignition system from

ELECTRICAL SUPPLY

ELECTRICAL SHOCK HAZARD.

Failure to turn off power could result in death or personal injury.

Turn OFF electrical power at fuse box or service panel before making any electrical connections and ensure a proper ground connection is made before connecting line voltage.

SUPPLY CIRCUIT

The furnace cannot be expected to operate correctly unless it is properly connected (wired) to an adequately sized single branch circuit. Line voltage wires should conform to temperature limitation of 63° F (35° C) rise and be sized for the unit maximum amps stated on the rating plate. Add the full load amps for potential field − installed accessories that would receive power from the furnace control. Consult NEC or local codes for proper wire and circuit sizing.

WARNING

firing the furnace until it senses that a proper draft has been established through the furnace.

SEQUENCE OF OPERATION − HEATING

Refer to the ignition control section for sequence of operation.

Figure 1

NOTE: Junction Box can be mounted to either the left or right side.

115V. 60 Hz

HOT

NEUT.

Connection

Box

Ground

Low Voltage Terminal Board

Electrical Connections

W BK

Models may have 1 or 2 pressure switches

SUPPLY VOLTAGE

Supply voltage to the furnace should be a nominal 115 volts. It MUST be between 104 volts and 127 volts. Supply voltage to the furnace should be checked WITH THE FURNACE IN OPERATION. Voltage readings outside the specified range can be expected to cause operating problems. Their cause MUST be investigated and corrected.

ELECTRICAL GROUND

Proper grounding of the electrical supply to THE FURNACE IS REQUIRED for safety and operational reasons.

POLARITY

CORRECT POLARITY of the line voltage supply to the furnace is also required for safety and operational reasons. The furnace control MUST have proper line voltage polarity to operate properly.

25−24−90−2

NOTE: 115 VAC/60Hz/single−phase Operating voltage range*: 127 VAC max, 104 VAC min.

* Permissible limits of voltage at which unit will operate satisfactorily

CHECKING GROUNDING AND POLARITY

Grounding may be verified as follows:

1. Turn the power supply “OFF”.

2. Using an Ohmmeter check for continuity between the Neutral (white) wire and Ground wire (green) of the supply circuit.

3. With the Ohmmeter set on the R x 1 scale, the read- ing should be zero Ohms.

4. A zero Ohm reading indicates that the neutral is grounded back to the main panel.

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Single Stage Multi Position Furnace

Service Manual

5. An alternate check would be to check for continuity from the Neutral to a cold water pipe, (Pipe must be metal, and must have a continuous, uninterrupted connection to ground) or to a continuous, uninterrupted connection to ground) or to a driven ground rod.

6. Any readings other than zero Ohms would indicate a poor ground, or no ground.

Polarity may be verified as follows:

1. Turn the power supply “ON”.

2. Using a Voltmeter check for voltage between the Hot (Black) and Neutral (White) wire of supply circuit.

3. Reading should be Line (Supply) Voltage.

INTERLOCK SWITCH

The blower compartment door of all models is equipped with an interlock switch. (See Figure 2) This switch is “Normally Open” (closes when the door is on the furnace) and interrupts furnace operation when the door is open. This interlock switch is a safety device, and SHOULD NEVER BE BY−PASSED.

Since this is a single pole switch, (breaking only one side of the line) proper line polarity is essential to insure that furnace components are not “HOT” when switch is open. (See Checking Grounding and Polarity)

4. Check for Voltage between the Neutral (White) wire and Ground wire of the supply circuit.

5. Reading should be zero Volts. (if line voltage is read, polarity is reversed)

6. A zero Volt reading indicates there is no voltage potential on Neutral wire.

7. Double check by checking for voltage between the Hot (Black) wire and Ground wire of the supply circuit.

8. Reading should be Line (supply) Voltage. (if zero volts is read, there is no ground, or polarity is reversed.)

Figure 2

Typical Interlock Switch

GAS SUPPLY

An adequately sized gas supply to the furnace is required for proper operation. Gas piping which is undersized will not provide sufficient capacity for proper operation. Piping should be sized in accordance with accepted industry standards. Refer to NFGC and ANSI Z223.1 for proper gas pipe size.

NATURAL GAS

Inlet (Supply) pressure to the furnace should be checked (at the gas valve) with ALL OTHER GAS FIRED APPLIANCES OPERATING. Inlet (Supply) pressure to the furnace under these conditions MUST be within minimum and maximum values listed on rating plate. If the inlet pressure is less, it may be an indication of undersized piping or regulator problems.

10−12−96

L.P. GAS

Inlet (Supply) pressure to the furnace should be checked in the same manner as for Natural Gas, however with L.P. Gas, the inlet pressure MUST be a minimum of 11″ W.C. If this cannot be obtained, problems are indicated in either the regulator or pipe sizing.

CHECKING INPUT (FIRING) RATE

Once it has been determined that the gas supply is correct to the furnace, it is necessary to check the input (firing) rate. This can be done in two (2) ways. First by checking and adjusting (as necessary) the manifold (Outlet) pressure. The second way is to “Clock” the gas meter.

FIRE OR EXPLOSION HAZARD.

Turn OFF gas at shut off before connecting manometer.

Failure to turn OFF gas at shut off before connecting manometer can result in death, personal injury and/or property damage.

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Service Manual

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Figure 3

Pressure Connections

Typical U" Tube

Manometer

Gas Pressure Testing Devices

INCHES OF WATER

510

MAGNEHELIC

MAX. PRESSURE 15 PSIG

CHECKING MANIFOLD PRESSURE

NOTE: Make adjustment to manifold pressure with burners operating.

1. Remove the burner compartment door.

2. With gas OFF, connect manometer to outlet tapped opening on gas valve. Use manometer with a 0 to 15″ water column range.

3. Turn gas on. Remove the blower compartment door. Operate the furnace by jumpering R to W on the furnace control board.

4. Remove manifold pressure adjustment screw cover on furnace gas control valve. Turn adjusting screw counterclockwise to decrease manifold pressure and clockwise to increase pressure.

NOTE: Adjustment screw cover MUST be replaced on gas control valve before reading manifold pressure and operating furnace.

5. Obtain gas heating value and installation site altitude.

6. Set manifold pressure to value shown in Table 2, Table 3, Table 4 or Table 5.

7. When the manifold pressure is properly set, replace the adjustment screw cover on the gas control valve.

8. Remove jumper wire from thermostat connection on furnace control board. Remove manometer connection from manifold pressure tap, and replace plug in valve.

9. Check for leaks at plug.

10. Replace the burner compartment and blower compartment door.

Natural Gas Input Rating Check

NOTE: The gas meter can be used to measure input to furnace. Rating is based on a natural gas BTU content of 1,000 BTU’s per cubic foot. Check with gas supplier for actual BTU content.

1. Make sure burner compartment door is in place before performing the following steps.

2. Turn OFF gas supply to all appliances and start fur- nace.

Example

Natural Gas

BTU Content

1,000 3,600 48 75,000

No. of Seconds

Per Hour

1,000 x 3,600 ÷ 48 = 75,000 BTUH

Time Per Cubic

Foot in Seconds

BTU Per

Hour

3. Time how many seconds it takes the smallest (normally 1 cfh) dial on the gas meter to make one complete revolution. Refer to Example.

4. Relight all appliances and ensure all pilots are operating.

NOTE: If meter uses a 2 cubic foot dial, divide results (seconds) by two.

Alternate BTUH Input Ratings (USA Only)

Figure 4

Manifold Regulator Adjustment Under Cap

INLET

Inlet Pressure Tap 1/8 NPT

Typical Gas Control Valve Honeywell

HONEYWELL

OFF

25−24−98a

Outlet Pressure Tap

/8 NPT

OUTLET

The input rating of these furnaces can be changed from the standard input rating to the alternate input rating shown in Table 1, by changing the main burner orifices. Changing of burner orifices MUST be done by a qualified service technician. See section on changing orifices on page 9.

Table 1 Alternate Input Ratings, USA ONLY.

BTUH

Standard

Rating

50,000 40,000 #44 #55

75,000 60,000 #44 #55

100,000 80,000 #44 #55

125,000

BTUH

Alternate

Rating

100,000 #44 #55

Natural

Gas

Orifice*

Gas

Orifice**

* See Table 4 for High Altitude. ** See Table 5 for High Altitude

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Single Stage Multi Position Furnace

MANIFOLD PRESSURE AND ORIFICE SIZE FOR HIGH ALTITUDE APPLICATIONS

Service Manual

Table 2

HEATING

VALUE

at ALTITUDE

BTU/CU. FT.

700 −− −− −− −− −− −− −− −− −− −− −− −− 41 3.7

725 −− −− −− −− −− −− −− −− −− −− 41 3.7 41 3.4

750 −− −− −− −− −− −− −− −− −− −− 41 3.5 42 3.6

775 −− −− −− −− −− −− −− −− 41 3.6 42 3.6 42 3.3

800 −− −− −− −− −− −− 41 3.6 42 3.7 42 3.4 42 3.1

825 −− −− −− −− 41 3.7 41 3.4 42 3.5 42 3.2 42 2.9

850 −− −− −− −− 41 3.5 42 3.6 42 3.3 42 3.0 42 2.8

875 −− −− 41 3.6 42 3.6 42 3.4 42 3.1 42 2.8 42 2.6

900 −− −− 42 3.7 42 3.4 42 3.2 42 2.9 42 2.7 42 2.5

925 41 3.7 42 3.5 42 3.3 42 3.0 42 2.8 42 2.5 44 3.3

950 41 3.5 42 3.3 42 3.1 42 2.9 42 2.6 42 2.4 44 3.1

975 42 3.7 42 3.2 42 2.9 42 2.7 42 2.5 44 3.2 45 3.6

1000 42 3.5 42 3.0 42 2.8 42 2.6 42 2.4 45 3.7 45 3.4

1050 42 3.2 42 2.7 42 2.5 44 3.3 45 3.6 −− −− −− −− 1100 43 3.6 42 2.5 44 3.2 45 3.6 −− −− −− −− −− −−

NATURAL GAS MANIFOLD PRESSURE ( w.c.)

MEAN ELEVATION FEET ABOVE SEA LEVEL

Orifice

No.

0 to

2000

Manifold

Pressure

Orifice

No.

2001 to

3000

Manifold

Pressure

Orifice

No.

3001 to

4000

Manifold

Pressure

4001 to

5000

Orifice

No.

Manifold

Pressure

Orifice

No.

5001 to

6000

Manifold

Pressure

Orifice

No.

6001 to

7000

Manifold

Pressure

Orifice

No.

7001 to

8000

Manifold Pressure

NOTE: Natural gas data is based on 0.60 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI Z223.1−2002/NFPA 54−2002 or National Standard of Canada, Natural Gas And Propane Installation Code CSA B149.1−05.

Bold indicated the factory shipped orifice size #42.

Table 3

HEATING VALUE

at ALTITUDE

BTU/CU. FT.

2500 10.0 10.0 10.0 10.0 9.4 8.5 10.0

Orifice Size #55 #55 #55 #55 #55 #55 #56

NOTE: Propane data is based on 1.53 specific gravity. For fuels with different specific gravity consult the National Fuel Gas Code ANSI Z223.1−2002/NFPA 54−2002 or National Standard Of Canada, Natural Gas And Propane Installation Code CSA B149.1−05.

LPG or PROPANE GAS MANIFOLD PRESSURE ( w.c.) FOR THE 90% 80,000 BTUH MODEL AND ALTERNATE INPUT RATINGS

MEAN ELEVATION FEET ABOVE SEA LEVEL

0 to

2000

2001 to

3000

3001 to

4000

4001 to

5000

5001 to

6000

6001 to

7000

7001 to

8000

NOTE: The derating of these furnaces at 2% (Natural Gas) and 4% (Propane Gas) has been tested and design−certified by

CSA. In Canada, the input rating must be derated 5% (Natural Gas) and 10% (Propane Gas) for altitudes of 2,000 to 4,500 above sea level. Use the 2001 to 3000 column in Table 2, Table 3, Table 4 and Table 5.

The burner orifice part nos. are as follows: Orifice #41 1096942 Orifice #42 1011351 Orifice #43 1011377 Orifice #44 1011352

Orifice #47 1011378 Orifice #48 1113201 Orifice #49 1113202 Orifice #54 1011376 Orifice #55 1011354 Orifice #56 1011355

Orifice #45 1011353 Orifice #46 1011744

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Single Stage Multi Position Furnace

Table 4

HEATING

VALUE

at ALTITUDE

BTU/CU. FT.

