INSTALLATION INSTRUCTIONS A80US2V Warm Air Gas Furnace Upflow / Horizontal Left and Right Air Discharge This manual must be left with the homeowner for future reference. 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. CAUTION NOTICE As with any mechanical equipment, personal injury can result from contact with sharp sheet metal edges. Be careful when you handle this equipment.
A80US2V Unit Dimensions - inches (mm) 1. NOTE - 20C and 20D size units installed in upflow applications that require air volumes of 1800 cfm (850 L/s) or greater must have one of the following: 1. Single side return air with transition to accommodate 20 x 25 x 1in. (508 x 635 x 25 mm) cleanable air filter. (Required to maintain proper air velocity.) 2. Single side return air with optional RAB Return Air Base 3. Return Air from bottom and one side. 4. Return air from both sides. 5. Return air from bottom. 2.
EXPANDED VIEW HEAT EXCHANGER COMBUSTION AIR INDUCER COMBUSTION AIR INDUCER PRESSURE SWITCH ROLLOUT SWITCH GAS VALVE CABINET BURNER BOX CONTROL BOX (INCLUDES INTEGRATED CONTROL, AND TRANSFORMER) BURNER ACCESS PANEL BLOWER ACCESS PANEL BLOWER ASSEMBLY Figure 1 506891-01 Issue 1235 Page 3 of 65
A80US2V Gas Furnace The A80US2V gas furnace is shipped ready for installation in the upflow or horizontal position (left or right). The furnace is shipped with the bottom panel in place. The bottom panel must be removed if the unit is to be installed in a horizontal application. The panel may also be removed in upflow applications. The furnace is equipped for installation in natural gas applications. A conversion kit (ordered separately) is required for use in propane/LP gas applications.
Temperature Rise NOTE: Furnace must be adjusted to obtain a temperature rise (high and low fire) within the range(s) specified on the unit nameplate. Failure to do so may cause erratic limit operation and may result in premature heat exchanger failure. This furnace must be installed so that its electrical components are protected from water.
General These instructions are intended as a general guide and do not supersede local codes in any way. Consult authorities having jurisdiction before installation. In addition to the requirements outlined previously, the following general recommendations must be considered when installing one of these furnaces: • • • • Place the furnace as close to the center of the air distribution system as possible. The furnace should also be located close to the chimney or vent termination point.
All gas fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliances will operate inefficiently and unsafely. Enough air must be provided to meet the needs of all fuel burning appliances and appliances such as exhaust fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is necessary to ensure proper combustion and to prevent a downdraft.
When ducts are used, they shall be of the same cross sectional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be no less than 3 inches (75 mm). In calculating free area, the blocking effect of louvers, grilles, or screens must be considered.
Setting Equipment Upflow Applications Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or alcove installations are shown in Figure 8. WARNING Do not install the furnace on its front or its back. Do not connect the return air ducts to the back of the furnace. Doing so will adversely affect the operation of the safety control devices, which could result in personal injury or death.
Return Air - Upflow Applications Return air can be brought in through the bottom or either side of the furnace installed in an upflow application. If the furnace is installed on a platform with bottom return, make an airtight seal between the bottom of the furnace and the platform to ensure that the furnace operates properly and safely. The furnace is equipped with a removable bottom panel to facilitate installation.
Removing the Bottom Panel Remove the two screws that secure the bottom cap to the furnace. Pivot the bottom cap down to release the bottom panel. Once the bottom panel has been removed, reinstall the bottom cap. See Figure 11. Removing the Bottom Panel Horizontal Applications The furnace can be installed in horizontal applications. Order horizontal suspension kit (51W10) from Allied Air, or use equivalent suspension method. Allow for clearances to combustible materials as indicated on the unit nameplate.
