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Allied 95G1UHEX Service Manual

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SERVICE MANUAL
95G1UHEX Gas Furnace
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.
95G1UHEX series units are high-efficiency gas furnaces
available in heating input capacities of 40,000 to 100,000
Btuh and cooling applications from 2 through 5 tons. Refer
to Engineering Handbook for proper sizing.
Units are factory equipped for use with natural gas. All
95G1UHEX units are equipped with a hot surface ignition
system. The gas valve is redundant to assure safety shut-
off as required by C.S.A.
The heat exchanger, burners and manifold assembly can
be removed for inspection and service. The maintenance
section gives a detailed description on how this is done.
All specifications are subject to change. Procedures
outlined in this manual are presented as a recommendation
only and do not supersede or replace local or state codes.
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 HVAC installer (or
equivalent), service agency or the gas supplier.
As with any mechanical equipment, contact with sharp
sheet metal edges can result in personal injury. Take
care while handling this equipment and wear gloves
and protective clothing.
508034-02
WARNING
CAUTION

Table of Contents

Technical Specifications ..............................................2
Blower Performance ....................................................3
Parts Arrangement.......................................................5
Unit Components .........................................................6
Placement and Installation ........................................15
Joint Cementing Procedure .......................................16
Venting Practices .......................................................16
Vent Piping Guidelines ..............................................17
Start-Up .....................................................................37
Heating System Service Checks ...............................38
Typical Operating Characteristics ..............................41
Maintenance ..............................................................42
Electric shock hazard.
Can cause injury or death. Before attempting
to perform any service or maintenance,
turn the electrical power to unit OFF at
disconnect switch(es). Unit may have
multiple power supplies.
*P508034-02*
Issue 2135
WARNING
(P) 508034-02
Page 1 of 49

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Summary of Contents for Allied 95G1UHEX

  • Page 1: Table Of Contents

    Unit Components ............6 Units are factory equipped for use with natural gas. All Placement and Installation ........15 95G1UHEX units are equipped with a hot surface ignition Joint Cementing Procedure ........16 system. The gas valve is redundant to assure safety shut- Venting Practices ............16...

  • Page 2: Technical Specifications

    Technical Specifications Physical and Electrical Data Max. Time Approx Nominal Volts/ Nominal Input Output AFUE Delay Trans Shipping Model Cooling Inlet Full Load (Btuh) (Btuh) (ICS) Breaker or (VA) Weight Capacity (in.) Phase Amps Fuse (lbs) 95G1UH040BE12X 40,000 39,000 3 Ton 120-60-1 95G1UH060BE12X 60,000...

  • Page 3: Blower Performance

    Blower Performance 95G1UH040BE12X Performance (Less Filter) Air Volume / Watts at Various Blower Speeds External Static High Medium-High Medium Medium-Low Pressure in. w.c. Watts Watts Watts Watts Watts 0.00 1450 1280 1190 0.10 1429 1268 1171 0.20 1400 1248 1139 0.30 1377 1222...
  • Page 4 95G1UH100CE20X Performance (Less Filter) Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air with Optional Return Air Single Side Return Air − Air volumes in bold require field fabricated External Base, Return Air from Both Sides or Return Air from Bottom and transition to accommodate 20 x 25 x 1 in.

  • Page 5: Parts Arrangement

    Parts Arrangement Exhaust Pipe Inlet Air Assembly Heat Exchanger Rollout Switch Burner Assembly Intake Air Pipe Gas Valve Combustion Gas Pipe Inlet Air Inducer (right side only) Ignition Control Ignition Control Figure 1. 508034-02 Issue 2135 Page 5 of 49...