700 −− −− −− −− −− −− −− −− −− −− −− −− −− −−

725 −− −− −− −− −− −− −− −− −− −− −− −− −− −−

750 −− −− −− −− −− −− −− −− −− −− 41 3.6 41 3.6

775 −− −− −− −− −− −− −− −− 41 3.4 41 3.4 41 3.4

800 −− −− −− −− −− −− 42 3.5 42 3.5 42 3.5 42 3.5

825 −− −− −− −− 42 3.3 42 3.3 42 3.3 42 3.3 42 3.3

850 −− −− −− −− 42 3.1 42 3.1 42 3.1 42 3.1 42 3.1

875 −− −− 43 3.5 43 3.6 43 3.6 43 3.6 43 3.6 43 3.6

900 −− −− 43 3.3 43 3.4 43 3.4 43 3.4 43 3.4 43 3.4

925 44 3.7 44 3.7 44 3.7 44 3.7 44 3.7 44 3.7 44 3.7

950 44 3.5 44 3.5 44 3.5 44 3.5 44 3.5 44 3.5 44 3.5

975 44 3.3 44 3.3 44 3.3 44 3.3 44 3.3 44 3.3 44 3.3

1000 44 3.2 44 3.2 44 3.2 44 3.2 44 3.2 44 3.2 44 3.2

1050 46 3.6 46 3.6 46 3.6 46 3.6 46 3.6 −− −− −− −−

1100 46 3.3 46 3.3 46 3.3 46 3.3 −− −− −− −− −− −−

NATURAL GAS MANIFOLD PRESSURE ( w.c.) FOR THE90% 80,000 BTUH MODEL AND ALTERNATE INPUT MODELS

MEAN ELEVATION FEET ABOVE SEA LEVEL

Orifice

No.

0 to

2000

Manifold

Pressure

Orifice

No.

2001 to

3000

Manifold

Pressure

Orifice

No.

3001 to

4000

Manifold

Pressure

Orifice

No.

4001 to

5000

Manifold

Pressure

Orifice

No.

5001 to

6000

Manifold

Pressure

Orifice

No.

6001 to

7000

Manifold

Pressure

Orifice

No.

7001 to

8000

Manifold Pressure

Bold indicated the factory shipped orifice size #44.

Table 5

HEATING VALUE

at ALTITUDE

BTU/CU. FT.

2500 10.0 10.0 9.0 10.0 9.4 8.5 10.0

Orifice Size #54 #54 #54 #55 #55 #55 #56

LPG or PROPANE GAS MANIFOLD PRESSURE ( w.c.) FOR THE 80,000 BTUH MODEL AND ALTERNATE INPUT MODELS

MEAN ELEVATION FEET ABOVE SEA LEVEL

0 to

2000

2001 to

3000

3001 to

4000

4001 to

5000

5001 to

6000

6001 to

7000

7001 to

8000

NOTE: The derating of these furnaces at 2% (Natural Gas) and 4% (Propane Gas) has been tested and design−certified by CSA. In Canada, the input rating must be derated 5% (Natural Gas) and 10% (Propane Gas) for altitudes of 2,000 to 4,500 above sea level. Use the 2001 to 3000 column in Table 2, Table 3, Table 4 and Table 5.

General Derating Rules

as per Table 3. Orifices can be ordered through your distributor. (See Figure 6)

1. These furnaces may be used at full input rating when installed at altitudes up to 2,000′. When installed above 2,000′, the input must be decreased 2% (natural) or 4% (LP) for each 1000′ above sea level in the USA. In Canada, the input rating must be derated 5% (natural) or 10% (LP) for each 1000′ above sea level. See Table 4 or Table 5 for required high altitude in- put rate.

2. For operation with natural gas at altitudes above 2,000′, orifice change and/or manifold pressure adjustments may be required for the gas supplied. First consult your local gas supplier, then refer to Table 2 for required pressure change and/or orifice change for high altitudes.

3. For operation with LP gas, gas orifices MUST be changed and manifold pressure MUST be maintained

Nameplate Sea Level Input Rate x (Multiplier)

Elevation

0′ - 2000′ 1.00 1.00 0.80

2001′ - 3000′ 0.90 1.00 0.80

3001′ - 4000′ 0.86 1.00 0.80

4001′ - 5000′ 0.82 1.00 0.80

5001′ - 6000′ 0.78 0.96 0.76

6001′ - 7000′ 0.74 0.92 0.72

7001′ - 8000′ 0.70 0.88 0.68

* Based on mid−range of elevation.

*High Altitude Input Rate =

High Altitude

Multiplier

LP Gas*

Standard Input

High Altitude

Multiplier LP Gas*

80,000 BTUH Input

Model

High Altitude

Multiplier LP Gas*

Alternate Input

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Single Stage Multi Position Furnace

Service Manual

Nameplate Sea Level Input Rate x (Multiplier)

Elevation

0′ - 2000′ 1.00 1.00 0.80

2001′ - 3000′ 0.95 1.00 0.80

3001′ - 4000′ 0.93 1.00 0.80

4001′ - 5000′ 0.91 1.00 0.80

5001′ - 6000′ 0.89 1.00 0.80

6001′ - 7000′ 0.87 1.00 0.80

7001′ - 8000′ 0.85 1.00 0.80

* Based on mid−range of elevation.

*High Altitude Input Rate =

High Altitude

Multiplier

Natural Gas*

Standard Input

High Altitude

Multiplier

Natural Gas*

80,000 BTUH Input

Model

High Altitude

Multiplier

Natural Gas*

Alternate Input

4. In cases where Table 2 or Table 3 is not applicable, eg. alternate input rate application, refer to Table 4 or Table 5 for required high altitude input rate.

Main Burner Flame Check

Allow the furnace to run approximately 10 minutes. Then inspect the main burner flames. See Figure 5.

Check for the following:

• Stable and blue flames. Dust may cause orange tips or wisps of yellow, but flames MUST NOT have solid, yellow tips.

• Flames extending directly from burner into heat exchanger.

• Flames do NOT touch sides of heat exchanger

NOTE: Main burner orifices can be changed for high alti-

tudes.

1. Disconnect gas line from gas valve.

2. Remove manifold from furnace.

3. Remove the orifices from the manifold and replace them with properly sized orifices.

4. Tighten the orifices so they are seated and gas tight approximately 11/8″ from the face of the orifice to the back of the manifold pipe. (See Figure 6) Make sure orifice is installed straight so that it forms a right angle (90°) to the manifold.

5. Reinstall manifold. Ensure burners do NOT bind on new orifices.

Figure 6

Changing Orifices

Measure from face of orifice to the back side of the manifold.

11/8″ to 13/16″

NOTE: For Ignitor location see Figure 7.

If any problems with main burner flames are noted, it may be necessary to adjust gas pressures or check for drafts.

Figure 5

Main Burner

Burner Face

10−10−78

Changing Orifices for High Altitude

ELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD

Failure to properly install orifices could result in death, personal injury and/or property damage.

Turn OFF electric power (at disconnect) and gas supply (at manual valve in gas line) when installing orifices. Installation of orifices requires a qualified service technician.

WARNING

Figure 7

NOTE: Flame sensor has a different orientation for all 050 models and alternate 040 input.

Ignitor Location

all dimensions are in inches.

High Altitude Installation

Gas input rate on the furnace rating plate is for installation at up to 2000′. The #54 burner orifices supplied in this kit are sized for Propane Gas at full rate ONLY, for use between 0−2000′ elevation. Do not use them above 2000′(except when noted by Table 3 or Table 5). Orifices for conversion at high altitude and alternate input must be ordered from Service Parts.

Standard Input:

Units may be installed at full input rating (25,000 BTUH per heat exchanger) when installed at altitudes up to 2000′.

80,000 BTUH model and Alternate Input (Conversions): See unit instructions to determine if model may be converted to alternate input.

Units may be installed at full input rating (20,000 BTUH per heat exchanger) when installed at altitudes up to 5000′.

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Single Stage Multi Position Furnace

In the USA, for furnaces fired on standard rate, the input rating for altitudes above 2000′ (5,000 for 80,000 BTUH and alternate in-

put) must be derated by 4% for each 1000′ above sea level (see Table 3 and Table 5)

In Canada, the input rating for altitudes above 2000′ (5,000 for 80,000 BTUH) must be reduced by 10% for altitudes of 2000′ to

4500′ above sea level. Use the 2001 to 3000 column in Table 3 and Table 5.

Alternate BTUH Input Ratings (USA Only)

The input rating of these furnaces can be changed from the standard input rating to the alternate input rating shown in Table 6, by

Table 6 Alternate Input Ratings, USA ONLY.

BTUH

Standard

Rating

50,000 40,000 #55

75,000 60,000 #55

100,000 80,000 #55

125,000

* See Table 5 for High Altitude

changing the main burner orifices. Changing of burner orifices MUST be done by a qualified service technician. See section on changing orifices.

CAUTION: See unit instructions to determine if model may be

converted to alternate input.

MANIFOLD PRESSURE AND ORIFICE SIZE FOR HIGH ALTITUDE APPLICATIONS

Table 7

HEATING VALUE

at ALTITUDE

BTU/CU. FT.

2500 10.0 10.0 9.0 10.0 9.4 8.5 10.0

Orifice Size #54 #54 #54 #55 #55 #55 #56

LPG or PROPANE GAS MANIFOLD PRESSURE ( w.c.) EXCEPT FOR THE 90% 80,000 BTUH MODEL AND ALTERNATE INPUT RATINGS

MEAN ELEVATION FEET ABOVE SEA LEVEL

0 to

2000

2001 to

3000

3001 to

4000

4001 to

5000

5001 to

6000

BTUH

Alternate

Rating

100,000 #55

6001 to

7000

Gas

Orifice*

7001 to

8000

Table 8

HEATING VALUE

at ALTITUDE

BTU/CU. FT.

2500 10.0 10.0 10.0 10.0 9.4 8.5 10.0

Orifice Size #55 #55 #55 #55 #55 #55 #56

LPG or PROPANE GAS MANIFOLD PRESSURE ( w.c.) FOR THE 90% 80,000 BTUH MODEL AND ALTERNATE INPUT RATINGS

MEAN ELEVATION FEET ABOVE SEA LEVEL

0 to

2000

2001 to

3000

3001 to

4000

4001 to

5000

5001 to

6000

6001 to

7000

7001 to

8000

NOTE: In the USA, for furnaces fired on standard rate, the input rating for altitudes above 2000′ (5,000 for 80,000 BTUH and alternate input) must be derated by 4% for each 1000′ above sea level (see Table 3 and Table 5)

In Canada, the input rating for altitudes above 2000′ (5,000 for 80,000 BTUH) must be reduced by 10% for altitudes of 2000′ to 4500′ above sea level. Use the 2001 to 3000 column in Table 3 and Table 5.

L.P. PRESSURE SWITCH

Models equipped for or converted to operate on LP Gas will be equipped with an LP Pressure Switch. If so equipped, the switch will be located in the gas supply line (in a “Tee” fitting), just ahead of the gas valve.

The purpose of this switch is to prevent furnace operating under low line (Supply) pressure conditions. Operating under low line pressure conditions, can create problems such as incomplete combustion, flashback, sooting, etc.

The switch is a “Normally Open” pressure operated switch that is wired in series with the furnace (air proving) pressure switch. The L.P. Pressure Switch closes when line (Supply) pressure is 8.0″ W.C. or higher. the L.P. Pressure Switch

Opens if line pressure falls below 6.0″+ 0.6″ W.C. interrupting power to the gas valve.

Figure 8

Typical L.P. Pressure Switch

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Single Stage Multi Position Furnace

HONEYWELL VR8205S Gas Valve

Service Manual

The VR8205S Gas Valve is a REDUNDANT type valve. This means that it consists of two (2) valves (internally) with independent operators (solenoids) that both must be energized before gas can flow through the valve. This redundancy provides an added safety measure. In case one of the valves sticks open (Mechanically), the second operator will close preventing the flow of gas.

If the valve does not open, check for 24 Volts across the two

HIGH ALTITUDE OPERATION

These furnaces are designed to operate in the majority of the country without modifications. At altitudes over 2,000′ above sea level, however, certain measures need to be taken to insure continued, safe reliable operation. For example, units must be de−rated for altitude (by adjusting manifold pressure and/or changing orifice size) based upon the type of fuel (I.E. Natural Gas or L.P. gas), Btu content of the gas, and installed altitude.

Altitudes over 4,000′ may require a different air proving pressure switch than the one installed at the factory. Check

CHECKING TEMPERATURE RISE

Figure 9

Thermometer:

Return Air Temp.

Return

Checking Temperature Rise

Supply

Air Flow

Thermometer;

Supply Air Temp.

wires to the valve during a call for heat. This check MUST be made IMMEDIATELY following the igniter warm−up peri- od (17 seconds). 24 Volts will be present ONLY for a period of 7 seconds after the igniter warm−up if flame is not proven.

If 24 Volts is present during the above check and the valve will NOT open, then replace the valve. If 24 Volts IS NOT present, problems are indicated in the control and/or wiring to the gas valve.

parts list for pressure switch and consult your distributor for part number and availability. In Canada, provincial codes may govern installation or switch. Check with governing authorities.

When servicing a unit installed at altitudes above 2,000′ insure that it has been properly modified to operate at that altitude. See the sections on Gas pressure (Page 10), and pressure switches (Page 15) to obtain specific information for you particular installation altitude.

To check temperature rise,use the following procedure:

1. Place thermometers in supply and return air registers as close to furnace as possible, avoiding direct radiant heat from heat exchangers.