Horizontal Application Unit installed on Platform Table 1 Duct System Use industry approved standards (such as those published by Air Conditioning Contractors of America or American Society of Heating, Refrigerating and Air Conditioning Engineers) to size and install the supply and return air duct system. This will result in a quiet and low static system that has uniform air distribution. Figure 14 NOTE: Do not operate the furnace in the heating mode with an external static pressure that exceeds 0.
Venting A 4 inch diameter flue transition is factory installed on the combustion air inducer outlet of all models. Figure 16 shows the combustion air inducer as shipped from the factory. Mounting Screws Location If necessary reposition the combustion air inducer, pressure switch and/or make-up box as needed per the following steps. See Figures 16 through 22. 1. Remove the four mounting screws (Figure 15) which secure the combustion air inducer / pressure switch assembly to the orifice plate.
Horizontal Position HORIZONTAL LEFT POSITION Top Vent discharge • • HORIZONTAL RIGHT POSITION Top Vent Discharge Disconnect pressure switch hose from barbed fitting on the pressure switch assembly. Remove pressure switch assembly (1 screw) and cut wire tie to free pressure switch wires. Reinstall pressure switch on the other side of orifice plate and reconnect pressure switch hose.
These series units are classified as fan assisted Category I furnaces when vertically vented according to the latest edition of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the USA. A fan assisted Category I furnace is an appliance equipped with an integral mechanical means to either draw or force combustion products through the combustion chamber and/or heat exchanger. This unit is not approved for use with horizontal venting. NOTE: Use these instructions as a guide. They do not supersede local codes.
Common Venting Using Tile Lined Interior Masonry Chimney and Combined Vent Connector NOTE: Refer to provided venting tables for installations. NOTE: The chimney must be properly sized per provided venting tables or lined with listed metal lining system. Figure 25 DO NOT insulate the space between the liner and the chimney wall with puffed mica or any other loose granular insulating material.
6. The entire length of single wall metal vent connector shall be readily accessible for inspection, cleaning, and replacement. 7. Single appliance venting configurations with zero lateral lengths (Tables 3 and 4) are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90° elbows.
Capacity of Type B Double Wall Vents with Type B Double Wall Connectors Serving a Single Category I Appliance NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.
Capacity of Type B Double Wall Vents with Single Wall Metal Connectors Serving a Single Category I Appliance NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90 ° elbows. For each additional 90° elbow or equivalent (for example two 45° elbows equal one 90° elbow) beyond two, the maximum capacity listed in the venting table should be reduced by 10 percent (0.
Vent Connector Capacity Type B Double Wall Vents with Type B Double Wall Connectors Serving Two or More Category I Appliances Table 5 Common Vent Capacity Type B Double Wall Vents with Type B Double Wall Connectors Serving Two or More Category I Appliances Table 6 Page 20 of 65 Issue 1235 506891-01
Vent Connector Capacity Type B Double Wall Vents with Single Wall Metal Connectors Serving Two or More Category I Appliances NOTE: Single appliance venting configurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent configurations, the vent system is assumed to have two 90 ° elbows.
Removal of the Furnace from Common Vent In the event that an existing furnace is removed from a venting system commonly run with separate gas appliances, the venting system is likely to be too large to properly vent the remaining attached appliances. Conduct the following test while each appliance is operating and the other appliances (which are not operating) remain connected to the common venting system.
Gas Piping CAUTION If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet. The flexible connector can then be added between the black iron pipe and the gas supply line. Gas Supply 1. This unit is shipped standard for left or right side installation of gas piping (or top entry in horizontal applications). Connect the gas supply to the piping assembly. 2.
NOTE: BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET Figure 26 Horizontal Applications Possible Gas Piping Configurations NOTE: BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET Figure 27 Page 24 of 65 Issue 1235 506891-01
Leak Check After gas piping is completed, carefully check all piping connections (factory and field installed) for gas leaks. Use a leak detecting solution or other preferred means. NOTE: If emergency shutoff is necessary, shut off the main manual gas valve and disconnect the main power to the furnace. The installer should properly label these devices. The unit is equipped with a field make-up box on the left hand side of the cabinet.
