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Lennox Allied Air Enterprise A97DSMV Installation Instructions Manual

Warm air gas furnace downflow air discharge direct vent
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INSTALLATION INSTRUCTIONS
A97DSMV
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to
the potential for personal injury or death.
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, personal
injury or loss of life. Installation and service must be
performed by a licensed professional installer (or
equivalent), service agency or the gas supplier.
A thermostat is not included and must be ordered
separately.
•
A Comfort Sync
communicating applications.
•
In non-communicating applications, a traditional
non-communication thermostat may be used.
In all cases, setup is critical to ensure proper system
operation.
Field wiring for both communicating and non-
communicating applications is illustrated in these
instructions.
Manufactured By
Allied Air Enterprises LLC
A Lennox International, Inc. Company
215 Metropolitan Drive
West Columbia, SC 29170
507029-05
This manual must be left with the homeowner for future reference.
WARNING
NOTICE
thermostat must be used in
®
Warm Air Gas Furnace
Downflow Air Discharge

Table of Contents

Unit Dimensions ............................................................2
Parts Arrangement.........................................................3
Gas Furnace ..................................................................4
Shipping and Packing List .............................................4
Safety Information .........................................................4
General ..........................................................................6
Installation .....................................................................6
Filters .............................................................................9
Duct System ..................................................................9
Venting.........................................................................13
Condensate Piping ......................................................25
Gas Piping ...................................................................28
Electrical ......................................................................30
Blower Performance ....................................................46
Unit Start-Up ................................................................50
Other Unit Adjustments ...............................................54
Heating Sequence of Operation .................................55
Service.........................................................................56
Repair Parts List ..........................................................58
Integrated Control Diagnostic Codes...........................58
As with any mechanical equipment, personal injury can
result from contact with sharp sheet metal edges. Be
careful when you handle this equipment.
*P507029-05*
Issue 2241
Direct Vent
CAUTION
(P) 507029-05
Page 1 of 73

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Summary of Contents for Lennox Allied Air Enterprise A97DSMV

  • Page 1: Table Of Contents

    Be careful when you handle this equipment. Manufactured By Allied Air Enterprises LLC *P507029-05* A Lennox International, Inc. Company 215 Metropolitan Drive (P) 507029-05 West Columbia, SC 29170 507029-05 Issue 2241...

  • Page 2: Unit Dimensions

    Unit Dimensions 9/16 (14) COMBUSTION Flue Condensate Trap Assembly AIR INTAKE Furnished for external RETURN AIR field installation (178) OPENING EXHAUST AIR on either side of unit. OUTLET (See installation instructions for additional information.) 2-1/16 (52) 9/16 2-1/4 (14) (57) (127) TOP VIEW 27-3/4...

  • Page 3: Parts Arrangement

    Parts Arrangement Blower Deck Blower Assembly Control Blower Access Cabinet Panel Burner Access Heat Exchanger Panel Assembly Combustion Primary Air Inducer Limit Gas Valve Burner Box and Manifold Assembly Figure 1. 507029-05 Issue 2241 Page 3 of 73...

  • Page 4: Gas Furnace

    Gas Furnace Safety Information The A97DSMV Category IV gas furnace is equipped with a variable capacity, variable speed integrated control. Each A97DSMV is shipped ready for installation in the downflow DANGER position. DANGER OF EXPLOSION! The furnace is equipped for installation in natural gas There are circumstances in which odorant used with applications only.
  • Page 5 For installation in a residential garage, the furnace must be NOTE: This furnace is designed for a minimum continuous installed so that the burner(s) and the ignition source are return air temperature of 60°F (16°C) or an intermittent located no less than 18 inches (457 mm) above the floor. operation down to 55°F (13°C) dry bulb for cases where a The furnace must be located or protected to avoid physical night setback thermostat is used.