2. Operate furnace continuously for 15 minutes with all registers and duct dampers open.

3. Take reading and compare with range specified on rating plate.

4. If the correct amount of temperature rise is NOT ob- tained, it may be necessary to change blower speed. A higher blower speed will lower the temperature rise. A lower blower speed will increase the temperature rise.

NOTE: BEFORE CHECKING TEMPERATURE RISE BE CERTAIN THAT MANIFOLD PRESSURE IS PROPERLY ADJUSTED.

Air Flow

Temperature Rise Check

The blower speed MUST be set to give the correct air temperature rise through the furnace as marked on the rating plate. Temperature rise is the difference between supply and return air temperatures.

440 08 2011 00

ALLOWABLE TEMPERATURE RISE ALL MODELS

Model

50, 80 Mbtu 35°F − 65°F

75, 100 & 125 Mbtu 40°F − 70°F

Example:

Supply Temp. 170° Return Temp. 70° Temperature Rise 100° = Too High

Solution: Increase Blower Speed

Range

Service Manual

Single Stage Multi Position Furnace

ROOM THERMOSTATS

Room thermostats are available from several different manufactures in a wide variety of styles. They range from the very simple and inexpensive Bi−metallic type to the complex and costly electronic set−back type. They are simply a switch (or series of switches) designed to turn equipment (or components) “ON” or “OFF” at the desired conditions.

An improperly operating, or poorly located room thermostat can be the source of perceived equipment problems. A careful check of the thermostat and wiring must be made then to insure that it is not the source of problems.

Figure 10

THERMOSTAT

5 ft.

Thermostat Location

DRAFTS

SUN

SHIELD

LIGHT

LOCATION

The thermostat should not be mounted where it may be affected by drafts, discharge air from registers (hot or cold), or heat radiated from the sun or appliances. Never install in alcoves, bathrooms or bedrooms.

The thermostat should be located about 5 ft. above the floor in an area of average temperature, with good air circulation. Normally, an area in close proximity to the return air grille is the best choice.

Mercury bulb type thermostats MUST be level to control temperature accurately to the desired set−point. Electronic digital type thermostats SHOULD be level for aesthetics.

HEAT ANTICIPATORS

Heat anticipators are small resistance heaters built into most electric−mechanical thermostats. Their purpose is to prevent wide swings in room temperature during furnace operation.

In order to accomplish this, the heat output from the anticipator must be the same regardless of the current flowing through it. Consequently, most thermostats have an adjust-

ment to compensate for varying current draw in the thermostat circuit.

The proper setting of heat anticipators then is important to insure proper temperature control and customer satisfaction.

Figure 11

Subbase

The best method to obtain the required setting for the heat anticipator, is to measure the actual current draw in the control circuit (“W”) using a low range (0−2.0 Amps) Ammeter. (See Figure 11) After measuring the current draw, simply set the heat anticipator to match that value.

If a low range ammeter is not available, a “Clamp−on” type meter may be used as follows:

1. Wrap EXACTLY ten (10) turns of wire around the jaws of a clamp−on type ammeter.

2. Connect one end of the wire to the “W” terminal of the thermostat sub−base, and the other to the “R” termi- nal.

3. Turn power on, and wait approximately 1 minute, then read meter.

4. Divide meter reading by 10 to obtain correct anticipator setting.

Electronic thermostats do not use a resistance type anticipator. These thermostats use a microprocessor (computer) that determines a cycle rate based on a program loaded into it at the factory.

These cycle rates are normally field adjustable for different types to equipment. The method of adjustment, however, varies from one thermostat manufacturer to another. Check with the thermostat manufacturer to find out the proper way of adjusting the cycle rate.

Measuring Current Draw

Amps

Ammeter

Control wiring is an important part of the total equipment installation, since it provides the vital communications link between the thermostat, and the equipment. Control wiring that is either too long, undersized, or improperly connected

CONTROL WIRING

(be it simply loose, or on the wrong terminal) can in fact be the source of many equipment problems.

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Service Manual

ALWAYS check to make sure that the control wiring is connected to the proper terminal(s) of the equipment and thermostat you are using. Remember, also, that the thermostat terminals are not always identified alike by different thermostat manufacturers. Connections MUST be clean and tight to insure trouble−free operation.

ELECTRONIC CONTROLS used on this series of furnace RESPOND DIFFERENTLY to certain control wiring practices which have been generally accepted in the HVAC industry for many years.

For Example: For years, installers have run a wire from the “Y” terminal of the room thermostat and connected it directly to the contact on coil of a condensing unit. (not making

TWINNING KITS

Some installations may require a Heating capacity or Airflow capabilities greater than a single furnace of this series can provide. When this is necessary, furnaces may be installed in a “Twinned” configuration.

The Twinning Kit allows the two (2) identical furnaces to be

LIMIT SWITCHES

Two (2) different kinds of limit switches are used on this series of furnaces. They are the main limit and roll out limit switch. The main limit, and roll limit switches are used on ALL models.

NOTE: All limit switches are safety devices and other than for testing purposes, should never be jumped out! Limit switches are “normally closed” electrical switches, designed to open when their predetermined “limit setting” has been reached.

It should also be remembered, that when a limit switch opens, it more than likely is not due to a bad switch! The cause of the opening limit must be found and corrected, before the furnace can resume proper operation.

FIRE HAZARD.

Failure to do so can result in death, personal injury and/or property damage.

Limit controls are factory preset and MUST NOT be adjusted. Use ONLY manufacturer’s authorized replacement parts.

any connection to the furnace with this wiring. Then, run the low voltage “Common” wire from the condensing unit back to the “C” terminal of the furnace.

With the electronic Furnace Control Board used in this series, however the “Y” terminal of the furnace does in fact serve a particular purpose. Failure to connect it will result in certain improper operation as follows:

The COOLING fan speed is energized via the “Y” terminal. Failure to connect the thermostat “Y” terminal to the “Y” terminal on the control will result in the failure to energize the COOLING speed on a call for cooling from the thermostat. (The HEATING speed will be energized instead via the “G” terminal)

controlled by the same room thermostat. When Twinned, the circulating (conditioned air) blowers of BOTH furnaces will operate simultaneously. The kit part no. for the “C” series or later furnace is NAHA004WK.

The specific functions of the two (2) limit switches used in this series of furnaces are as follows:

MAIN LIMIT SWITCH

There is a “Normally Closed” switch located on the front partition of the furnace. It monitors supply air temperature, and interrupts furnace (burner) operation when a supply air temperature is sensed which would result in the furnace exceeding Maximum allowable outlet air temperature. While the main limit is open, the combustion blower, and the circulating blower will be energized continuously. This control is an “Automatic” reset control, which will reset itself when the temperature sensed drops to a safe level.

If furnace (burner) cycles on this limit switch, (I.E. switch opens and closes during furnace operation) it is more than likely due to a high temperature rise through the furnace. (See checking temperature on page 10 of this manual)

High temperature rise can be caused by either OVER FIRING (high manifold pressure. incorrect orifices, etc.) or LOW AIR FLOW (dirty filter, blower speed too low, excessive static in duct system, etc.)

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

N9MP1 & N9MP2 MAIN LIMIT SWITCH

MODEL PA RT # OPEN CLOSE

050B12C 34335002 240° F 220° F

075B12C 34335001 210° F 190° F

080F16C 1320361 230° F 210° F

100F14C 1320361 230° F 210° F

100J20C 1320367 220° F 200° F

125J20C 1008445 190° F 170° F

ROLL OUT LIMIT SWITCH

MODEL PA RT # OPEN CLOSE

ALL 1013102 300° F MANUAL

*9MPD MAIN LIMIT SWITCH

MODEL PA RT # OPEN CLOSE

050B12C 1320366 260° F 240° F

075F12C 34335002 240° F 220° F

080J16C 1320367 220° F 200° F

100J14C 1320367 220° F 200° F

100J20C 1320367 220° F 200° F

125L20C 1008445 190° F 170° F

ROLL OUT LIMIT SWITCH

MODEL PA RT # OPEN CLOSE

ALL 1013102 300° F MANUAL

switch, use ONLY a switch of EXACTLY the same temperature setting. Use of a different temperature limit switch can create a dangerous situation. Some of the main limit switches used in this series are SIMILAR IN APPEARANCE. DIFFERENT TEMPERATURE SETTINGS, HOWEVER, ARE USED for different models. Be certain you have the correct control for the model you are servicing.

ROLL OUT LIMIT

A “Normally Closed” switch (wired in series with the Main Limit switch) mounted on both sides of the burner box.

This switch is a manual reset type. When replacing this switch, be absolutely certain the correct one is used.

Figure 12

Typical Roll Out Limit Switch

To verify this, the cut−out (opening) point of the switch should be checked (using a thermocouple type thermometer connected to the face of the switch) as follows:

1. Operate furnace for several minutes.

2. Block return air grille(s) to furnace.

3. Observe temperature at which switch opens (burner operation ceases).

4. Remove blockage from return grille(s).

5. Observe temperature at which switch closes (burner operation resumes).

6. Compare readings with the limit setting listed in the appropriate chart for the model you are servicing.

If switch is opening within the specified range, then it is simply doing its job, and the cause of the over−temperature must be determined and corrected.

If, however, the switch is found to be opening prematurely, then it should be replaced. When replacing ANY limit

PRESSURE SWITCHES

NEVER use an automatic reset roll out switch to replace a manual reset type roll out switch.

Doing so may cause potentially unsafe and/or intermittent operation.

The roll out switch monitors the temperature inside the burner box, and interrupts furnace (burner) operation when its temperature indicates flame roll out has occurred.

Once the roll out switch has opened, burner operation will be prevented until the roll out switch is “Manually Reset” by pressing the red button located on the switch. While the roll out switch is open, the combustion blower and circulating blower will be energized continuously.

If the roll out switch has opened, the cause must be determined. Some possible reasons for flame roll out include a restricted primary or secondary heat exchanger or over fired furnace.

CAUTION

Transition Pressure Switch

An air proving switch (pressure) switch is used on all models to insure that a draft has been established through the heat exchanger before allowing burner operation.

All models use a single tap (port) type switch. This switch senses the negative pressure created by (at) the combustion blower.

Under normal operating conditions, sufficient pressure is developed by the exhaust (combustion) blower to close the

440 08 2011 00

Single Stage Multi Position Furnace

Service Manual

switch, and permit the burner to operate. As the condensate drain begins to back−up, however, the pressure begins to reduce. When the pressure drops sufficiently, burner operation will be prevented until the condition is corrected.

N9MP1 STANDARD TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE″ W.C

050B12C 1013802 −2 −2.2

075B12C 1013802 −2 −2.2

080F16C 1013811 −1.6 −1.8

100F14C 1013801 −2.1 −2.3

100J20C 1013802 −2 −2.2

125J20C 1013166 −1.6 −1.8

N9MP1 STANDARD INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013166 −1.1 −1.3

N9MP1 HIGH ALTITUDE TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

050B12C 1013803 −1.8 −2

075F12C 1013803 −1.8 −2

080F16C 1013812 −1.3 −1.5

100F14C 1013803 −1.8 −2

100J20C 1013803 −1.8 −2

125L20C 1013157 −1.5 −1.7

N9MP1 HIGH ALTITUDE INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013157 −0.7 −0.9

Figure 13

Pressure Switch

Pressure Port

Normally Open Terminal

Common Terminal

N9MP2 STANDARD TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE″ W.C

050B12C 1013802 −2 −2.2

075B12C 1013801 −2.1 −2.3

080F16C 1013811 −1.6 −1.8

100F14C 1013801 −2.1 −2.3

100J20C 1013802 −2 −2.2

125J20C 1013166 −1.6 −1.8

N9MP2 STANDARD INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013166 −1.1 −1.3

N9MP2 HIGH ALTITUDE TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

050B12C 1013803 −1.8 −2

075F12C 1013803 −1.8 −2

080F16C 1013812 −1.3 −1.5

100F14C 1013803 −1.8 −2

100J20C 1013803 −1.8 −2

125L20C 1013157 −1.5 −1.7

N9MP2 HIGH ALTITUDE INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013157 −0.7 −0.9

*9MPD STANDARD TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE″ W.C

050B12C 1013802 −2 −2.2

075B12C 1013802 −2 −2.2

080F16C 1013812 −1.3 −1.5

100F14C 1013802 −2 −2.2

100J20C 1013802 −2 −2.2

125J20C 1013166 −1.6 −1.8

*9MPD STANDARD INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013166 −1.1 −1.3

*9MPD HIGH ALTITUDE TRANSITION SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

050B12C 1013803 −1.8 −2

075B12C 1013803 −1.8 −2

080F16C 1013813 −1 −1.2

100F14C 1013803 −1.8 −2

100J20C 1013803 −1.8 −2

125L20C 1013157 −1.5 −1.7

*9MPD HIGH ALTITUDE INDUCER SWITCH

MODEL PA RT # OPEN ″ W.C. CLOSE ″ W.C.

125J20C 1013157 −0.7 −0.9

440 08 2011 00

To insure continued SAFE, RELIABLE, operation NEVER SUBSTITUTE a pressure switch with one that is similar in

Service Manual

Single Stage Multi Position Furnace

appearance. ONLY FACTORY PROVIDED or AUTHORIZED SUBSTITUTES ARE ACCEPTABLE.