3. When there is a cooling demand, the indoor blower will run on the cooling speed designated by the positions of DIP switches (A, B, C, D) of the COOL jumper plug. Table 10 4. Before connecting the thermostat, check to make sure the wires will be long enough for servicing at a later date. Make sure that thermostat wire is long enough to facilitate future removal of blower for service. 5. Complete the wiring connections to the equipment.
Figure 31 506891-01 Issue 1235 Page 27 of 65
Optional Accessories for use with any ConfortSync® System Figure 32 Page 28 of 65 Issue 1235 506891-01
A80US2V Field Wiring Applications with Conventional Thermostat * Not required on all units.
A80US2V Field Wiring Applications with Conventional Thermostat (continued) * Not required on all units.
A80US2V Field Wiring Applications with Conventional Thermostat (continued) * Connect W1 to W1 ONLY if using defrost tempering kit 67M41 NOTE: Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the A80 integrated control.
A80US2V Field Wiring Applications with Conventional Thermostat (continued) * Connect W1 to W1 ONLY if using defrost tempering kit 67M41 NOTE: Do NOT make a wire connection between the room thermostat L terminal and the L terminal of the A80 integrated control.
A80US2V Schematic Wiring Diagram Figure 33 506891-01 Issue 1235 Page 33 of 65
Typical A80US2V Field Wiring Diagram Figure 34 Page 34 of 65 Issue 1235 506891-01
Integrated Control Figure 35 506891-01 Issue 1235 Page 35 of 65
Integrated Control DIP Switch Settings - Conventional Thermostat (non-communicating) A95US2V units are equipped with a two-stage, variable speed integrated control. This control manages ignition timing, heating mode fan off delays and indoor blower speeds based on selections made using the control dip switches and jumpers. The control includes an internal watchguard feature which automatically resets the ignition control when it has been locked out.
Ramping Option 0 • Motor runs at 100% until demand is satisfied. • Once demand is met, motor ramps down to stop. Cooling Mode Blower Speed Ramping R am p in g O p tio n A (F actory) B C D S w itch 9 O ff O ff On On S w itch 10 O ff On O ff On Table 15 Ramping Option A (Factory Selection) • Motor runs at 50% for 30 seconds. • Motor then runs at 82% for approximately 7-1/2 minutes. • If demand has not been satisfied after 7-1/2 minutes, motor runs at 100% until demand is satisfied.
On-Board Links NOTE: In systems with a conventional outdoor unit (noncommunicating), the on-board clippable links must be set to properly configure the system. On-Board Link W915 2 Stage Compr (Y1 to Y2) On-board link W915 is a clippable connection between terminals Y1 and Y2 on the integrated control. W915 must be cut if two-stage cooling will be used. If the Y1 to Y2 link is not cut the outdoor unit will operate in second-stage cooling only.
OPERATING SEQUENCE A80US2V, Non-Communicating Thermostat with Humidity Control Feature and Single-Speed Outdoor Unit O P E R A T IN G SYSTEM DEMAND SEQUENCE T herm ostat D em and S ystem S tep C ondition SYSTEM RESPONSE R elative H um idity W Y1 0 G On On 1 S tatus D B low er C om pressor CFM C om m ents (C O O L) N O C A LL FO R D E H U M ID IF IC A T IO N N orm al O peration 1 On A cceptable 24 VAC H igh 100% H igh 100% C om pressor and indoor blow er follow therm ostat dem an
OPERATING SEQUENCE A80US2V, Non-Communicating Thermostat with Humidity Control Feature and Two-Speed Outdoor Unit O P E R A T IN G SEQUENCE SYSTEM DEMAND T herm ostat D em and S ystem C ondition SYSTEM RESPONSE R elative H um idity S te p Y1 Y2 a G On On W W 1 2 B low er C om pressor CFM S tatus D On A cceptable 24 VAC Low 70% * On A cceptable 24 VAC H igh 100% 24 Low 70% * C om m ents (C O O L) N O C AL L F O R D E H U M ID IF IC ATIO N N orm al O pera tion - Y 1 1 On N
START-UP WARNING For Your Safety, Read Before Operating If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury, or loss of life. WARNING Do not use this furnace if any part has been under water. Immediately call a licensed professional service technician (or equivalent) to inspect the furnace and to replace any part of the control system and any gas control which has been under water. Gas Valve Operation (Figures 36 and 37) 1.