  • Page 6: General

    Blower and vestibule access panels must be in place Installation on the furnace at all times. The furnace heat exchanger, components, duct Setting Equipment system, and evaporator coils must be thoroughly cleaned following final construction clean−up. Air filters must be replaced upon construction WARNING completion.
  • Page 7 Refer to Figure 2 for clearances in downflow applications. Units with 1/2 HP Blower Motor Figure 6. Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in Figure 7. * Front Back Sides...
  • Page 8 Figure 8. Figure 9. Lower supply air plenum into the combustible flooring Installation on Combustible Flooring base until plenum flanges seal against fiberglass When unit is installed on a combustible floor, a strips. downflow combustible flooring base must be installed between the furnace and the floor.

  • Page 9: Filters

    Return Air Opening - Downflow Units Duct System Return air may be brought in only through the top opening of a furnace installed in the downflow position. The following Use industry approved standards to size and install the steps should be taken when installing plenum: supply and return air duct system.
  • Page 10 Piping and Fittings Specifications CAUTION Schedule 40 PVC (Pipe) D1785 Solvent cements for plastic pipe are flammable liquids and should be kept away from all sources of ignition. Schedule 40 PVC (Fittings) D2466 Do not use excessive amounts of solvent cement when Schedule 40 CPVC (Pipe) F441 making joints.
  • Page 11 STANDARD CONCENTRIC Outdoor Outdoor Exhaust 1-1/2” 2” 3” Exhaust Flush Accelerator Concentric Concentric Concentric VENT Accelerator Mount Kit (Dia. X Length) Unit PIPE DIA. (Dia. X Length) (in.) 71M80 69M29 60L46 1-1/2” X 12” 2” X 12” 51W11 ** or 44W93+ +44W92++ +44W92++ 1-1/2...
  • Page 12 Remove inner blower door. 13. Install sheet metal screws (provided) to seal extra two holes in cabinet not used with side vent clamps. Remove access panels. Loosen hose clamps that attach rubber fittings to the Joint Cementing Procedure white PVC pipes inside the vestibule area. See Figure All cementing of joints should be done according to the specifications outlined in ASTM D2855.