  • Page 6: Unit Components

    A 24V circuit breaker is also located in the control box. The switch provides overcurrent protection to the transformer 95G1UHEX unit components are shown in Figure 1. The (T1). The breaker is rated at 3A at 32V. If the current...
  • Page 7 Pin # Function 1/4” Quick Connect Terminals Combustion Air Inducer Line 120HUM Humidifier 120VAC Ignitor Line LINE 120VAC Combustion Air Inducer Neutral XFMR Transformer 120VAC Ignitor Neutral CIRC Indoor blower 120VAC Table 1. 4-Pin Terminal Designation Indoor air quality accessory 120VAC NEUTRALS Common 120VAC Pin #...
  • Page 8 Red LED Flash Code Diagnostic Codes / Status of Furnace No power to control or board fault detected Board fault detected Heartbeat Control powered - displayed during all modes of operation if no errors are detected 1 flash Reverse line voltage polarity 2 flashes Improper earth ground 3 flashes...
  • Page 9 Electronic Ignition Cooling Fan On Time On a call for heat the integrated control monitors the The fan on time is 2 seconds and is not adjustable. combustion air inducer pressure switch. The control board will not begin the heating cycle if the pressure switch is Cooling Fan Off Time closed (by-passed).
  • Page 10 Test 1 Remove 5-pin plug from control Check ohms reading across terminals 1 and 5 Ohm value should be between 39 - 70. Meter (set to ohms) Integrated control detail Test 2 Seperate the 2-pin jack plug near the manifold and check resistance of the ignitor.
  • Page 11 Combustion Air Inducer (B6) & Cold End Header Box The 95G1UHEX uses an internally redundant valve to All 95G1UHEX units use a combustion air inducer to move assure safety shut-off. If the gas valve must be replaced, air through the burners and heat exchanger during heating the same type valve must be used.
  • Page 12 Each blower is statically and dynamically balanced as Shaft an assembly before installation in the unit. 95G1UHEX units are equipped with a constant torque ECM motor. It has a DC motor coupled to an electronic Figure 11. control module both contained in the same motor housing.
  • Page 13 1. Using an ohmmeter check the resistance from any one of the motor connector pins to the aluminum end TWO HARNESS plate of the motor. This resistance should be greater CONNECTIONS than 100k ohms. MOTOR Check the resistances between each of the three motor connector pins.
  • Page 14 Multi−Meter (set to VAC) Multi−Meter (set to VAC) Test 1 Test 3 (if necessary) Turn on power to unit. Check for 120 volts across terminals Check for 120 volts across terminals “CIRC” and “Neutrals” “L” and “N” on input plug P48. If voltage is present, continue on the integrated control.

  • Page 15: Placement And Installation

    Refer to IMPORTANT Table 9 for approved piping and fitting materials. 95G1UHEX exhaust and intake connections are made Schedule 40 PVC (Pipe) D1785 of PVC. Use PVC primer and solvent cement when...

  • Page 16: Joint Cementing Procedure

    Hammer blows should not be used when inserting pipe. If the 95G1UHEX furnace replaces a furnace that was After assembly, wipe excess cement from pipe at end commonly vented with another gas appliance, the size of of fitting socket.