12. If the appliance will not operate, follow the instructions “Turning Off Gas to Unit” and call your service technician or gas supplier. Supply Line Pressure A threaded plug on the inlet side of the gas valve provides access to the supply pressure tap. Turning Off Gas to Unit 1. Set the thermostat to the lowest setting. 2. Turn off all electrical power to the unit if service is to be performed. 3. Remove the upper access panel. 4. Move gas valve switch to OFF position. Do not force. See Figure 36 or 37.
OPERATION High Altitude The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. See Table 23 through 26 for manifold pressures, pressure switch and gas conversion kits at all altitudes. WARNING For safety, shut unit OFF and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug. Manifold Pressure Settings This is the only permissible derate for these units.
OTHER UNIT ADJUSTMENTS Primary and Secondary Limits The primary limit is located on the heating compartment vestibule panel. The secondary limits (if equipped) are located in the blower compartment, attached to the back side of the blower. These auto reset limits are factory set and require no adjustment. Flame Rollout Switches (Two) These manually reset switches are located on (or inside of) the burner box. If tripped, check for adequate combustion air before resetting.
4. Application Using a Two Stage Thermostat B - Heating Sequence - Control Thermostat Selection DIP switch in “Variable Capacity” Position NOTE: In these applications, two-stage heat will be initiated by the integrated control if heating demand has not been satisfied after the field adjustable period (7 or 12 minutes). 1. On a call for heat, thermostat first stage contacts close sending a signal to the integrated control.
SERVICE Flue And Chimney 1. Check flue pipe, chimney and all connections for tightness and to make sure there is no blockage. 2. Check unit for proper draft. WARNING ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD. Electrical 1. Check all wiring for loose connections. 2. Check for the correct voltage at the furnace (furnace operating). Correct voltage is 120VAC ± 10%. 3. Check amp-draw on the blower motor with inner blower panel in place.
A80US2V Burner, Combustion Air Inducer Assembly & Heat Exchanger Removal Figure 40 9. Remove screws from both sides, top and bottom of vestibule panel. 10. Remove heat exchanger. It may be necessary to spread cabinet side to allow more room. If so, remove five screws from the left side or right side of cabinet. See Figure 42. 11. Back wash using steam. Begin from the burner opening on each clam. Steam must not exceed 275°F. 12.
A80US2V NOX Inserts 18. Reconnect all wires. 19. Reconnect top cap and vent pipe to combustion air inducer outlet. 20. Reconnect gas supply piping. 21. Turn on power and gas supply to unit. 22. Set thermostat and check for proper operation. 23. Check all piping connections, factory and field, for gas leaks. Use a leak detecting solution or other preferred means. CAUTION Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leat test has been completed.
Planned Service The following items should be checked during an annual inspecation. Power to the unit nmust be shut OFF for the service technician’s safety. Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) - Must be open and unobstructed to provide combustion air. Operating performance - Unit must be observed during operation to monitor proper performance of the unit and the vent system. Burners - Must be inspected for rust, dirt, or signs of water.
Integrated Control Diagnostic Modes D isplay N o chang e (idle)* S olid"E" S olid"D" S olid"F" S olid"P" ( variable spee d only) A ction (w hen button release d) R em ain in idle m od e E nter diagn ostic recall m ode D ischarge A ir Installed E nter flam e signal m ode P rogram unit capacity/size (U nit C ode)** * No change implies the display will continue to show whatever is currently being displayed for normal operation (blinking decimal, active error code, heat state, etc ..