Furnaces installed at altitudes of 4,000′ above sea level or higher may require replacing the standard pressure switch with a high altitude pressure switch. The different pressure switch settings allow continued SAFE RELIABLE high altitude operation.

Under normal operating conditions, sufficient negative pressure will be created to close the pressure switch, and keep it closed to keep furnace operating. Under abnormal conditions, however, such as a restricted vent pipe, or a leak in one of the heat exchangers, sufficient negative pressure will not be created. This will result in the switch failing to close or failing to remain closed during furnace operation.

When servicing a unit whose pressure switch will not close, or remain closed during operation, the operating pressure of that furnace should be checked and compared to

Lower (Lesser) Negative Pressures

Lower than normal negative pressures measured at the Combustion Blower may be caused by:

1. Restriction on the Outlet side of the combustion blower. (I.E. Blocked Flue, Vent too long, Heat Exchanger leak, etc.)

approximate operating pressures listed in this manual and the switch setting(s) listed above for the model family you are servicing.

It is important to remember, that greater negative pressures are created by the furnace when “HOT” (I.E. upon initial start−up) than when “COLD” (I.E. after furnaces has been in operation for a few minutes). Because of this, furnace pressure should ONLY be checked when “HOT” to insure accurate readings.

The tables list approximate operating pressures. They are included in this manual to provide you with a “Barometer” to gauge your pressures against. The pressures you obtain in the field will differ slightly from these figures based upon vent length, gas pressure, operating temperature, etc.

Major discrepancies in pressures, will normally cause problems with pressure switch operation. These Major discrepancies should be investigated as follows:

2. Leak (lack of restriction) on the Inlet side of the com- bustion blower.

Higher (Greater) Negative Pressures

Higher than normal negative pressures measured at the Combustion Blower may be caused by:

1. Restriction on the Inlet side of the combustion blower. (I.E. Plugged Heat Exchanger, air inlet orifice too small)

Figure 14

*8″ Min. 20′ Max. in same atmospheric zone

Vent Pipes MUST be supported Horizontally and Vertically

Typical Upflow Installation

Aluminum or non−rusting shield recommended. (See Vent Termination Shielding for dimensions).

Coupling on ends of exhaust pipe. Total pipe & coupling outside structure = 8″

*8″ Min. 20′ Max. in same atmospheric zone

DISCHARGE AIR

Inlet Pipe (not used on Single Pipe model)

Figure 15 Typical Downflow Installation

See Vent Termination Shielding in Vent Section.

*8″ Min.

Inlet Pipe (not used on Single Pipe model)

Vent Pipes MUST be supported Horizontally and Vertically

* Increase minimum from 8″ to 18″ for cold climates (sustained temperatures below 0°F).

20′ Max. in same atmospheric zone

Coupling on inside and outside of wall to restrain vent pipe

*8″ Min. 20′ Max. in same atmospheric zone

25−23−33a

8″ Min.

* Increase minimum from 8″ to 18″ for cold climates (sustained temperatures below

0 °F).

25−23−33

440 08 2011 00

Single Stage Multi Position Furnace

VENT/COMBUSTION AIR PIPING

Service Manual

Vent and combustion air piping are an extremely important part of the total furnace installation. Improperly installed or inadequately sized vent and/or combustion air piping can be the source of many perceived furnace problems.

For example, most problems associated with pressure switch operation can normally be traced to short comings in the vent and/or combustion air piping. Anytime these type problems arise, a thorough inspection of the vent and/or combustion air piping should be conducted.

ALL MODELS require a vent (exhaust) pipe to carry flue

STANDARD VENT TERMINATION

Vent/Combustion Air Piping Charts

Sizing Combustion Air and Vent Pipe

Consult Table 9 or Table 10 to select the proper diameter exhaust and combustion air piping. Exhaust and combustion air piping is sized for each furnace Btuh size based on total lineal vent length (on inlet or outlet side), and number of 90° elbows required. Two 45° elbows can be substituted for one 90° elbow. The elbow or elbows used for vent termination outside the structure ARE counted, including elbows needed to bring termination above expected snow levels. The elbow inside the furnace on the *9MPD IS NOT included in the count.

Table 9

50,000, 75,000 & 80,000 Btuh Furnaces

40′ & (5) 90° elbows with 2″ PVC pipe or

70′ & (5) 90° elbows with 3″ PVC pipe

40′ & (5) 90° elbows with 3″ PVC pipe or 70′ & (5) 90° elbows with 3″ PVC pipe &

Long Vent Kit (See Tech. Manual)

40′ & (5) 90° elbows with 3″ PVC pipe

Elbows are DWV Long Radius Type for 2″ and 3″ vents.

If more than five elbows are required, reduce the length of both the inlet and exhaust pipes 5′ for each additional elbow used.

NOTE: It is allowable to use larger diameter pipe and fitting than shown in the tables but not smaller diameters than shown.

Pipe Diameter Table

N9MP1 & *9MPD Models

100,000 Btuh Furnace

125,000 Btuh Furnace

products to the outside of the structure. Direct VENT (ONLY) models require a combustion air inlet

to bring in all air for combustion from outside the struc- ture.

DUAL CERTIFIED models require a combustion air inlet pipe to bring in all air for combustion from outside the structure only when installed as a Direct Vent Furnace (I.E. Two Pipe Installation)

Consult the appropriate Venting tables and/or piping chart for the model you are servicing.

Table 10

50,000 & 80,000 Btuh Furnaces

40′ & (5) 90° elbows with 2″ PVC pipe or

70′ & (5) 90° elbows with 3″ PVC pipe

25′ & (3) 90° elbows with 2″ PVC pipe or

40′ & (5) 90° elbows with 2″ PVC pipe &

Long Vent Kit (See Tech. Manual) or

70′ & (5) 90° elbows with 3″ PVC pipe

40′ & (5) 90° elbows with 3″ PVC pipe or

70′ & (5) 90° elbows with 3″ PVC pipe &

Long Vent Kit (See Tech. Manual)

40′ & (5) 90° elbows with 3″ PVC pipe

Elbows are DWV Long Radius Type for 2″ and 3″ vents.

If more than five elbows are required, reduce the length of both the inlet and exhaust pipes 5′ for each additional elbow used.

NOTE: It is allowable to use larger diameter pipe and fitting than shown in the tables but not smaller diameters than shown.

Pipe Diameter Table

N9MP2 Models

75,000 Btuh Furnaces

100,000 Btuh Furnace

125,000 Btuh Furnace

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

Figure 16

Item Clearance Description Canadian Installation (1)

A Clearance above grade, veranda, porch, deck, balcony, or

anticipated snow level

B Clearance to a window or door that may be opened 6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 12″ (30

C Clearance to a permanently closed window

D Vertical clearance to a ventilated soffit located above the

terminal within a horizontal distance of 2′ (61cm) from the centerline of the terminal

E Clearance to an unventilated soffit

F Clearance to an outside corner

G Clearance to an inside corner

H Clearance to each side of the centerline extended above

electrical meter or gas service regulator assembly

I Clearance to service regulator vent outlet 3′ (91 cm)

J Clearance to non−mechanical air supply inlet to building or the

combustion air inlet to any other appliance

K Clearance to a mechanical air supply inlet 6′ (1.83 m) 3′ (91 cm) above if within 10′ (3m) horizontally

L Clearance under a veranda, porch, deck, or balcony 12″ (30 cm) +

M Clearance to each side of the centerline extended above or

below vent terminal of the furnace to a dryer or water heater vent, or other appliance’s direct vent intake or exhaust.

N Clearance from a plumbing vent stack 3′ (91 cm) 3′ (91 cm)

O Clearance above a paved sidewalk or paved driveway located

on public property.

(1. ) In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code

(2. ) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code

# 18″ (46 cm) above roof surface

+ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.

Direct Vent Termination Clearance

12″ (30cm) # 12″ (30 cm)

cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,000 Btuh (30 kW), 36″ (91 cm) for appliances > 100,000 Btuh (30 kW)

VENT TERMINAL

* *

3′ (91 cm) within 15′ (4.5 m) above the meter/regulator assembly

6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 9″ (23 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,000 Btuh (30 kW) and ≤ 50,000 Btuh (15 kW), 12″ (30 cm) for appliances > 50,000 Btuh (15 kW)

12″ (30 cm) 12″ (30 cm)

7′ (2.13 m) 7′ (2.13 m)

AIR SUPPLY INLET

AREA WHERE TERMINAL IS NOT PERMITED

6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 9″ (23 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 50,000 Btuh (15 kW), 12″ (30 cm) for appliances > 50,000 Btuh (15 kW)

3′ (91 cm) within 15′ (4.5 m) above the meter/regulator assembly

U.S. Installation (2)

25−24−65−2

6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 9″ (23 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 50,000 Btuh (15 kW), 12″ (30 cm) for appliances > 50,000 Btuh (15 kW)

* For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clearances shall be in accordance with local installation codes and the requirements of the gas supplier and the

manufacture’s installation instructions.

** A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

Notes:

1. The vent for this appliance shall not terminate a. Over public walkways; or b. Near soffit vents or crawl space vents or other areas where condensate or vapor could create a nuisance or hazard or property damage; or c. Where condensate vapor could cause damage or could be detrimental to the operation of regulators, relief valves, or other equipment.

2. When locating vent terminations, consideration must be given to prevailing winds, location, and other conditions which may cause recirculation of the combustion products of adjacent vents. Recirculation can cause poor combustion, inlet condensate problems, and accelerated corrosion of the heat exchangers.

440 08 2011 00

Single Stage Multi Position Furnace

Service Manual

Figure 17

Item Clearance Descriptions Canadian Installation (1)

A Clearance above grade, veranda, porch, deck, balcony, or

anticipated snow level

B Clearance to a window or door that may be opened 6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 12″ (30

C Clearance to a permanently closed window

D Vertical clearance to a ventilated soffit located above the ter-

minal within a horizontal distance of 2′ (61cm) from the cent- erline of the terminal

E Clearance to an unventilated soffit

F Clearance to an outside corner

G Clearance to an inside corner

H Clearance to each side of the centerline extended above elec-

trical meter or gas service regulator assembly

I Clearance to service regulator vent outlet 3′ (91 cm)

J Clearance to non−mechanical air supply inlet to building or the

combustion air inlet to any other appliance

K Clearance to a mechanical air supply inlet 6′ (1.83 m) 3′ (91 cm) above if within 10′ (3m) horizontally

L Clearance under a veranda, porch, deck, or balcony 12″ (30 cm) +

M Clearance to each side of the centerline extended above or

below vent terminal of the furnace to a dryer or water heater vent, or other appliance’s direct vent intake or exhaust.

N Clearance from a plumbing vent stack 3′ (91 cm) 3′ (91 cm)

O Clearance above a paved sidewalk or paved driveway located

on public property.

(1. ) In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code

(2. ) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code

# 18″ (46 cm) above roof surface

+ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.

Other than Direct Vent Termination Clearance

VENT TERMINAL

AIR SUPPLY INLET

12″ (30cm) # 12″ (30 cm)

cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,000 Btuh (30 kW), 36″ (91 cm) for appliances > 100,000 Btuh (30 kW)

* *

3′ (91 cm) within 15′ (4.5 m) above the meter/regulator assembly

6″ (15 cm) for appliances ≤ 10,000 BTUH (3kW), 12″ (30 cm) for appliances > 10,000 Btuh (3 kW) and ≤ 100,000 Btuh (30 kW), 36″ (91 cm) for appliances > 100,000 Btuh (30 kW)

* *

7′ (2.13 m) 7′ (2.13 m)

AREA WHERE TERMINAL IS NOT PERMITED

4′ (1.2 m) below or to the side of the opening. 1′ (30 cm) above the opening.

3′ (91 cm) within 15′ (4.5 m) above the meter/regulator assembly

4′ (1.2 m) below or to the side of opening: 1′ (30 cm) above opening.

25−24−65−2

U.S. Installation (2)

* For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clearances shall be in accordance with local installation codes and the requirements of the gas supplier and the manufacture’s

installation instructions.

** A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

Notes:

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

Figure 18

Inlet is optional on

Dual Certified models

A = 12″ Above roof or snow accumulation level

B = 8″ Min., 20′ Maximum, except in areas with extreme cold

temperatures (sustained below 0°F), the 18″ Min.

Figure 19

Inlet is optional on

Dual Certified models

Standard Termination Rooftop Termination

Sidewall Termination 12″ or More Above Snow Level or Grade Level

8 * MIN. 20’ MAX

*18″ Minimum for cold climates

(sustained below 0° F)

25−00−06

25−00−05F

Figure 21

Combustion

Dimension “A” is touching or 2″ maximum separation.

Figure 22

Inlet

12 Min. Grade

or Snow Level

Concentric Vent and Combustion− Air Sidewall Termination

1 Maximum

Air

Exhaust

Vent

(TYP.)

Vent

A"

25−22−02d

Sidewall Inlet Vent and Exhaust−Air Termination

A"

Ex-

haust

A"

8 Min.

20 Max.

18 Min. for

Cold Climates

(Sustained Below 0 F)

Dimension “A” is touching or 2″ maximum separation.