  • Page 17: Vent Piping Guidelines

    Table 14. CAUTION The 95G1UHEX can be installed as either a Non-Direct Vent or a Direct Vent gas central furnace. The exhaust vent pipe operates under positive pressure and must be completely sealed to prevent leakage of NOTE: In Non-Direct Vent installations, combustion air is combustion products into the living space.
  • Page 18 Use the following steps to correctly size vent pipe diameter. different sizes of vent pipe, a combination vent pipe may be used. Contact Allied Air Technical Service for assistance in sizing vent pipe in these applications. NOTE: The exhaust collar on all models is sized to...
  • Page 19 STANDARD CONCENTRIC Wall Ring Wall Kit Flush- 1-1/2 in. 2 in. 3 in. Vent Pipe Mount Kit Input Dia. 2 in. 3 in. 2 in. Field Size (in.) Fabricated 51W11 (US) 22G44 (US) 44J40 (US) 71M80 (US) 69M29 (US) 60L46 (US) 15F74 51W12 (CA) 30G28 (CA)
  • Page 20 Maximum Allowable Intake or Exhaust Vent Length in Feet Standard Termination at Elevation 0 - 4500 ft 2" Pipe 3" Pipe Number of 90° Model Model Elbows Used Standard Termination at Elevation 4501 - 7500 ft 2" Pipe 3" Pipe Number of 90°...
  • Page 21 Maximum Allowable Intake or Exhaust Vent Length in Feet Concentric Termination at Elevation 0 - 4500 ft 2" Pipe 3" Pipe Number of 90° Model Model Elbows Used Concentric Termination at Elevation 4501 - 7500 ft 2" Pipe 3" Pipe Number of 90°...
  • Page 22 Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl Space For Intake Air in Feet Standard Termination at Elevation 0 - 4500 ft 2" Pipe 3" Pipe Number of 90° Model Model Elbows Used Standard Termination at Elevation 4501 - 7500 ft...
  • Page 23 EXHAUST EXHAUST INTAKE 2” 2” 2” 2” Appliance 3” Adaptor TRANSITION Appliance 2” Adaptor DO NOT transition *2” from smaller to larger 2” 3” pipe in horizontal runs *2” of exhaust pipe INTAKE TRANSITION * When transitioning up in pipe size, use the shortest length of 2” PVC pipe possible. Figure 23.
  • Page 24 Intake Piping INTAKE The 95G1UHEX furnace may be installed in either direct DEBRIS vent or non-direct vent applications. In non-direct vent SCREEN (Provided) applications, when intake air will be drawn into the furnace from the surrounding space, the indoor air quality must be considered and guidelines listed in Combustion, Dilution and Ventilation Air section must be followed.
  • Page 25 Roof Terminated (Minimum 12 in. Exhaust Pipe outdoors. The 95G1UHEX is then classified as a non- (305mm) above Attic Floor) direct vent, Category IV gas furnace. In Direct Vent applications, combustion air is taken...
  • Page 26 Maximum Allowable Exhaust Vent Pipe Length (in ft.) without Insulation in Unconditioned Space for Winter Design Temperatures Unit Input Size Winter Design Temperatures ºF Vent Pipe (ºC) Diameter 32 to 21 2 in. (0 to -6) 3 in. 2 in. 20 to 1 (-7 to -17) 3 in.
  • Page 27 ‡ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Allied Air recommends avoiding this location if possible. Figure 30. Vent Termination Clearances Direct Vent Installations...
  • Page 28 Details of Intake and Exhaust Piping Terminations for Direct Vent Installations 3” (76MM) MIN. SIZE PER EXHAUST PIPE Inches (MM) TERMINATION SIZE NOTE: In Direct Vent installations, combustion air is taken REDUCTION TABLE from outdoors and flue gases are discharged to outdoors. UNCONDITIONED ATTIC SPACE 8”...
  • Page 29 If intake and exhaust piping must be run up a side wall to position above snow accumulation or other EXHAUST obstructions, piping must be supported. At least one VENT bracket must be used within 6” from the top of the FLASHING 12”...
  • Page 30 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 31 ‡ Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Allied Air recommends avoiding this location if possible. Figure 40. Vent Termination Clearances...
  • Page 32 Details of Exhaust Piping Terminations for Non- SIZE PER EXHAUST PIPE Direct Vent Applications TERMINATION SIZE 12” (305MM) Exhaust pipes may be routed either horizontally through REDUCTION TABLE ABOVE AVE. an outside wall or vertically through the roof. In attic or SNOW ACCUMULATION closet installations, vertical termination through the roof...
  • Page 33 Condensate Piping NOTE: If necessary the condensate trap may be installed This unit is designed for either right- or left-side exit of up to 5’ away from the furnace. Use PVC pipe to connect trap to furnace condensate outlet. Piping from furnace condensate piping in upflow applications.
  • Page 34 line should be routed within the conditioned space to avoid freezing of condensate and blockage of drain line. If this is not possible, a heat cable kit may be used on the condensate trap and line. Heating cable kit is available in various lengths;...
  • Page 35 From Evaporator Coil IMPORTANT Field Provided Vent 1” min. 2” max. above When combining the furnace and evaporator coil condensate drain. drains together, the A/C condensate drain outlet must be vented to relieve pressure in order for the furnace pressure switch to operate properly. FurnaceCondensate Drain Connection Optional...
  • Page 36 Optional Condensate Drain Connection Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) 90° Street Elbow 3/4 inch PVC (not furnished) Adapter 3/4 inch slip X 3/4 inch mpt (not furnished) Condensate Drain Connection In Unit 1 (25 mm) Min. Vent 2 (50 mm) Max.

  • Page 37: Start-Up

    Remove the access panel. Move gas valve switch to OFF. See Figure 52. The gas valve on the 95G1UHEX is equipped with a gas Wait five minutes to clear out any gas. If you then control switch. Use only your hand to move the switch.