Integrated Control Diagnostic Codes C ode E 105 D iagnostic C odes/S tatus of E quipm ent A ction R equired to C lear and R ecover D evice com m unication problem - N o other devices on R S B U S (C om m u nication system ). E 110 Low line voltage . E 1]1 Line voltage po larity reversed. E 112 G round not detected E 113 H igh line voltage. E 114 Line voltage frequency out-of-range. E 115 Low 24V - C ontrol w ill restart if the error recovers. E 116 H igh 24V .
Integrated Control Diagnostic Codes (continued) E 131 C orrupted control param eters (V erify configuration of system ). C om m unicating only. E 180 O utdoor air tem perature sensor failure. O nly show n if shorted or out-ofrange. E 200 H ard lockout - R ollout circuit open or previously open. E201 Indoor blow er com m unication failure - U nable to com m unicate w ith blow er m otor. E 202 Indoor blow er m otor m is-m atch - Indoor m otor horsepow er does not m atch unit capacity. S ee P age 67.
Integrated Control Diagnostic Codes (continued) C ode D iagnostic C odes/S tatus of E quipm ent A ction R equired to C lear and R ecover E 223 Low pressure sw itch failed open . E 224 Low pressure sw itch fa iled closed - R efer to troubleshooting . P age 68. E 225 H igh pressure sw itch failed open - R efer to troubleshooting . P age 68. E 226 H igh pressure sw itch failed closed - R efer to troubleshooting. P age 68. E 227 Low pressure sw itch open during trial for ignition o r run m ode.
Integrated Control Diagnostic Codes (continued) E 272 S oft lockout - E xceeded m axim um num ber of recycles. Last recycle due to the pressure sw itch opening. C heck operation of low pressure sw itch to see if it is stuck closed on heat call. C heck pressure (inches w .c.) of high pressure sw itch c losing on heat call. M easure operating pressure (inches w .c.). Inspect vent and com bustion air inducer for correct ope ration and restriction. C lears w hen heat call finishes successfully.
Integrated Control Diagnostic Codes (continued) C ode D iagnostic C odes/S tatus of E quipm ent A ction R equired to C lear and R ecover E 312 R estricted air flow in cooling or continuous fan m ode is low er than cfm setting. W arning O nly. R estricted airflow - Indoor blow er is running at a reduced C F M (C utback M ode - T he variable speed m otor has pre -set speed and torque lim iters to protect the m oto r from dam age caused by operating outs ide of design param eters (0 to 0.8 " W .C ..
Integrated Control Diagnostic Codes (continued) E406 LS O M - C om pressor open start circuit. R equired am ount of current is not passing through S tart current transform er. C lears the error after current is sensed in S T A R T sensor, or after pow er re set. E 407 LS O M - C om pressor open run circuit. R equired am ount of current is not passing through R un current transform er. C lears the error after current is sensed in R U N sensor, or 1 norm al com p ressor run cycle, or after pow er reset.
Program Unit Capacity / Size Mode 506891-01 Issue 1235 Page 57 of 65
Troubleshooting: Heating Sequence of Operation Page 58 of 65 Issue 1235 506891-01
Troubleshooting: Heat Sequence of Operation (continued) 506891-01 Issue 1235 Page 59 of 65
Troubleshooting: Heat Sequence of Operation (continued) Page 60 of 65 Issue 1235 506891-01
Troubleshooting: Heat Sequence of Operation (continued) 506891-01 Issue 1235 Page 61 of 65
Troubleshooting: Continuous Fan Sequence of Operation Page 62 of 65 Issue 1235 506891-01
START-UP & PERFORMANCE CHECK LIST UNIT SET UP 506891-01 Issue 1235 Page 63 of 65
UNIT OPERATION Page 64 of 65 Issue 1235 506891-01