8

Min.

Figure 20

12 Min.

Grade or

Snow Level

Concentric Vent and Combustion-

Air Roof Termination

Exhaust

Combustion

Air

Dimension “A” is touching or 2″ maximum separation.

A"

Figure 23

18 Min. for Cold Climates

(Sustained Below 0 F)

Exhaust

Sidewall Inlet Vent and Exhaust−Air Termination with Exterior Risers

8

Inlet

Min.

12 Min.

Grade or

Snow Level

8 Min.

20 Max.

A"

Dimension “A” is touching or 2″ maximum separation.

440 08 2011 00

Single Stage Multi Position Furnace

Service Manual

Figure 24

18 Min. for Cold Climates

12 Min.

Grade or

Snow Level

Rooftop Inlet Vent and Exhaust−Air Termination

(Sustained Below 0 F)

Inlet

8 Min.

20 Max.

Exhaust

25−22−43

Figure 25

FRONT VIEW

Recommended Alternate Installation for Sustained Cold Weather (−0 F & below)

OVERHANG

12 MIN.

EXHAUST

90

INLET

12″ MIN. Ground

Level

OR Snow Level

SIDE VIEW

12″

25−23−73

CONCENTRIC VENT TERMINATION

Vent/Combustion Air Piping Charts

Figure 26

/2

Model A* B C D**

NAHA001CV 387/

NAHA002CV 333/

* = Dimension will change accordingly as dimension D is

lengthened or shortened.

** = Dimension D may be lengthened to 60″ may also be

shortened by cutting the pipes provided in the kit to 12″ minimum

Concentric Vent Dimensional Drawing

B PVC Vent/Exhaust

B PVC Intake/Combustion Air

3 41/

2 31/

25−22−03

211/

167/

Same Joist

Space

Concentric Termination Kit

Table 11

NAHA001CV & NAHA002VC Venting

Table for *9MPD

50,000 & 75,000 Btuh Furnaces

NAHA002CV − 35′ & (4) 90° elbows with 2″ PVC pipe NAHA001CV − 65′ & (4) 90° elbows with 3″ PVC pipe

1. Do not include the field supplied 45° elbow in the total elbow count.

2. If more than four elbows are required, reduce the length of both the inlet and the exhaust pipes five feet for each additional elbow used.

3. Elbows are DWV long radius type for 2″ and 3″ vents.

NOTE: Feet of pipe is whichever pipe run is the longest, either inlet or outlet side.

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

Figure 27

Concentric Vent Roof Installation

Vent

Maintain 12″ min. clearance

above highest anticipated

snow level. Max. of 24″ above

Combustion

roof.

Air

Roof Boot/

Flashing

(Field Supplied)

Support

(Field Supplied)

45° Elbow

(Field Supplied)

Vent

Combustion Air

25−22−02Note:

Support must be field installed to secure termination kit to structure.

COMBUSTION BLOWER

Figure 29

Rubber Coupling & Clamps

Proper Sealing Procedure for Combustion Blower

Vent Pipe (Top Panel Exit)

Vent Pipe

PVC Vent Extension Pipe

Figure 28

3″ x 2″ Bushings or 3″ x 21/2″ Bushings

If 3″ vent not used

Concentric Vent Sidewall Attachment

Strap

(Field Supplied)

Combustion

Air

(Field supplied)

Vent

Combustion

Air

45° Elbow

Vent

Flush to 1″ max.

(Field Supplied)

Note:

Securing strap must be field installed to prevent movement of termination kit

25−22−02

in side wall.

All models use an induced draft exhaust (combustion) blower mounted on the outlet side of the secondary heat exchanger. The purpose of the combustion blower is to establish a draft (flow) through the heat exchangers, to insure that all flue products are carried outside the structure via the vent pipe. The blower is made of plastic, and is driven by a permanent split capacitor motor.

Figure 29 shows the method of connection the vent pipe to the exhaust blower.

90 Street Elbow

Gutter

TOP

Vent Extension Pipe (Side Panel Exit)

SIDE VIEW

Rotate downward 5 to 10

NOTE: Built−in channel will be angled 5° to 10° also.

Vent Fitting & Clamps

Combustion Blower

25−23−35

440 08 2011 00

Single Stage Multi Position Furnace

CONDENSATE DRAIN TRAP

This furnace removes both sensible and latent heat from the products of combustion. Removal of the latent heat results in condensation of the water vapor. The condensate is removed from the furnace through the drains in the plastic transition and the vent fitting. The drains connect to the internally mounted condensate drain trap.

The startup of a new furnace will involve a cycle or two of the furnace to properly prime the condensate trap with water. Until the trap is fully primed, some condensate will be pulled into the combustion blower. The furnace may cycle on the pressure switch connected to the plastic transition box due to condensate buildup. After the trap is primed, the condensate will start draining from the furnace. The combustion blower will clear out any remaining condensate in the blower housing through the vent fitting downstream of the blower. Note that the condensate trap can also be primed by pouring water into the 1/2″ drain hose. Remove the1/2″ ID drain hose from either the gutter or the white PVC Tee Trap. Using a funnel pour eight (8) ounces of water into 1/2″ ID drain hose.Water will flow through the drain hose and into the condensate drain trap. This will prime both the vent and the transition sides of the trap. Reconnect the 1/2″ ID drain hose to the original component, either the gutter or the PVC Tee Trap.

The condensate drain trap supplied with the furnace MUST be used. The drain connection on the condensate drain trap is sized for 3/4″ PVC or CPVC pipe, however alternate 1/2″ CPVC (nominal 5/8″ O.D.) or vinyl tubing with a minimum inner diameter (I.D.) of 5/8″ may also be used, as allowed by local codes. Alternate drain pipes and hoses may be used as allowed by local codes.

The drain line must maintain a 1/4″ per foot downward slope toward the drain. 1/4″ per foot is recommended. Installation of an overflow line is recommended when the 1/4″ per foot slope to the condensate drain cannot be maintained.

DO NOT trap the drain line in any other location than at the condensate drain trap supplied with the furnace.

Service Manual

FROZEN AND BURST WATER PIPE HAZARD

Failure to do so may result in burst water pipes, serious property damage.

If a condensate pump is installed, a plugged condensate drain or a failed pump may cause the furnace to shut down. Do not leave the home unattended during freezing weather without turning off water supply and draining water pipes or otherwise protecting against the risk of frozen pipes.

If possible, DO NOT route the drain line where it may freeze. The drain line must terminate at an inside drain to prevent freezing of the condensate and possible property damage.

1. A condensate sump pump MUST be used if required by local codes, or if no indoor floor drain is available. The condensate pump must be approved for use with acidic condensate.

2. A plugged condensate drain line or a failed condensate pump will allow condensate to spill. If the furnace is installed where a condensate spill could cause damage, it is recommended that an auxiliary safety switch be installed to prevent operation of the equipment in the event of pump failure or plugged drain line. If used, an auxiliary safety switch should be installed in the R circuit (low voltage) ONLY.

3. If the auxiliary switch in the condensate pump is used, the furnace may shut down due to a blocked condensate line or failed pump. To prevent frozen water pipes see the “Frozen Water Pipe Hazard” section on Page 4 in the installation manual.

CAUTION

Condensate Drain Trap Freeze Protection

Special precautions MUST be made if installing furnace in an area which may drop below freezing. This can cause improper operation or damage to the equipment. If the the furnace environment has the potential of freezing, the drain trap and drain line must be protected. Use 3 to 6 watt per foot at 115 volt, 40° F self−regulating shielded and waterproof heat tape. Wrap the drain trap and drain line with the heat tape and secure with the ties. Follow the heat tape manufacturer’s recommendations.

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

Sequence of Operation & Diagnostics

The following is the normal operating sequence.

Cooling (Y) Request:

24VAC signals applied to Y & G terminals of FCB (furnace control board)

• Cool motor speed is energized after 5 second Cool Fan On Delay time.

Y & G signals removed from FCB

• Cool motor speed is de−energized after 90 second Cool Fan Off Delay time.

Continuous Circulating Fan (G) Request:

24 VAC signal is applied to G terminal of the FCB.

• Heat motor speed is energized without delay.

G signal removed from FCB.

• Heat motor speed is de−energized after 5 second delay.

NOTE 1) Furnace de−energizes the fan during the heat exchanger warm−up period on a call for Heating that occurs during a G request unless a blower motor lead is connected to the Cont terminal on the FCB, in which case see NOTE 2).

NOTE 2) Heating or Cooling requests received during a Fan request cause the fan speed to change to the appropriate heat or cool speed after the Fan on Delay time expires. The fan returns to continuous circulating speed after the selected Fan Off Delay time expires following loss of the Heating or Cooling request.

Continuous Circulating Fan Hard−Wired (Cont) Request:

Field selected low speed motor tap installed on “CONT” terminal.

• Low speed is energized when power applied to furnace. Operates at this speed continuously while there are no other blower demands from furnace control. Fan demands from furnace control for heat, cool or “G” will override hard−wired

speed tap.

NOTE 3) EAC is NOT active for hard−wired mode but IS active for fan demands from furnace control for heat, cool and “G”.

Heating (W) Request:

• 24 VAC signal applied to W terminal of FCB.

• Inducer motor turns on and the pressure switch(es) close(s).

• Following a 15 second prepurge delay, after the pressure switches closes, the igniter begins a 17 second warm−up.

• The gas valve is energized, the main burners light and flame is sensed.

• The igniter is de−energized after the main burners ignite.

• FCB will delay blower operation for the 30 seconds timed from the opening of the gas valve.

W signal removed from FCB.

• The gas valve de−energizes and the main burners go out.

• The inducer runs for a 15 second postpurge period.

• The fan stays at Heat speed.

• The fan de−energizes after the selected Heat Fan Off Delay time expires, timed from the gas valve de−energizing.

HUMIDIFIER − The 24V HUM is energized when the pressure switch closes on a call for heat. The 115V HUM (called HUM on Control) is energized when the inducer is energized.

ELECTRONIC AIR CLEANER − EAC is energized when there is a blower speed call. It is NOT energized when blower operates in the hard−wired continuous fan mode.

NOTE 4) If a new Heating request arrives while the control is waiting in the Heat Fan Off Delay time, the FCB will wait for the selected Heat Fan Off Delay then start a new heating cycle as long as the heat call remains.

440 08 2011 00

Single Stage Multi Position Furnace

Service Manual

Heating Request with Gas Shut Off:

24 VAC signal applied to W terminal of FCB. The FCB will attempt 4 cycles for ignition then go to soft lockout for 3 hours then try for ignition again as long as the heat call remains. Power reset will clear lockout.

• Inducer motor turns on

• Following a 15 second prepurge delay, the igniter begins warm up.

• The igniter glows red−hot for 22 seconds, then turns off. The FCB flashes error code 6.

• The igniter stays off for 17 seconds, then begins to warm up again.

• The igniter glows red hot for 22 seconds then turns off. The FCB continues flashing error code 6.

• The igniter stays off for 17 seconds, then begins to warm up again.

• The igniter glows red hot for 22 seconds then turns off. The FCB continues flashing error code 6.

• The igniter stays off for 17 seconds, then begins to warm up again.

• The igniter glows red hot for 22 seconds then turns off. The FCB proceeds to soft lockout and stops flashing error code

6 and begins flashing error code 6 + 1.

• The inducer motor de−energizes after a 15 second post purge.

Control Board Diagnostic Codes (See Figure 30)

OFF = 24VAC or 115VAC is off, fuse is open Heartbeat = Normal operation or no previous Diagnostic Code ON SOLID = Soft Lockout − Furnace Control Error (1 hr delay) If code repeats immediately following power reset then replace control 1 Flash = Not used 2 Flashes = Pressure switch(es) closed when should be open 3 Flashes = Pressure switch open when should be closed 4 Flashes = Limit or roll−out switch open (less than 2 minutes) 5 Flashes = Flame sensed out of sequence 6 Flashes = Failure to ignite or flame sense lost while running 6 + 1 Flashes = Soft Lockout − Max trials for ignition reached (3hr delay) 7 Flashes = Soft Lockout − Limit or roll−out switch open longer than 2 minutes (1 hr delay)

(roll−out switch requires manual reset) 8 Flashes = Permanent Lockout − Gas valve relay contact stuck closed or miswired gas valve (power reset only) 10 Flashes = Line voltage (115VAC) polarity reversed. If twinned, refer to twinning kit instructions

* If status code recall is needed, briefly (2−3 seconds) remove then reconnect one limit switch wire (main or rollout) to display last stored status code. Do not remove power or blower door before initiating status code recall or code will be lost. Code is automatically cleared after 72 hours or upon power reset.

* Proper flame sense microamps: 0.7 microamps D.C. minimum, 2.0 − 4.0 microamps nominal

Figure 30 Furnace Control Board

24 VAC HUM

Diagnostic Light

FUSE

440 08 2011 00

115 VAC HUM

Service Manual

Figure 31

Checking Flame Sensor

Single Stage Multi Position Furnace

CHECKING FLAME CURRENT

Flame Rectification is a process of converting Alternating Current (A.C.) into Direct Current (D.C.) During the ignition sequence, an alternating current (A.C.) Voltage is applied to the Flame sensor.