  • Page 13: Venting

    Exhaust Piping Venting See Figure 19 and Figure 21 Route piping to outside of structure. Continue with Piping Suspension Guidelines installation following instructions given in piping termination section. CAUTION Do not discharge exhaust into an existing stack or stack that also serves another gas appliance. If vertical discharge through an existing unused stack is required, insert PVC pipe inside the stack until the end is even NOTE: Isolate piping at the point where it exits the outside wall or...
  • Page 14 Min. Equiv. Unit Example Vent Length 5 ft. plus 2 elbows of 1-1/2”,2”, 2-1/2” or 3” diameter pipe 070, 090, Furnace capacity? 5 ft. plus 2 elbows of 2”, 2-1/2 15 ft.* or 3” diameter pipe 5 ft. plus 2 elbows of 2-1/2” or 3”...
  • Page 15 Maximum Allowable Intake or Exhaust Vent Length (feet) Standard Termination at Elevation 0 - 4,500 ft 1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe Number of Model Model Model Model 90° Elbows Used Standard Termination at Elevation 4,501 - 10,000 ft 1-1/2”...
  • Page 16 Maximum Allowable Intake or Exhaust Vent Length (feet) Concentric Termination at Elevation 0 - 4,500 ft 1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe Number of Model Model Model Model 90° Elbows Used Concentric Termination Elevation 4,501 - 10,000 ft 1-1/2”...
  • Page 17 2” 2” 2” DO NOT transition from smaller to larger pipe size in horizontal runs of exhaust pipe. NOTE: 1-1/2” Vent Pipe Diameter Allowed Only on 070 Units 3” 1-1/2” TRANSITION TRANSITION Exhaust *2” *2” Air Intake TOP VIEW * When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible. NOTE −...
  • Page 18 Pipe Length 4” Maximum (Not Furnished) 3” 2” 2” TRANSITION *2” 2” Plate (Furnished) 90° Elbow (Not Furnished) TOP VIEW * When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible. NOTE Intake pipe and exhaust pipe must be the same diameter. Figure 21.
  • Page 19 VENT TERMINATION CLEARANCES FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA INSIDE CORNER DETAIL Fixed Operable Fixed Closed Closed Operable AREA WHERE TERMINAL AIR SUPPLY INLET VENT TERMINAL IS NOT PERMITTED US Installations Canadian Installations Clearance above grade, veranda, 12 inches (305mm) or 12 inches (305mm) 12 inches (305mm) or 12 inches (305mm) porch, deck or balcony...
  • Page 20 FIELD FABRICATED WALL TERMINATION NOTE − FIELD−PROVIDED REDUCER MAY BE 2” (51mm) 3” (76mm) REQUIRED TO ADAPT LARGER VENT PIPE SIZE Vent Pipe Vent Pipe TO TERMINATION A− Minimum clearance above grade or average 12” (305 mm) 12” (305 mm) snow accumulation B−...
  • Page 21 Maximum Allowable Vent Pipe Length without Insulation in Unconditioned Space for Winter Design Temperatures Modulating High Efficiency Furnace Winter Design Temperatures Vent Pipe Diameter ºF (ºC) 1-1/2 in. 2 in. 32 to 21 (0 to -6) 2-1/2 in. 3 in. 1-1/2 in.
  • Page 22 the intake pipe without a termination elbow is 8” and a minimum distance of 6” with a termination elbow. See Figure 24. If intake and exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, piping must be supported every 24”...
  • Page 23 Figure 28. Exiting Exhaust and Intake Vent 1 1/2” (38mm) accelerator provided on 71M80 & 44W92 EXHAUST Figure 31. Flush Mount Side Wall Termination kits for -045 and -070 models VENT 51W11 FLASHING 12” (305mm) INTAKE (Not Furnished) Minimum STRAIGHT-CUT OR Above Average ANGLE-CUT IN DIRECTION Snow...
  • Page 24 Exhaust through Crawl Space Vent Option All 33” condensing gas furnaces (92%+) are now approved Exhaust from Furnace to be vented down through a crawl space. Ensure a vent To Termination pipe drain kit, 51W18 (USA) or 15Z70 (Canada), is used as directed through the floor joists and into the crawl space.

  • Page 25: Condensate Piping

    If unit will be started immediately upon completion of Condensate Piping installation, prime trap per procedure outlined in Unit Start-Up section. This unit is designed for either right or left side exit of NOTE: Vinyl tubing may be used for condensate drain. condensate piping.
  • Page 26 IMPORTANT When combining the furnace and evaporator coil drains together, the A/C condensate drain outlet must be vented to relieve pressure in order for the furnace pressure switch to operate properly. Figure 40. Evaporator Coil Using a Common Drain CAUTION Do not use copper tubing or existing copper condensate lines for drain line.
  • Page 27 Optional Condensate Drain Connection Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) 90° Elbow 3/4 inch PVC (not furnished) Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.

  • Page 28: Gas Piping

    Leak Check Gas Piping After gas piping is completed, carefully check all field- installed piping connections for gas leaks. Use a commercially available leak detecting solution specifically manufactured for leak detection. Never use an open flame CAUTION to test for gas leaks. If a flexible gas connector is required or allowed by the The furnace must be isolated from the gas supply authority that has jurisdiction, black iron pipe shall be...
  • Page 29 Left Side Piping AUTOMATIC MANUAL (Standard) GAS VALVE MAIN SHUT-OFF MANUAL (with manual VALVE AUTOMATIC MAIN SHUT-OFF shut-off valve) (1/8 in. NPT GAS VALVE VALVE plugged tap (with manual (1/8 in. NPT shown) shut-off valve) plugged tap shown) GROUND JOINT UNION GROUND JOINT...