  • Page 38: Heating System Service Checks

    Use of a All units are C.S.A. design certified without modifications. specialty Gas Leak Detector is strongly recommended. It Refer to the 95G1UHEX Operation and Installation is available under part number 31B2001. Instruction Manual Information.
  • Page 39 Proper Combustion Furnace should operate at least 5 minutes before checking gas flow. Determine time in seconds for two revolutions of Furnace should operate minimum 15 minutes with correct gas through the meter. (Two revolutions assures a more manifold pressure and gas flow rate before checking accurate time.) Divide by two and compare to time in Table combustion.
  • Page 40 Proper Ground and Voltage as a function of load indicates a poor or partial ground. Compare the readings to Table 20. If the readings exceed the maximum shown, make repairs before WARNING operating the furnace. In addition, measure the AC voltage from Line Hot Electric Shock Hazard.

  • Page 41: Typical Operating Characteristics

    Temperature Rise Supply Duct Static Return Duct Static + Temperature rise for 95G1UHEX units depends on unit input, blower speed, blower horsepower and static pressure Total Duct Static = as marked on the unit rating plate. The blower speed must (dry coil) be set for unit operation within the range of “TEMP.

  • Page 42: Maintenance

    At the beginning of each heating season, and to comply operation. with the Allied Air Limited Warranty, your system should be checked as follows: 1. Check the operation of the ignition system, inspect and clean flame sensor.
  • Page 43 Winterizing and Condensate Trap Care Disconnect gas supply piping. Remove the screw securing the air fuel plenum and remove along with 1. Turn off power to the unit. the air inake assembly as one component. Have a shallow pan ready to empty condensate water. Remove screws from both sides, top and bottom of Remove the drain plug from the condensate trap and vestibule panel.
  • Page 44 Heat Exchanger Gaskets Burner Box Air Gas Plenum Burner Rollout Switch (location) Sensor Primary Limit Air Orifice Ignitor Gas Valve Gas Orifice Figure 58. Burner, CAI Assembly & Heat Exchanger Removal Page 44 of 49 Issue 2135 508034-02...

  • Page 45: Wiring Diagram And Sequence Of Operation

    Wiring Diagram and Sequence of Operation Line voltage is applied to L1 and N. the T1 low voltage transformer is energized, and line voltage is applied to B3 indoor blower. S47 rollout switch(es) must be closed in order for 24V from transformer to be output on integrated control ”R” to power thermostat. When there is a call for heat, W1 of the thermostat energizes W of the furnace control with 24VAC.
  • Page 46 Troubleshooting: Heating Sequence of Operation ABNORMAL HEATING MODE NORMAL HEATING MODE POWER ON GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER DELAY OFF. CONTROL SELF-CHECK OKAY? LED SLOW FLASH (RESET CONTROL BY TURNING MAIN POWER OFF.) LED FLASHES CODE 1 - POLARITY IS POLARITY CORRECT? REVERSED.
  • Page 47 Troubleshooting: Heating Sequence of Operation (Continued) NORMAL HEATING MODE ABNORMAL HEATING MODE 15 SECOND COMBUSTION AIR INDUCER PREPURGE INITIATED BY CLOSED PRESSURE SWITCH. LED FLASHES CODE 13 - LOW LINE VOLTAGE. ONCE VOLTAGE IS ABOVE IS VOLTAGE ABOVE 70 VOLTS? IGNITOR WARM UP -- 20 SECONDS.
  • Page 48 Troubleshooting: Cooling Sequence of Operation NORMAL COOLING MODE ABNORMAL COOLING MODE POWER ON IGNITION CONTROL MAIN POWER ON. LED FLASHES STEADY - CIRCUIT BOARD FAILURE CONTROL SELF DIAGNOSTIC CHECK. GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. IS CONTROL OPERATING NORMALLY? INDOOR BLOWER OFF WITH NORMAL DELAY.
  • Page 49 Troubleshooting: Continuous Fan / Accessories Sequence of Operation LED: SLOW FLASH RATE REMAINS UNCHANGED THROUGHOUT SEQUENCE. MANUAL FAN SELECTION MADE AT THERMOSTAT. CONTROL (G) ENERGIZES SYSTEM FAN AT FAN SPEED. EAC TERMINAL IS ENERGIZED. THERMOSTAT CALLS FOR HEAT (W). SYSTEM FAN CONTINUES FAN SPEED WITHOUT THERMOSTAT CALLS FOR COOLING.

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