Wire From Flame Sensor Wire From Flame Sensor

Terminal of Ignition Control

2.0 μA

OhmsAC Volts

Micro

DC Volts

Amps

Common

The ignition system used in this furnace series prove (verify) flame via the Flame Rectification method.

CAPACITORS

Capacitors are used for the circulating (conditioned air) blower motor. Before replacing this motor (assumed to be bad) the condition of its capacitor should be verified, since it, and not the motor, may be the source of the problem.

Before checking any capacitor, the supply power to the unit should be turned “OFF”. The capacitor should then be discharged before testing. This can be done by shorting the capacitor leads together.

The condition of the capacitor should then be verified with a capacitor analyzer (one that indicated the capacitor’s value in microfarads) rather than with an Ohmmeter. The reason for this, is that an Ohmmeter test can only indicate if a capacitor is “OPEN’, or “SHORTED”, it cannot verify if its value (microfarads) is within an acceptable range.

Capacitor should test to within 10% of its rated value. Capacitors testing outside this range should be replaced. A weak capacitor can be the cause of a motor failing to start.

When the burner lights, the flame conducts an electrical current between the flame sensor and the burner ground. Due to the difference in size between the flame sensor and the burner ground area, this current flows mostly in one direction. This creates a pulsating Direct Current that flows back to the ignition control proving flame.

This flame current (D.C. Microamps) may be checked (while flame is present) using a D.C. Microampmeter IN SERIES (see Figure 31 ) with the flame sensor circuit. Flame current should be a minimum of 0.7 μA D.C.

Lower than normal readings will not keep flame established, and may be due to flame not properly enveloping sensor, dirty sensor, low gas pressure or pilot flame, etc.

The normal current for the flame sensor of this series furnace should be a nominal value of 2.0 −4.0 μA D.C.

Figure 32

Checking Capacitor

Microfarads

5 μp

100

μƒ

10 μƒ

1000

μƒ

10000 μƒ

All models use a multi−speed, permanent split capacitor motor, direct−drive, blower assembly. Different size (HP) motors and/or different diameter blower wheels are used in each model to obtain the required air flow. The entire blower assembly slides out on rails for servicing after removing the two screws at the front and disconnecting the harness connectors from the furnace control board.

BLOWER ASSEMBLY

SELECTING BLOWER SPEEDS

The wide variety of applications and installations of furnaces throughout the country makes it impossible to “Factory Select” blower speeds that will provide proper operation for all installations. This means then, that the blower speeds for both heating and cooling must be “Field Se-

440 08 2011 00

Single Stage Multi Position Furnace

Service Manual

lected” for each particular installation to insure proper operation.

The criteria for selecting the proper blower speeds IS NOT “High for Cooling, Low for Heating”. Although that may be how it works out SOMETIMES, it can (in many cases) be exactly the opposite. (I.E. a Lower speed for Cooling, and a Higher speed for Heating)

The PROPER CRITERIA FOR SELECTING BLOWER SPEEDS is as follows:

HEATING

A blower speed must be selected that will provide proper temperature rise through the furnace. (See “checking temperature rise” found elsewhere in this manual), The required CFM for a particular temperature rise can also be calculated using the following formula:

Output BTU

Temp. Rise X 1.08 = CFM

EXAMPLE: using a 75 Mbtu furnace with an output of 67,500 Btuh (90% x 75000) and a desired temperature rise of 50° F (range of 40−70° F allowable) and a measured external static pressure of 0.2″ W.C. with a dry coil.

67,500 or 67,500 50 X 1.08 54 = 1250 CFM

Checking the blower performance data for this model, (see Table 12) indicates that @ 0.2″ W.C. E.S.P. medium−high speed will deliver 1249 CFM. Accordingly, medium speed should be used in this example for the HEATING speed.

COOLING

A blower speed must be selected that will provide proper air flow (Nominal 400 CFM per ton) for the size (capacity) air conditioning coil being used at the external static pressure of the Duct system (installation). This requires CHECKING THE EXTERNAL STATIC PRESSURE, then consulting the BLOWER PERFORMANCE DATA to determine the required speed tap.

Using a manometer or magnehelic, take a pressure reading on the supply and return ductwork close to the furnace. The supply is positive while the return is negative. To find ESP add the supply and return readings together disregarding positive/negative.

EXAMPLE: The supply measurement is found to be 0.3″ W.C. while the return is measured at −0.2″ W.C. The ESP would be 0.5″ W.C.

EXAMPLE: A 24,000 BTU (2 TON) air conditioning system, using the same 75,000 BTU furnace as in the previous example. The external static pressure is measured and found to be 0.4″ W.C.

400 CFM (nominal) per TON required

400 x 2 = 800 CFM required

Checking the blower performance data (see Table 12) for this model indicates that @ 0.4″ W.C. ESP low speed will deliver 788 CFM. Accordingly, low speed should be used in this example for the COOLING speed.

Table 12

Blower Performance Data 75,0000 BTUH

Air Delivery in Cubic Feet per Minute (CFM)

(Furnace Rated @ 0.5″ W.C. ESP)

TAP LOW MED L MED H HIGH

.10 778 984 1263 1576

.20 786 1003 1249 1532

.30 790 1003 1244 1489

.40 788 1001 1215 1432

.50 781 982 1186 1371

Inches of W.C.

.60 765 962 1146 1308

External Static Pressure

.70 743 923 1094 1229

SAMPLE ONLY

Table 13 Blower Speed Chart

Wire Color Motor Speed

Black High

Orange* Med−High

Blue Medium

Red Low

*Med−High speed may not be provided on all models.

CHANGING BLOWER SPEEDS

1. Refer to Furnace Wiring Diagram for location of the heating and cooling speed taps located on the furnace control as well as location of unused blower motor speed leads. Use the chart (Table 13) to determine the blower motor speed settings.

2. Change the heat or cool blower motor speed by removing the motor lead from the “Heat” or “Cool” terminal and re- place it with the desired motor speed lead from the “Unused Motor Lead” location. Connect the wire previously removed from the “Heat” or “Cool” terminal to the vacated “Unused Motor Lead” terminal.

3. If the same speed must be used for both heating and cooling, remove the undesired motor speed lead from the “Heat” or “Cool” terminal and connect that lead to the open terminal at “Unused Motor Lead” location. Attach a jumper between the “Heat” and “Cool” terminals and the remaining motor speed lead.

Note: For motors with (4) speed leads, it will be necessary to tape off the terminal of the motor speed lead removed from the “Heat” or “Cool” terminal with electrical tape since an open terminal will not be available at the “Unused Motor

Lead” location.

“M1” & “M2” TERMINALS

There are two (2) terminals (marked “M1 and M2” on the Furnace Control Board, which have no internal connection to the control. Their purpose is to provide a place to connect any “UNUSED” speed tap wires to keep them out of the way and prevent them from shorting out against the furnace casing, or each other.

440 08 2011 00

Service Manual

Single Stage Multi Position Furnace

Continuous−Fan Operation using G"

Energizing the “G” terminal on the furnace control provides continuous fan operation. This is done by connecting the G terminal of the thermostat to the G terminal on the furnace control. When the FAN switch is turned from auto to ON the fan will operate continuously at “HEAT” speed. EAC will be energized in this mode.

NOTE: In heating, the fan will turn off during furnace ignition and warm up then restart at heating speed.

Hard Wired Continuous Fan Operation

A terminal is provided on the furnace control board located in the circulating blower compartment for operation of the continuous fan option. This connection is intended for the low speed motor tap, and has a lower contact rating (8 amps) than the heat and cool taps. When the low speed blower lead is connected to this terminal, this will provide low speed blower operation whenever the other two speeds (Heat or Cool) are not energized.

Thoroughly check the system after modification to ensure the proper operation of the circulating air blower in all modes of operation.

Separate speed selections for Heat, Cool, and Continuous Fan

Connect low speed lead from circulating motor to the “Cont.” terminal at the furnace control. The appropriate motor leads should already be connected to the “Heat” and “Cool” terminals.

Heating and Continuous Blower Speed the Same

If it is necessary to operate the heating speed and continuous blower speed using the same blower speed, connect a jumper between the ”Heat” and ”Cont.” terminals on the furnace control.

Note: There should be only ONE motor lead going to the “Heat” and “Cont.” terminals.

REDUCED FURNACE LIFE HAZARD

Failure to properly set the air temperature rise may result in reduced furnace life.

Use ONLY the following blower motor speed taps for setting air temperature rise.

Blower Motor Speed Taps Model Sizes

Hi (BLK) All Med−Hi (O) All Med Lo (BL) DO NOT USE

Lo (RED) DO NOT USE

CAUTION

440 08 2011 00

CIRCULATION AIR BLOWER DATA

For 050 Models 3 Ton Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 826 1083 1301 1408

0.2 804 1050 1242 1347

0.3 770 1028 1195 1295

0.4 735 985 1153 1237

0.5 698 952 1093 1183

0.6 657 909 1040 111 8

0.7 −−− 863 935 1053

0.8 −−−− 812 865 976

0.9 −−− −−− 802 887

1.0 −−− −−− 720 787

For 075 Models 3 Ton Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 706 917 1163 1368

0.2 677 875 1120 1319

0.3 636 840 1076 1263

0.4 595 812 1031 1202

0.5 546 766 987 1148

0.6 490 702 889 1077

0.7 −−− 630 821 989

0.8 −−− 550 750 914

0.9 −−− 462 676 833

1.0 −−− −−− 601 747

For 100 Models 3.5 Ton 19 & 223/4 Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 700 912 1209 1550

0.2 660 884 1171 1492

0.3 616 843 1139 1434

0.4 575 790 1088 1378

0.5 528 735 1040 1317

0.6 472 677 979 1247

0.7 −−− 608 909 1161

0.8 −−− 528 827 1058

0.9 −−− −−− 733 932

1.0 −−− −−− 624 778

For 080 Models 4 Ton 19 & 223/4 Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 823 1109 1527 1850

0.2 795 1087 1482 1791

0.3 747 1056 1426 1720

0.4 677 1016 1382 1648

0.5 617 970 1317 1575

0.6 544 854 1245 1485

0.7 −−− 763 1154 1401

0.8 −−− 652 1043 1284

0.9 −−− −−− 905 1161

1.0 −−− −−− 737 1028

For 100 Models 5 Ton 223/4 Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 1682 1870 2081 2263

0.2 1654 1826 2031 2193

0.3 1597 1775 1963 2165

0.4 1547 1719 1899 2056

0.5 1498 1653 1825 1978

0.6 1428 1583 1737 1854

0.7 1355 1503 1650 1757

0.8 1267 1392 1548 1644

0.9 −−− 1266 1428 1515

1.0 −−− −−− −−− 1351

For 125 Models 5 Ton Units

Exterrnal Static Pressure

Inches of W.C.

Speed

Tap

Low Med L Med H Hi

0.1 1720 1910 2127 2315

0.2 1686 1881 2087 2268

0.3 1644 1833 2024 2201

0.4 1600 1777 1961 2131

0.5 1533 1720 1891 2029

0.6 1494 1647 1804 1948

0.7 1413 1571 1708 1820

0.8 1306 1470 1604 1730

0.9 −−−− 1349 1484 1614

1.0 −−−− −−−− 1328 1430

440 08 2011 00

Wiring Diagram

WARNING: ELECTRICAL SHOCK HAZARD

DISCONNECT BEFORE SERVICING

CONNECTION DIAGRAM

LADDER DIAGRAM

COOL ON DELAY: 5 SEC COOL OFF DELAY: 90 SEC HEAT ON DELAY: 30 SEC

FURNACE CONTROL J1

330709-101 REV. B

BVSS

(WHE N USE D)

CAPACITOR

TRANSFORMER

SENSOR

PRESSURE SWITCH

1 TO 2 IN S E R IES

DEP ENDING O N MODE L

LP PR ESS URE

SWITCH

(WHE N USE D)

GRN/Y

IGNIT ER

COPPER CONDUCTORS

ONLY

HOT

NEUT RAL

GND

JUNCTION

BOX

INTE R LOCK SWITCH

NOTE #3

NOTE #8

TO 115VAC FIELD DIS CONNE CT

NOTE #2

GRN/Y

COLOR CODE

BLACK

BLUE

BROWN

GREEN/YELLOW

ORANGE

RED

WHITE

YELLOW

SPEED TAP CODE

BLACK HI

ORANGE MHI

BLUE MLO

RED LO

CAPACITOR

(SO ME MODE LS)

LP PRESS. SWITCH

(LP MODELS ONLY )

PRESS URE SWITCH

1 TO 2 IN S E R IES

DEP ENDING O N MODE L

ROLLOUT S WITCH 1 TO 3

IN S ER IES DEPE NDING

ON MODEL

NEUT RAL

EQUIPMENT GROUND

XFMR

TRANSFORMER

115VAC

24VAC

COM

NOTE #6

FUSE 5A

GAS

VALVE

RELAY

PRINTED

CIRCUIT BOARD

NOTE #5

SENSOR

NOTE #3

P1-10

P1-11

INDUC ER

RELAY

HEAT/COOL

RELAY

BLOWER

RELAY

CAPACITOR

MAIN LI MIT

HUM

CONT FAN

(OPT )

MLO ( BL )

COM

IGNIT ION

RELAY

IGNIT ER

BVSS

(FIE LD INS TALLE D)

HOT

CAPACITOR

(SO ME MODE LS)

DIAGNOS TIC

LED

24VAC

COM

140 S E C.

100 S E C.

180 S E C.

ROLLOUT SWITCH 1 TO 2

IN SERIES DEPENDING

ON MODEL

MAIN LIMIT

HEAT

OFF-DELAY

5-AMP

100

180

140

HUM

NOTE:

1. If any of the original equipment wire is replaced use wire rated 105º C.

2. Use only copper wire between the disconnect switch and the furnace

junction box.