  • Page 30: Electrical

    Removal of the Furnace from Common Vent Electrical In the event that an existing furnace is removed from a venting system commonly run with separate gas ELECTROSTATIC DISCHARGE (ESD) appliances, the venting system is likely to properly vent the remaining attached appliances. Precautions and Procedures Conduct the following test while each appliance is operating and the other appliances (which are not operating) remain...
  • Page 31 Refer to Figure 46 for unit field wiring. See Figure 47 One 24V “H” terminal is provided on the furnace through Figure 55 for wiring of Comfort Sync thermostat integrated control terminal block. Any humidifier rated in communicating applications. Table 14 shows DIP up to 0.5 amp can be connected to this terminal with switch and onboard link settings for non-communicating the ground leg of the circuit being connected to either...
  • Page 32 Indoor Blower Speeds Generator Use - Voltage Requirements The following requirements must be kept in mind when NOTE: When this unit is used with a Comfort Sync specifying a generator for use with this equipment: thermostat, proper indoor blower speed selections are made by the communicating thermostat.
  • Page 33 Figure 46. A97DSMV Typical Field Wiring Diagram for Standard Non-Communicating Thermostat 507029-05 Issue 2241 Page 33 of 73...
  • Page 34 DATS (Optional) OATS (Optional) Communicating Communicating Outdoor Unit Indoor Unit Smart Hub Display Subbase Figure 47. Comfort Sync A3 with Communicating Indoor and Outdoor Units DATS (Optional) OATS (Optional) SETUP NOTES: CUT Y1-Y2 ON-BOARD MUNICATING) CUT R-O ON-BOARD LINK FOR OUTDOOR HEAT MUNICATING) Smart Hub Display...
  • Page 35 DATS (Optional) OATS (Optional) SETUP NOTE: CUT Y1-Y2 ON-BOARD LINK FOR 2-STAGE OUTDOOR UNITS (NON-COMMUNICATING) Smart Hub Display Subbase 24VAC Outdoor Unit Communicating (1 - or 2-Stage Indoor Unit Air Conditioner) Figure 49. Comfort Sync A3, Communicating Indoor Unit with 24VAC Air Conditioner Communicating Outdoor Unit If jumber is present between...
  • Page 36 Indoor Unit Controller Outdoor Unit Smart Hub HD Display Subbase 12VDC COM BUS ACC1 ACC2 R i+ I- C +12V -12V Single wire Single wire to indoor unit to bundle terminal “C”. wire to indoor Single wire terminal “C”. to terminal “C”. Unused wires Unused wires Unused wires...
  • Page 37 24VAC UV Light Applications: In any Allied communicating system, the indoor unit will FURNACE (IFC) OR AIR HANDLER (AHC) NOT have adequate power to to run the 24VAC UV light application. An additional transformer will be required. UV light wiring connections are independent of the HVAC system operation CHARGE AIR SENSOR (refer to UV light installation instruction.
  • Page 38 Communicating Indoor Unit HRV/ERV Terminal Block Smart Hub Display Subbase Wire Jumper required between ON and RED terminals. ACC1 is always low-stage for single- and two-stage ventilators. Figure 55. Comfort Sync A3 with Ventilation (Fresh Air Damper, ERV and HRV) Page 38 of 73 Issue 2241 507029-05...
  • Page 39 NEUTRAL TERMINALS COMBUSTION AIR INDUCER CONNECTOR IGNITOR CONNECTOR FLAME SENSE DIAGNOSTIC LINE VOLTAGE PUSH BUTTON TERMINALS DIP SWITCHES INDOOR BLOWER CONNECTOR OUTDOOR AIR SENSOR TERMINALS 7-SEGMENT DIAGNOSTIC LED W915 Y1 TO Y2 DISCHARGE AIR SENSOR W951 R TO O TERMINALS W914 R TO DS FACTORY TEST W915...
  • Page 40 DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections (Y1 to Y2) DIP Switch 1 (DS to R) (Oto R) Two-Stage Dehumidification Heat Pumps Cooling FURNACE OUTDOOR T'STAT TERM. STRIP UNIT 1 Heat / 1 Cool NOTE: Use DIP switch 3 to set Intact...
  • Page 41 DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections (Y1 to Y2) DIP Switch 1 (DS to R) (Oto R) Two-Stage Dehumidification Heat Pumps Cooling FURNACE OUTDOOR T'STAT TERM. STRIP UNIT 2 Heat / 2 Cool Intact Intact *Not required on all units FURNACE...
  • Page 42 DIP Switch Settings and On-Board Links W915 W914 W951 Thermostat Wiring Connections (Y1 to Y2) DIP Switch 1 (DS to R) (Oto R) Two-Stage Dehumidification Heat Pumps Cooling FURNACE HEAT PUMP TERM. STRIP T'STAT 67M41* Dual Fuel Single- Stage Heat Pump Thermostat w/dual Intact Intact...
  • Page 43 Operation Thermostat Switch 1 Switch 2 Switch 3 Variable Capacity Heat Two Stage (40% to 100%) 2nd stage delay OFF = 7 minutes Three Stage Heat ON = 12 minutes Single Stage (40%, 70%, 10%) 3rd stage delay 10 minutes fixed Two Stage Heat Single Stage (W1 70%, W2 100%)
  • Page 44 Ramping Option “C” Adjustment Switch 10 Switch 11 • Motor runs at 100% until demand is satisfied. + 10% • Once demand is met, motor runs at 100% for 45 NORMAL (Factory) seconds then ramps down to stop. - 10% (approx.) MOTOR TEST Table 18.
  • Page 45 On Board Links Field Test Mode On Board links must be clipped (when applicable) before Use the diagnostic push button to scroll through the menu unit is placed into operation with a non-communicating as described above. Release the button when the LED thermostat.

  • Page 46: Blower Performance

    Blower Performance A97DSMV070B12S BLOWER PERFORMANCE (less filter) HEATING BLOWER PERFORMANCE - 0 through 0.8 in. w.g. External Static Pressure Range Heating Input Range and Blower Volume - CFM Heating Adjust CFM Selections 100%. Increase (+15%) Heat CFM 1022 1118 Increase (+7.5%) Heat CFM 1041 Default Heat CFM Decrease (-7.5% ) Heat CFM...
  • Page 47 A97DSMV090C20S BLOWER PERFORMANCE (less filter) HEATING BLOWER PERFORMANCE Heating Input Range and Blower Volume - CFM Heating Adjust CFM Selections 100%. Increase (+15%) Heat CFM 1027 1176 1326 1475 1625 Increase (+7.5%) Heat CFM 1092 1232 1372 1512 Default Heat CFM 1009 1139 1269...
  • Page 48 Allowable Heating Speeds Model Number -15% -7.5% Default +7.5% +15% All Models Allowed Allowed Factory Setting Allowed Allowed Table 22. Allowable Circulation Speeds Model Number 38% of Second Stage Cooling All Models Factory Setting Table 23. Operating Sequence System Demand System Response Thermostat Relative Humidity...
  • Page 49 Operating Sequence System Demand System Response Thermostat Demand Relative Humidity Blower System Step Compressor Comments Condition (COOL) Status Stage Stage NO CALL FOR DEHUMIDIFICATION Normal Operation Acceptable Compressor and indoor - Y1 blower follow thermostat Normal Operation demand Acceptable High 100% - Y2 ROOM THERMOSTAT CALLS FOR FIRST STAGE COOLING...

  • Page 50: Unit Start-Up

    Adjust the thermostat to deactivate the heating demand Unit Start-Up and again wait for the combustion air inducer to stop. At this point, the trap should be primed with sufficient FOR YOUR SAFETY READ BEFORE OPERATING water to ensure proper condensate drain operation. BEFORE PLACING THE UNIT INTO OPERATION WARNING Smell all around the furnace area for gas.
  • Page 51 Move the gas valve switch to the OFF position. See NOTE: To obtain accurate reading, shut off all other gas Figure 57. appliances connected to meter. Wait five minutes to clear out any gas. If you then smell Gas Meter Clocking Chart gas, STOP! Leave the installation and Immediately Seconds for One Revolution call the gas supplier from a neighbor’s phone.
  • Page 52 Operating Pressure Signal High Altitude Information Operating pressure signal can be taken while the manifold NOTE: In Canada, certification for installation at elevations pressure check is taken (using two measuring devices). over 4500 feet (1372 m) is the jurisdiction of local Or, taken after the manifold pressure measurement is authorities.
  • Page 53 Gas Valve Field Installed Figure 58. Manifold Pressure Measurement Negative Port Positive Port Red and Black Tubing - Black Tubing + Gas Valve Field Installed Measuring Device Figure 59. Operation Signal (Delta P) Measurement 507029-05 Issue 2241 Page 53 of 73...

  • Page 54: Other Unit Adjustments

    Temperature Rise Other Unit Adjustments After the furnace has been started and supply and return air temperatures have been allowed to stabilize, check the temperature rise with the unit operating at 100 percent Primary Limit firing rate. If necessary, adjust the blower speed to maintain The primary limit is located on the heating compartment the temperature rise within the range shown on the unit vestibule panel.

  • Page 55: Heating Sequence Of Operation

    At the end of the recognition delay and on all Heating Sequence of Operation subsequent calls for heat in the same heating cycle, the integrated control energizes the combustion air The integrated control initiates a pressure switch inducer at high speed. The control also checks the high calibration at the initial unit start-up on a call for heat.

  • Page 56: Service

    If second-stage heat is required, the thermostat combustion air inducer at 70 percent speed. The second stage heat contacts close and send a signal indoor blower motor is adjusted to a speed which to the integrated control. The integrated control either matches the target rate.
  • Page 57 Filters Planned Service All filters are installed external to the unit. Filters should A service technician should check the following items be inspected monthly. Clean or replace the filters when during an annual inspection. Power to the unit must be necessary to ensure proper furnace operation.

  • Page 58: Repair Parts List

    Repair Parts List The following repair parts are available through Allied Air distributors. When ordering parts, include the complete furnace model number listed on the nameplate. All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier. Cabinet Parts Heating Parts •...
  • Page 59 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E105 Device communication problem - No other devices Equipment is unable to communicate. Indicates on RS BUS (Communication system). numerous message errors. In most cases, errors are related to electrical noise.
  • Page 60 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E180 Outdoor air temperature sensor failure. Only shown Compare outdoor sensor resistance to temperature if shorted or out of range (Communicating systems resistance charts in unit installation instructions. only) Replace sensor pack if necessary.
  • Page 61 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E225 High pressure switch failed open -Refer to Check pressure(inches W.C) of high pressure switch troubleshooting closing on heat call. Measure operating pressure (inches w.c. Inspect vent and combustion air inducer for correct operation and restriction Resumes normal operation after fault is cleared.
  • Page 62 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E273 Soft lockout - Exceeded maximum number of Check micro-amperes of flame sensor using control recycles. Last recycle due to flame failure diagnostics or field installed mode. Clean or replace sensor.
  • Page 63 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E312 Restricted airflow in cooling or continuous fan mode Warning Only. Restricted airflow - Indoor blower is is lower than CFM setting. running at a reduced CFM (Cutback Mode - The variable speed motor has pre-set speed and torque limiters to protect the motor from damage caused by operating outside of design parameters (0 to 0.8"...
  • Page 64 Code Diagnostic Codes / Status of Equipment Action Required to Clear and Recover E409 LSOM - Compressor low voltage. Secondary voltage is below 18VAC. After 10 minutes, operation is discontinued. Clears the code after voltage is higher than 20VAC for 2 seconds or after power reset.
  • Page 65 Program Unit Capacity / Size Mode Power-Up - Number displayed by integrated control represents unit size code (furnace model and capacity). If three horizontal bars are displayed followed by continuous E203, furnace control does not recognize unit size code. Configure per the following: Turn room thermostat to OFF.
  • Page 66 Troubleshooting: Heating Sequence of Operation IGNITION AND CALL FOR LOW FIRE WITH TWO-STAGE THERMOSTAT Safety Check Verify There Is No Main Burner Flame After Indoor blower OFF Heat OFF Delay (Low Heat Speed) Limit Combustion Air Limit Indoor Blower De-Energize Error Code Inducer On Switch...
  • Page 67 Troubleshooting: Heating Sequence of Operation (continued) CALL FOR HIGH FIRE WITH TWO-STAGE THERMOSTAT 2 Stage Thermostat 1st Call for High Fire? 2nd Stage Recognition Delay (30 Seconds) Combustion Air Inducer ON (100% Rate Speed) High Pressure Switch Increase Combustion Error Code Wait 5 Closes Within Air Inducer Speed...
  • Page 68 Troubleshooting: Heating Sequence of Operation (continued) RUN MODE (TWO-STAGE THERMOSTAT) RUN MODE (SINGLE-STAGE THERMOSTAT) FIRST OR SECOND-STAGE CALL FOR HEAT ALL INPUTS MONITORED (LIMIT, PRESSURE, ALL INPUTS MONITORED (LIMIT, PRESSURE, CALL FOR HEAT/COOL, FLAME LEVEL). CALL FOR HEAT/COOL, FLAME LEVEL). 2nd Stage Heat 2nd Stage Call for Heat...
  • Page 69 Troubleshooting: Heating Sequence of Operation (continued) IGNITION AND CALL FOR HEAT WITH SINGLE-STAGE THERMOSTAT Safety Check Verify There Is No Main Burner Indoor Blower OFF After Flame Heat OFF Delay (Low Heat Speed) Indoor Blower Limit Limit De-Energize Combustion Air Error Code Switch Closes Within 3...
  • Page 70 Troubleshooting: Cooling Sequence of Operation CALL FOR COOLING 1st Stage Cooling Request Received Energize 1st Stage Cooling Contactor (Compressor & Fan) Indoor Blower On After 2-second delay Energize Indoor Blower (Per Ramping Profile) 1st Stage 2nd Stage Cooling Request Cooling Still Active? Request? Energize 2nd Stage...
  • Page 71 Troubleshooting: Continuous Fan Sequence of Operation CONTINUOUS LOW SPEED INDOOR BLOWER SEQUENCE OF OPERATION Call for Continuous Blower Indoor Blower On (Speed Determined by Dip Switch settings) Request Maintain Indoor for Cooling Go to Call for Cooling Blower at set speed Received? Go to Call for Heat -- Two-Stage Thermostat Request...
  • Page 72 Requirements for Commonwealth of Massachusetts Modifications to NFPA-54, Chapter 10 INSPECTION. The state or local gas inspector of the side wall, horizontally vented, gas-fueled equipment Revise NFPA-54 section 10.8.3 to add the following shall not approve the installation unless, upon requirements: inspection, the inspector observes carbon monoxide For all side wall, horizontally vented, gas-fueled equipment...
  • Page 73 For the Province of Ontario, Horizontal Sidewall Vent Applications Only For exterior horizontal venting applications, the 2” X 1.5” reducer for 2” venting at the point where the exhaust pipe exits the structure is not required in direct or nondirect vent applications in the Province of Ontario. In these applications, the vent should be oriented such that the exhaust plume is unobjectionable.

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