3. This wire must be connected to furnace sheet metal for control to

prove flame.

4. Symbols are electrical representation only.

5. Solid lines inside circuit board are printed circuit board traces and are

not depicted as shown in the legend.

6. Replace only with a 5 amp fuse.

7. Blower motor speed selections are for average conditions, see

installation instructions for details on optimum speed selection.

8. Factory connected when LP Pressure Switch and BVSS (Chimney

Adapter Accessory Kit) are not installed.

9. Blower off-delay, gas heating selections are (60, 100, 140, and 180)

seconds, cooling or heat pump 90 seconds.

10. Ignition lockout will occur after four consecutive unsuccessful trials for

ignition. Control will auto-reset after three hours.

11. Blower motor and inducer motor contain internal auto-reset thermal

overload switches.

12. Flame sensor: 0.7 μA D.C. minimum, 2.0 - 4.0 μA nominal.

13. Depending on model, P4 inducer motor leads may be in a single connector

or two quick connecters.

XFMR

HUM

CONT

FAN

EAC

M2 M1

HEAT

COOL

INTE R LOCK

SWITCH

HI (BK)

HEAT

COOL

EAC

P1-6

P1-4

P1-8

P1-2

P1-3

P1-1

P1-5

P1-9

P1-7

HEAT

OFF-DELAY

100

180

60 140

60 S E C.

HEAT

OFF-DELAY

100

180

140

HEAT

OFF-DELAY

100

180

140

HEAT

OFF-DELAY

100

180

60 140

BKBLBR

GRN/YORWY

NEUT RALS

LO (R)

CONTROL BOARD

24VAC

MHI (O )

LOW VOLTAGE FACTOR Y

LOW VOLTAGE FIELD

LINE VOLTAGE F ACTOR Y

LINE VOLTAGE F IELD

CONDUCTOR ON CONTROL

JUNCTION

UNMARKE D TE R MINAL

CONTROL TERMINAL

PSC

BLOWER

MOT OR

INDUC ER

MOT OR

INDUC ER

MOT OR

PSC

BLOWER

MOT OR

115VAC

24VAC

NOTE #8

HUM 24 VAC

CPU

EAC + HUM 1.0A MAX

COMBINED

NOTE #12

RED BLUE

NOTE #12

NOTE #13

GAS

VALVE

GAS

VALVE

NOTE #2

HSI

IND

NOTE #13

24 VAC

440 08 2011 00

Model Specifications

Manufacturers Number (Mfr No −See Rating Plate) ALL Models

Specifications (N9MP1)

N9MP1050B12C N9MP1075B12C N9MP1080F16C N9MP1100F14C N9MP1100J20C N9MP1125J20C

General

Gas Type Input (Btuh) Output (Btuh) Transformer Size (VA) T’stat Heat Anticipator Temp. Rise (

Nat./ LP

50,000 45,500

.50

35−65

Nat./ LP

75,000 68,000

.50

40−70

Nat./ LP

80,000 72,000

.50

35−65

Nat./ LP 100,000

91,000

.50

40−70

Nat./ LP 100,000

96,500

.50

40−70

Nat./ LP 125,000 113,750

.50

40−70

Electrical (Volts/Hz/FLA) 115/60/9.8 115/60/8.9 115/60/9.0 115/60/9.0 115/60/10.5 115/60/11.2

Rating Plate Amps 12.9 10.1 12.9 10.1 14.4 15.0

Gas & Ignition

Gas Type

Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P.

Gas Valve (Honeywell) Regulation Type IgnitionType/Series

VR 8205S

SNAP

Hot Surface

Manifold Press. (Inch’s WC) Std. Main Orifices (No/Size)

3.5

2/42

10.0 2/54

3.5

3/42

10.0 3/54

3.5

4/44

10.0 4/55

3.5

4/42

10.0 4/54

3.5

4/42

10.0 4/54

3.5

5/42

10.0 5/54

Furnace Controls

Furnace Control (Type ) Furnace Control On (Timed−secs) Off

Integrated

60,100,140,180

Combustion

Flue Outlet Size (Inches) Std. Outlet Temp (°5′ No Elbows)

<140

Blower Pressure 5′ No Elbows (″ WC) Blower Pressure 40′ +5−90° DWV Elbows (″ WC) Transition Bx Pressure 5′ No Elbows (″ WC) Transition Bx Pressure 40′ +5−90° DWV Elbows (″ WC)

−−

−2.6

−2.3

−−

−2.6

−2.3

−−

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

Limits & Controls

Rollout Switch (

Limit Control Setting (

300 240

300 210

300 230

300 220

300 190

Standard Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013802

−−

−2.2

−2.0

1013802

−−

−2.2

−2.0

1013811

−−

−1.8

−1.6

1013801

−−

−2.3

−2.1

1013802

−−

−2.2

−2.0

1013166

−1.3

−1.1

−1.8

−1.6

High Altitude Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013812

−−

−1.5

−1.3

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013157

−0.9

−0.7

−1.7

−1.5

Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

−−

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

−−

High Altitude Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA003LV

1013165

−0.7

−0.6

−1.4

−1.2

−−

Blower Data

Type & Size Motor Amps/Rpm Motor Type/H.p. Cap. Mfd/Volts Filter Type & Size (Permanent − not supplied) Cool Cap. (Tons) @ .5″ W.C. L, ML, MHi & Hi

11−8

10/850

PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−8

8.0/1050 PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−10 10/1050 PSC/

10/370

16x25x1

/2,3,31/2,4

11−10 10/1050 PSC/

10/370

16x25x1

/2,2,3,31/2,

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

Gas Conversion Kits

Nat to LP NAHA001LP (1172958*) LP to Nat NAHA001NG (1172960*)

*Order from Service Parts

440 08 2011 00

Manufacturers Number (Mfr No −See Rating Plate) ALL Models

Specifications (N9MP2)

N9MP2050B12C N9MP2075B12C N9MP2080F16C N9MP2100F14C N9MP2100J20C N9MP2125J20C

General

Gas Type Input (Btuh) Output (Btuh) Transformer Size (VA) T’stat Heat Anticipator Temp. Rise (

Nat./ LP

50,000 45,500

.50

35−65

Nat./ LP

75,000 68,000

.50

40−70

Nat./ LP

80,000 72,000

.50

35−65

Nat./ LP 100,000

91,000

.50

40−70

Nat./ LP 100,000

96,500

.50

40−70

Nat./ LP 125,000 113,750

.50

40−70

Electrical (Volts/Hz/FLA) 115/60/9.8 115/60/8.9 115/60/9.0 115/60/9.0 115/60/10.5 115/60/11.2

Rating Plate Amps 12.9 10.1 12.9 10.1 14.4 15.0

Gas & Ignition

Gas Type

Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P.

Gas Valve (Honeywell) Regulation Type IgnitionType/Series

VR 8205S

SNAP

Hot Surface

Manifold Press. (Inch’s WC) Std. Main Orifices (No/Size)

3.5

2/42

10.0 2/54

3.5

3/42

10.0 3/54

3.5

4/44

10.0 4/55

3.5

4/42

10.0 4/54

3.5

4/42

10.0 4/54

3.5

5/42

10.0 5/54

Furnace Controls

Furnace Control (Type) Furnace Control On (Timed−secs) Off

Integrated

60,100,140,180

Combustion

Flue Outlet Size (Inches) Std. Outlet Temp (°5′ No Elbows)

<140

Blower Pressure 5′ No Elbows (″ WC) Blower Pressure 40′ +5−90° DWV Elbows (″ WC) Transition Bx Pressure 5′ No Elbows (″ WC) Transition Bx Pressure 40′ +5−90° DWV Elbows (″ WC)

−−

−2.6

−2.3

−1.8

−1.3

−2.6

−2.3

−−

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

Limits & Controls

Rollout Switch (

Limit Control Setting (

300 240

300 210

300 230

300 220

300 190

Standard Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013802

−−

−2.2

−2.0

1013801

−−

−2.3

−2.1

1013811

−−

−1.8

−1.6

1013801

−−

−2.3

−2.1

1013802

−−

−2.2

−2.0

1013166

−1.3

−1.1

−1.8

−1.6

High Altitude Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013812

−−

−1.5

−1.3

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013157

−0.9

−0.7

−1.7

−1.5

Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

−−

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

NAHA001LV

1013518

−1.0

−0.8

−2.0

−1.8

−−

High Altitude Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA003LV

1013165

−0.7

−0.6

−1.4

−1.2

−−

NAHA003LV

1013165

−0.7

−0.6

−1.4

−1.2

−−

Blower Data

Type & Size Motor Amps/Rpm Motor Type/H.p. Cap. Mfd/Volts Filter Type & Size (Permanent − not supplied) Cool Cap. (Tons) @ .5″ W.C. L, ML, MHi & Hi

11−8

10/850

PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−8

8.0/1050 PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−10 10/1050 PSC/

10/370

16x25x1

/2,3,31/2,4

11−10 10/1050 PSC/

10/370

16x25x1

/2,2,3,31/2,

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

Gas Conversion Kits

Nat to LP NAHA001LP (1172958*) LP to Nat NAHA001NG (1172960*)

*Order from Service Parts

440 08 2011 00

Manufacturers Number (Mfr No −See Rating Plate) ALL Models

Specifications (*9MPD)

*9MPD050F12C *9MPD075F12C *9MPD080J16C *9MPD100J14C *9MPD100J20C *9MPD125L20C

General

Gas Type Input (Btuh) Output (Btuh) Transformer Size (VA) T’stat Heat Anticipator Temp. Rise (

Nat./ LP

50,000 46,000

.50

35−65

Nat./ LP

75,000 69,000

.50

40−70

Nat./ LP

80,000 73,600

.50

35−65

Nat./ LP 100,000

92,000

.50

40−70

Nat./ LP 100,000

92,000

.50

40−70

Nat./ LP 125,000 115,000

.50

40−70

Electrical (Volts/Hz) 115/60 115/60 115/60 115/60 115/60 115/60

Rating Plate Amps 12.9 10.1 12.9 10.1 14.4 15.0

Gas & Ignition

Gas Type

Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P. Nat. L.P.

Gas Valve (Honeywell) Regulation Type IgnitionType/Series

VR 8205S

SNAP

Hot Surface

Manifold Press. (Inch’s WC) Std. Main Orifices (No/Size)

3.5

2/42

10.0 2/54

3.5

3/42

10.0 3/54

3.5

4/44

10.0 4/55

3.5

4/42

10.0 4/54

3.5

4/42

10.0 4/54

3.5

5/42

10.0 5/54

Furnace Controls

Furnace Control (Type) Furnace Control On (Timed−secs) Off

Integrated

60,100,140,180

Combustion

Flue Outlet Size (Inches) Std. Outlet Temp (°5′ No Elbows)

<140

Blower Pressure 5′ No Elbows (″ WC) Blower Pressure 40′ +5−90° DWV Elbows (″ WC) Transition Bx Pressure 5′ No Elbows (″ WC) Transition Bx Pressure 40′ +5−90° DWV Elbows (″ WC)

−−

−2.6

−2.3

−−

−2.6

−2.3

−−

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

−1.8

−1.7

−2.6

−2.5

Limits & Controls

Rollout Switch (

Limit Control Setting (

300 260

300 240

300 220

300 190

Standard Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013802

−−

−2.2

−2.0

1013802

−−

−2.2

−2.0

1013812

−−

−1.5

−1.3

1013802

−−

−2.2

−2.0

1013802

−−

−2.2

−2.0

1013166

−1.3

−1.1

−1.8

−1.6

High Altitude Pressure Sw. (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013813

−−

−1.2

−1.0

1013803

−−

−2.0

−1.8

1013803

−−

−2.0

−1.8

1013157

−0.9

−0.7

−1.7

−1.5

Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA002LV

1013515

−1.0

−0.8

−1.7

−1.5

−−

NAHA002LV

1013515

−1.0

−0.8

−1.7

−1.5

−−

High Altitude Long Vent Kit (Part No) Pressure Switch (Part No)

Blower Switch Pressure (Close) (″ WC) Blower Switch Pressure (Open) (″ WC) Transition Switch Pressure (Close) (″ WC) Transition Switch Pressure (Open) (″ WC)

−−

NAHA003LV

1013165

−0.7

−0.6

−1.4

−1.2

−−

Blower Data

Type & Size Motor Amps/Rpm Motor Type/H.p. Cap. Mfd/Volts Filter Type & Size (Permanent − not supplied) Cool Cap. (Tons) @ .5″ W.C. L, ML, MHi & Hi

11−8

10/850

PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−10

8.0/1050 PSC/

7.5/370

16x25x1

/2,2,21/2,3

11−10 10/1050 PSC/

10/370

16x25x1

/2,3,31/2,4

11−10 10/1050 PSC/

10/370

16x25x1

/2,2,3,31/

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

11−10

13/900

PSC/

40/370

16x25x1

/2,4,41/2,5

Gas Conversion Kits

Nat to LP NAHA001LP (1172958*) LP to Nat NAHA001NG (1172960*)

*Order from Service Parts

−

Service Manual

Single Stage Multi Position Furnace

TROUBLESHOOTING GUIDE

SELF DIAGNOSTICS

Self Diagnostics (via an LED provided on the furnace control) assist the Technician with troubleshooting. If the LED is flashing, the trouble is LIKELY (see below) to be external to the control.

Certain failures of the furnace result in a specific Flash Sequence (see below) being displayed by the LED. The LED will Flash “ON” for approximately 1/4 second, then “OFF” for approximately 1/4 second a specific number of times indicating the problem area.

SELF DIAGNOSTICS

In the event of a failure, the LED may be seen flashing through the inspection window on the furnace blower door. The Flash Sequence should be noted (and recorded) BEFORE removing the blower door from the furnace. This will prevent the loss of a flash sequence created by an intermittent or sporadic condition.

Control Board Diagnostic Codes (See Figure 30)

* If status code recall is needed, briefly (2−3 seconds) remove then reconnect one limit switch wire (main or rollout) to display last stored status code. Code is automatically cleared after 72 hours or upon power reset.

* Proper flame sense microamps: 0.7 microamps D.C. minimum, 2.0 − 4.0 microamps nominal ** Igniter should measure between 40−70 OHMS at room temperature. *** As a matter of standard practice, Line Voltage POLARITY and GROUNDING (see Page 4) should be verified on ANY

unit indicating system lockout.

NOTE: The “Problems” listed for the Flash Sequence Indications above are NOT ABSOLUTES. They are generalities,

intended to steer the Technician in the right direction. Used with common sense and other established troubleshooting methods, however, should result in an accurate diagnosis of the problem.

NOTE: The flash code will be lost if the 115 VAC power is removed from the furnace.

440 08 2011 00

Single Stage Multi Position Furnace

Diagnostic Code Section

Service Manual

Heartbeat

NO PREVIOUS CODE − Stored codes are erased after 72 hours. Run system through a heating or cooling cycle to check system.

LED OFF

No power

− Check 5A furnace control fuse

− Check circuit breaker or fuse

− Check door switch.

− Check 115V and 24V wiring

ON Solid

CONTROL CIRCUIT LOCKOUT Auto− reset after 1 hour lockout due to:

− Flame circuit failure.

− Gas valve relay stuck open.

− Software check error. Reset power to clear lockout. Replace control if code repeats

2 PRESSURE SWITCH DID NOT OPEN −

Check for:

− Obstructed pressure tube.

− Pressure switch stuck closed.

3 PRESSURE SWITCH DID NOT CLOSE

OR REOPENED − If open longer than 5 minutes, inducer shuts off for 15 minutes before retry. If opens during blower on delay period, blower will come on for the selected blower off−delay. Check for:

− Proper vent sizing.

− Low inducer voltage (115V)

− Inadequate combustion air supply.

− Disconnected or obstructed pressure tubing

− Defective inducer motor.

− *LP Low pressure gas switch open

− Defective pressure switch.

− Excessive wind.

− Restricted vent.

4 LIMIT CIRCUIT FAULT − Indicates the limit, flame

rollout switch is open. Blower and inducer will run until open switch remakes. If open longer than 2 minutes, code changes to lockout #7. If open less than 2 min. status code #4 continues to flash until blower shuts off. Flame rollout switch requires manual reset. Check for:

− Dirty filter or restricted duct system.

− Loose blower wheel.

− Defective blower motor or capacitor.

− Inadequate combustion air supply (flame rollout switch open).

− Restricted vent.

− Proper vent sizing.

− Excessive wind.

5 FLAME−PROVING SIGNAL

Flame is proved while gas valve is de−energized. Inducer will run until fault is cleared. Check for:

− Stuck open or leaky gas valve.

6 IGNITION PROVING FAILURE − If flame is not

sensed during the trail for ignition period, the control will repeat the ignition sequence 3 more times before a lockout #6 + 1 occurs. If flame signal is lost during the blower on−delay period, blower blower will come on for the selected blower off delay. Check the following items first before proceeding to the next step

− Gas value turned ON.

− Open.

− Green/Yellow wire MUST be connected to furnace sheet metal.

− Flame sensor must not be grounded. To determine whether the problem is in the gas valve, igniter, or flame sensor.

6 + 1

IGNITION LOCKOUT − System failed to ignite gas and prove flame in 4 attempts. Control will auto−reset after 3 hours. See status code 6.

9 NOT USED ON SINGLE STAGE

10 Check for correct line voltage polarity. If

units are twinned. Check for proper low voltage (24V) transformer phasing.

* LP low pressure gas switch used in LP kit

440 08 2011 00

7 LIMIT CIRCUIT LOCKOUT − Lockout occurs if the

limit, flame rollout is open longer than 2 minutes. Control will auto−reset after 1 hour. See code 4.

8 GAS HEATING LOCKOUT − Turn off power and wait 5 minutes to retry. Check for:

− Stuck closed gas valve relay on control.

− Miswire or short to gas valve wire.

Service Manual

Single Stage Multi Position Furnace

Troubleshooting Chart #1

Start

Thermostat in “OFF” position. “Heartbeat” on Diagnostic LED

Place Thermostat fan switch in “ON” position

Does indoor blower run on Heat speed?

Yes

Is Diagnostic LED Flashing a Code?

Yes

Go to Diagnostics Code Section

Is there a “Heartbeat” on the Diagnostic LED?

No No

Yes

Are 24 Volts present across “R” and “C” terminals?

Yes

Are 115 Volts present across transformer primary terminals?

Yes

Check Transformer and wiring to control and 5A Fuse on Furnace Control Board

Replace Furnace Control Board control and re−check operation

Continuous Fan Operation Check

Check supply circuit

Are 24 Volts present across “C” and “G” terminals

Are 115 Volts present across HEAT Fan and Neutral Terminals

Return Thermostat fan switch to “AUTO” position

Go to Chart #2

Check blower Motor, capacitor and wiring

NOTE: Door switch must be taped closed to perform these checks. Remove tape when finished.

NOTE: A “Heartbeat” is defined as the diagnostics LED flashing continually from bright to dim.

Yes

Check Thermostat and thermostat wiring

Replace Furnace Control Board

440 08 2011 00

Single Stage Multi Position Furnace

Troubleshooting Chart #2

Service Manual

Start

Place Thermostat switch in “AUTO” position

Place Thermostat in “COOL” and calling for operation

Does indoor blower run on Cooling speed?

Yes

No No

Are 24 Volts present across “R” and “C” terminals?

Yes

Are 24 Volts present across “C” and “Y” terminals?

Yes

Are 115 Volts present across Cool and Neutral terminals?

Yes

Are 115 Volts present across transformer primary terminals?

Yes

Check Transformer

Check Thermostat and thermostat wiring

Replace Control Board

Cooling Cycle Operation Check

Check supply circuit

Does Condensing unit run

Yes

Place Thermostat in “OFF” removing call for operation

Does indoor blower shut down after Blower Off Delay? 90 seconds

Yes

Check Blower Motor, capacitor and wiring

Check Condensing unit control wiring & supply circuit

Indoor blower remains running continuously

Is Indoor Blower “Hard wired” for Continuous Fan Operation

Go to Chart #3

Yes

Replace Furnace Control Board

Replace Furnace Control Board IF “OFF” delay is required

Indoor blower shuts down immediately

Yes

Is “Y” Terminal of T−stat connected to control?

Yes

“Y” terminal MUST be connected to enable delay

NOTE: Door switch must be taped closed to perform these checks. Remove tape when finished. NOTE: A “Heartbeat” is defined as the diagnostics LED flashing continually from bright to dim.

440 08 2011 00

Service Manual

Continued from Chart #2

Place Thermostat in “HEAT” and calling for operation

Troubleshooting Chart #3

Is Diagnostic LED Flashing a Code

Refer to Diagnostic

Yes

Code Section

Single Stage Multi Position Furnace

Heating Cycle Operation Check

Does combustion blower run?

Yes

Does the igniter warm−up and glow red?

Yes

Does burner ignite?

Yes

Is Diagnostic LED Flashing a “Heart Beat”

Check pressure switch for Continuity

Replace Pressure Switch

Are 115 Volts present

across igniter terminals?

Check Igniter for Continuity

Replace igniter

Are 24 Volts present across Gas Valve terminals?

Yes

Are 24 Volts Present Across “R” and “C”

Are 115 Volts Present at Combustion Blower

Replace Combustion Blower

Is LED Flashing 3 Times?

Combustion blower creating sufficient draft (pressure)?

Replace pressure switch and re−check operation

Check Wiring for Continuity

Yes

Check for

Continuity on 5 AMP Fuse

Are 115 Volts Present on Transformer Primary

Replace Transformer

Yes

Replace Furnace Control Board

Check vent (flue) for problems

I.E. restriction, etc.

Repair or Replace Wiring

Replace Fuse and Re−Check Operation

Is adequate gas supply available at gas valve?

Replace gas valve

Yes

Does burner remain lit and igniter go OFF?

Is LED flashing a Diagnostic

Code?

Check flame sensor, flame current & line voltage polarity, & ground wire on manifold

NOTE: Door switch must be taped closed to perform these checks. Remove tape when finished. NOTE: A “Heartbeat” is defined as the diagnostics LED flashing continually from bright to dim.

Yes

Correct gas supply problems and re−check operation

Burner remains lit, but igniter also stays ON

YesYes

Replace Furnace Control Board

440 08 2011 00

Single Stage Multi Position Furnace

Continued from Page 38

Does indoor blower start after “ON” delay?

Yes

Place Thermostat in “OFF” Removing call for Operation

Yes

Does Indoor Blower Shut OFF After Heat Off Delay

Yes

Are 115 Volts Present at control “Heat” & Neutral terminals?

Check blower motor, capacitor, and/or wiring

Troubleshooting Chart #3

Replace Furnace Control Board

Yes

Is Indoor Blower “Hard Wired” for Continuous Fan Operation?

Replace Furnace

Control Board

Service Manual

Heating Cycle Operation Check

Proper system operation

Yes

440 08 2011 00

INDEX

Adjusting Heat Anticipator, 12

Adjusting Manifold Pressure, 6

Air Proving Switch, See Pressure Switch

Blower Assembly, Conditioned Air, 26

Blower Speeds, Changing, 27

Blower Speeds, Selecting, 26

Blower, Exhaust, 22

Burners, 9

Capacitors, 26

Checking Capacitors, 26

Checking Flame Current, 26

Checking Grounding and Polarity, 4

Exhaust Blower, 22

Flame Current, Checking, 26

Furnace Theory of Operation, 3

Furnace Control Board, 25

Gas Valve/Ignition Control, Honeywell VR8205S, 11

Ground, Electrical, 4

Heat Anticipators, 12

High Altitude Operation, 9

Interlock Switch, 5

Introduction, 1

Checking Input (Firing) Rate, 5

Checking Temperature Rise, 11

Circulating Air Blower Data, 29

Combustion Air/Vent Piping, 17−22

Combustion Blower. See Exhaust Blower

Control Wiring, 12

Diagnostics Code Section, 35

Drain Trap, Condensate, 23

Electrical Supply, 4

Kits, Twinning, 13

Limit Switches, 13

L P Pressure Switch, 10

Piping, Vent/Combustion Air, 17−22

Polarity, Line Voltage, 4

Pressure Switches, 14−15

Pressures, Approximate Operating, 14

INDEX

Roll Out Limit Switch, 14

Room Thermostat, 12

Sequence of Operation Chart, 24

Supply, Electrical, 4

Supply, Gas, 5

Switch, Blower Door Interlock, 5

Switch, Transition Pressure, 14

Switch, L.P. Gas Pressure, 10

Switch, Main Limit, 13

Switch, Pressure, 14, 15

Switch, Roll Out Limit, 14

Switches, Limit, 13

Technical Service Data , 31 − 33

Temperature Rise, 11

Thermostat, Room, 12

Transition Pressure Switch, 14

Troubleshooting Charts, 34−39

Troubleshooting Guide, 13

Twinning Kits, 13

Unit Identification, 3

Vent Termination, Concentric, 21

Vent Termination, Standard, 17−21

Vent/Combustion Air Piping, 17

Wiring Diagram, 30

Wiring, Control, 12

International comfort products N9MP1, N9MP2, H9MPD, C9MPD, T9MPD Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual