INSTALLATION INSTRUCTIONS SL280UHV 2011 Lennox Industries Inc. Dallas, Texas, USA DAVE LENNOX SIGNATURE® COLLECTION GAS FURNACE UPFLOW / HORIZONTAL AIR DISCHARGE 506763−01 06/2011 Supersedes 03/2011 Litho U.S.A. THIS MANUAL MUST BE LEFT WITH THE HOMEOWNER FOR FUTURE REFERENCE This 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.
Unit Dimensions − inches (mm) 1NOTE − 60C and 60D units that require air volumes over 1800 cfm (850 L/s) must have one of the following: 1. Return air from single side transition will accommodate 20 x 25 x1 in. (508 x 635 x 25) cleanable air filter. (Required to maintain proper air D velocity) 2. Single side return air with optional RAB Return Air Base. 3. Return air from bottom and one side. FLUE OUTLET 4. Return air from both sides. (Top) 5. Return air from bottom.
Parts Arrangement HEAT EXCHANGER COMBUSTION AIR INDUCER COMBUSTION AIR INDUCER PRESSURE SWITCH ROLLOUT SWITCH GAS VALVE CABINET BURNER BOX INNER BLOWER ACCESS PANEL SIGHT GLASS CONTROL BOX (Includes two−stage integrated control, transformer and circuit breaker) ACCESS PANEL BLOWER ASSEMBLY FIGURE 1 Page 3
SL280UHV Gas Furnace WARNING The SL280UHV gas furnace is equipped with a two−stage, variable speed integrated control. the control is compatible with: Communicating thermostats − icomfort Touch®. Non−comunicating thermostats − ComfortSense or other conventional thermostats. Control systems − Harmony III Zone Control System (non−communicating). Each SL280UHV unit is shipped ready for installation in the upflow or horizontal position (left or right). The furnace is shipped with the bottom panel in place.
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 SL280UHV furnace must be installed so that its electrical components are protected from water.
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. Do not install the furnace where drafts might blow directly into it. This could cause improper combustion and unsafe operation. Do not block the furnace combustion air openings with clothing, boxes, doors, etc. Air is needed for proper combustion and safe unit operation.
Unconfined Space An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This space also includes adjacent rooms which are not separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by infiltration.
EQUIPMENT IN CONFINED SPACE ALL AIR FROM OUTSIDE (Inlet Air from Crawlspace and Outlet Air to Ventilated Attic) CHIMNEY OR GAS VENT VENTILATION LOUVERS (Each end of attic) OUTLET AIR FURNACE WATER HEATER INLET AIR VENTILATION LOUVERS (For unheated crawl space) AIR FLOW NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645 mm2) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure.
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 7. Setting Equipment 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 Single Side Return Air (with transition and filter) 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 10. Removing the Bottom Panel Horizontal Applications The SL280UHV furnace can be installed in horizontal applications. Order kit number 51W10 (or use equivalent) from Lennox. Allow for clearances to combustible materials as indicated on the unit nameplate.
TABLE 1 Horizontal Application Unit Installed on Platform Furnace Cabinet Width Line contact is permissible See the unit nameplate for clearances.
Venting A 4−inch diameter flue transition is factory-installed on the combustion air inducer outlet of all models. Figure 15 shows the combustion air inducer as shipped from the factory. Mounting Screws Location mounting screws 1 − Remove the four mounting screws (figure 14) which secure the combustion air inducer / pressure switch assembly to the orifice plate.
Horizontal Position HORIZONTAL RIGHT POSITION HORIZONTAL LEFT POSITION Top Vent Discharge Top Vent Discharge vent pipe vent pipe pressure switch pressure switch flue transition cover plate flue transition AIR AIR FLOW FLOW collector box cover plate make−up box collector box 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.
The SL280UHV 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. The SL280UHV is not approved for use with horizontal venting.. NOTE − Use these instructions as a guide.
Common Venting Using Tile−Lined Interior Masonry Chimney and Combined Vent Connector MINIMUM LENGTH = AS SHORT AS PRACTICAL. FOR MAXIMUM LENGTH SEE NOTE TO LEFT INTERIOR TILE−LINED MASONRY CHIMNEY 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.
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.
TABLE 3 Capacity of Type B Double−Wall Vents with Type B Double−Wall Connectors Serving a Single Category I Appliance Vent and Connector Diameter − D (inches) Height H (feet) 6 8 10 15 20 30 Lateral L (feet) 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MIN MAX 0 0 78 0 152 0 251 0 375 2 13 51 18 97 27 157 32 232 4 21 49 30 94 39 153 50 227 6 25 46 36 91 47 149 59 223 0 0 84 0 165 0 276 0
TABLE 4 Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors Serving a Single Category I Appliance Vent and Connector Diameter − D (inches) Height H (feet) 6 8 10 15 20 30 Lateral L (feet) 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MIN MAX 0 38 77 59 151 85 249 126 373 2 39 51 60 96 85 156 123 231 4 NR NR 74 92 102 152 146 225 6 NR NR 83 89 114 147 163 220 0 37 83 58 164
TABLE 5 Vent Connector Capacity Type B Double−Wall Vents with Type B Double−Wall Connectors Serving Two or More Category I Appliances Vent Height H (feet) 6 8 10 15 20 30 Vent and Connector Diameter − D (inches) Connector Rise R (feet) 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MIN MAX 1 22 37 35 66 46 106 58 164 2 23 41 37 75 48 121 60 183 3 24 44 38 81 49 132 62 199 1 22 40 35 72 49 114 64
TABLE 7 Vent Connector Capacity Type B Double−Wall Vents with Single−Wall Metal Connectors Serving Two or More Category I Appliances Vent and Connector Diameter − D (inches) Height H (feet) 6 8 10 15 20 30 Lateral L (feet) 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MIN 1 NR NR NR NR NR NR NR MAX NR 2 NR NR NR NR NR NR 168 182 3 NR NR NR NR 121 131 175 198 1 NR NR NR NR NR NA NR NR 2 NR NR N
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.
Left Side Piping (Standard) MANUAL MAIN SHUT−OFF VALVE (With 1/8 in. NPT Plugged Tap Shown) MANUAL MAIN SHUT−OFF VALVE (With 1/8 in.
Refer to figure 33 for unit field wiring. See figures 30 and 31 for icomfort Touch® thermostat wiring in communicating applications. Table 11 shows DIP switch and on−board link settings for non−communicating thermostat applications. Typical wiring schematic is shown in figure 32. Electrical ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures CAUTION Electrostatic discharge can affect electronic components.
8 − An unpowered, normally open (dry) set of contacts with a 1/4" spade terminal HUM" are provided for humidifier connections and may be connected to 24V or 120V. Any humidifier rated up to one amp can be connected to these terminals. In 120V humidifier applications the neutral leg of the circuit can be connected to one of the provided neutral terminals. This terminal is energized in the heating mode. 9 − Install the room thermostat according to the instructions provided with the thermostat.
icomfort Touch® Thermostat with SL280UHV and Non−Communicating Outdoor Unit icomfort Touch® Thermostat with SL280UHV and icomfort −ENABLED Outdoor Unit icomfort Touch® Thermostat icomfort −Enabled SL280UHV Indoor Furnace Non−Communicating Outdoor Air Conditioner OPTIONAL DISCHARGE AIR SENSOR icomfort Touch® THERMOSTAT icomfort Touch® Thermostat icomfort −Enabled SL280UHV Indoor Furnace icomfort −Enabled Outdoor Air Conditioner or Heat Pump icomfort − ENABLED SL280UHV FURNACE icomfort − ENABLED SL280U
Optional Accessories for use with any icomfort Touch® System NOTE: icomfort Touch® THERMOSTAT SENSES HUMIDITY & CONTROLS HUM CONTACTS TO CYCLE HUMIDIFIER BASED ON DEMAND. NO OTHER CONTROL OR HUMIDISTAT REQUIRED. 120V CONNECTIONS HUM" CONTACT IS CLOSED ANYTIME HUMIDITY DEMAND IS PRESENT OPTIONAL OUTDOOR AIR SENSOR FOR USE WITH HUMIDIFIER (IF NOT ALREADY IN THE SYSTEM FOR OTHER FUNCTIONS. BUILT INTO ALL icomfort by Lennox OUTDOOR UNITS).
TABLE 11 SL280 Field Wiring Applications With Conventional Thermostat DIP Switch Settings and On−Board Links (See figure 34) Thermostat DIP Switch 1 Thermostat Heating Stages 1 Heat / 1 Cool NOTE − Use DIP switch 2 to set second−stage heat ON delay. OFF−7 minutes. ON−12 minutes. ON 1 Heat / 2 Cool NOTE − Use DIP switch 2 to set second−stage heat ON delay. OFF−7 minutes. ON−12 minutes. ON 1 Heat / 2 Cool with t’stat with humidity control NOTE − Use DIP switch 2 to set second−stage heat ON delay.
TABLE 11 SL280 Field Wiring Applications With Conventional Thermostat (Continued) DIP Switch Settings and On−Board Links (See figure 34) Thermostat DIP Switch 1 Thermostat Heating Stages 2 Heat / 2 Cool On Board Links Must Be Cut To Select System Options OFF Wiring Connections S1 T’STAT CUT ON−BOARD LINK W915 2 STAGE COMPR FURNACE TERM. STRIP OUTDOOR UNIT * 2 Heat / 2 Cool with t’stat with humidity control OFF S1 T’STAT CUT ON−BOARD LINK W915 2 STAGE COMPR FURNACE OUTDOOR TERM.
TABLE 11 SL280 Field Wiring Applications With Conventional Thermostat (Continued) Thermostat Dual Fuel Single Stage Heat Pump DIP Switch Settings and On−Board Links (figure 34) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat System Options Heating Stages L7724U T’STAT OFF CUT ON−BOARD LINK W951 HEAT PUMP ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control Wiring Connections FURNACE TERM.
TABLE 11 SL280 Field Wiring Applications With Conventional Thermostat (Continued) Thermostat Dual Fuel Single Stage Heat Pump DIP Switch Settings and On−Board Links (figure 34) DIP Switch 1 On Board Links Must Be Cut To Select Thermostat System Options Heating Stages L7724U T’STAT OFF ComfortSense 7000 L7724U thermostat w/ dual fuel capabilities Capable of 2 stage gas heat control w/dehumidification control Wiring Connections CUT ON−BOARD LINK W951 HEAT PUMP H CUT ON−BOARD LINK W914 DEHUM OR HARMON
SL280UHV Schematic Wiring Diagram FIGURE 32 Page 33
TYPICAL SL280UHV FIELD WIRING DIAGRAM FIELD INSTALLED CLASS II 24V FIELD INSTALLED LINE VOLTAGE FIGURE 33 Page 34
Integrated Control ACC HUM HS/ CAI LINE 1 NEUTRAL 7 SEGMENT LED FLAME SENSE INDOOR BLOWER CONNECTOR DIAGNOSTIC PUSH BUTTON DIP SWITCHES 12 PIN LOW VOLTAGE CONNECTOR OUTDOOR AIR SENSOR TERMINALS DISCHARGE AIR SENSOR TERMINALS W915 Y1 TO Y2 2 STAGE COMPR W951 R TO O HEAT PUMP TB83 COMMUNICATING OUTDOOR EQUIPMENT TB84 COMMUNICATING INDOOR THERMOSTAT R I+ I−C R I+ I−C W1 W2 G Y2 Y1 C C R DH L O DS W914 R TO DS DEHUM OR HARMONY NON−COMMUNICATINGNG 24V TERMINALS RS−BUS LINK (TB82, future use) THER
Integrated Control DIP Switch Settings − Conventional Thermostat (non−communicating) SL280UHV 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.
TABLE 15 Cooling Mode Blower Speed Ramping Switch 9 Switch 10 Ramping Option A (Factory) Off Off B Off On C On Off D On On Ramping Option D Motor runs at 100% until demand is satisfied. 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. Once demand is met, motor runs at 50% for 30 seconds then ramps down to stop.
On−Board Links Note: In icomfort systems with a conventional outdoor unit (non−communicating), the on−board clippable links must be set to properly configure the system. WARNING Carefully review all configuration information provided. Failure to properly set DIP switches, jumpers and on−board links can result in improper operation! On−Board Link W914 Dehum or Harmony (R to DS) On−board link W914, is a clippable connection between terminals R and DS on the integrated control.
BLOWER DATA SL280UH070V36A BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH090V36B BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH090V48B BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH090V48B BLOWER PERFORMANCE (less filter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH090V60C BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH090V60C BLOWER PERFORMANCE (less filter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH110V60C BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH110V60C BLOWER PERFORMANCE (less filter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH135V60D BLOWER PERFORMANCE (less filter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTTOM AND ONE SIDE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
BLOWER DATA SL280UH135V60D BLOWER PERFORMANCE (less filter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w.g. (Heating) and 0 through 1.0 in. w.g.
TABLE 18 OPERATING SEQUENCE SL280UHV, Non−Communicating Thermostat with Humidity Control Feature and Single−Speed Outdoor Unit OPERATING SEQUENCE SYSTEM DEMAND Thermostat Demand System Condition Step Y1 O G W 1 SYSTEM RESPONSE Relative Humidity Compressor Blower CFM (COOL) Status D Acceptable 24 VAC High 100% Comments NO CALL FOR DEHUMIDIFICATION Normal Operation 1 On On On Compressor and indoor blower follow thermostat demand BASIC MODE (only active on a Y1 thermostat demand) Normal
TABLE 19 OPERATING SEQUENCE SL280UHV, Non−Communicating Thermostat with Humidity Control Feature and Two−Speed Outdoor Unit OPERATING SEQUENCE SYSTEM DEMAND Thermostat Demand System Condition Ste p Y1 Y2 O G W 1 SYSTEM RESPONSE Relative Humidity W 2 Status D Compressor Blower CFM (COOL) Comments NO CALL FOR DEHUMIDIFICATION Normal Operation − Y1 1 On On On Acceptable 24 VAC Low 70%* Normal Operation − Y2 2 On On On On Acceptable 24 VAC High 100% Compressor and indoor blower
2 − Set the thermostat to the lowest setting. Unit Start−Up FOR YOUR SAFETY READ BEFORE LIGHTING WARNING Do not use this furnace if any part has been underwater. 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. WARNING 3 − Turn off all electrical power to the unit. 4 − This furnace is equipped with an ignition device which automatically lights the burners.
TABLE 20 GAS METER CLOCKING CHART Seconds for One Revolution Natural LP SL280 Unit 1 cu ft 2 cu ft 1 cu ft 2 cu ft Dial Dial Dial DIAL −045 80 160 200 400 −70 55 110 136 272 −90 41 82 102 204 −110 33 66 82 164 −135 27 54 68 136 12− If the appliance will not operate, follow the instructions Turning Off Gas to Unit" and call your service technician or gas supplier. Turning Off Gas to Unit 1 − Set the thermostat to the lowest setting.
High Altitude The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. Tables 22 through 25 shows manifold pressure, pressures switch and gas conversion kits at all altitudes. IMPORTANT For safety, shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug. TABLE 22 Manifold Pressure Settings Unit Input 070 090 110 135 1 This Orifice Size 0 − 7500 ft.
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 − After the 20−second warm−up period has ended, the gas valve is energized on low fire (first stage) and ignition occurs. At the same time, the control module sends a signal to begin an indoor blower 30−second ON−delay. When the delay ends, the indoor blower motor is energized on the low fire heating speed and the HUM contacts are energized. The integrated control also initiates a second−stage on delay (factory−set at 7 minutes; adjustable to 12 minutes).
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. Electrical Service WARNING ELECTRICAL SHOCK, FIRE, OR EXPLOSION HAZARD. Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage. Improper servicing could result in dangerous operation, serious injury, death, or property damage. Before servicing, disconnect all electrical power to furnace.
SL280UHV BURNER, COMBUSTION AIR INDUCER ASSEMBLY & HEAT EXCHANGER REMOVAL gasket pressure switch rollout switch flue transition burner box assembly ignitor collector box heat exchanger orifice plate sensor combustion air inducer gasket burners manifold and gas valve retention rings burner box cover plate cross over FIGURE 39 13− To clean the combustion air inducer visually inspect and 9 − Remove screws from both sides, top and bottom of using a wire brush clean where necessary.
SL280UHV 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.
Planned Service The following items should be checked during an annual inspection. Power to the unit must 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 Display Action (when button released) No change (idle)* Remain in idle mode Solid E" Enter diagnostic recall mode Solid D" Discharge Air Installed Solid F" Enter flame signal mode Solid P" (variable speed only) Program unit capacity/size (Unit Code)** * 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 (continued) Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 105 Device communication problem − No other devices on RS BUS (Communication system). Equipment is unable to communicate. Indicates numerous message errors. In most cases errors are related to electrical noise. Make sure high voltage power is separated from RSBus. Check for mis− wired and/or loose connections between the stat, indoor unit and outdoor unit.
Integrated Control Diagnostic Codes (continued) E 131 Corrupted control parameters (Verify configuration of system). Communicating only. Reconfigure the system. Replace control if heating or cooling is not available. Only applicable in the communicating mode, not in startup. Exit from Commissioning and Execute ’Set Factory Default mode’. Control will still operate on default parameter settings. E 180 Outdoor air temperature sensor failure. Only shown if shorted or out−of− range.
Integrated Control Diagnostic Codes (continued) Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 223 Low pressure switch failed open. Check pressure (inches w.c.) of low pressure switch 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 E 224 Low pressure switch failed closed − Refer to troubleshooting. See Page 68.
Integrated Control Diagnostic Codes (continued) E 272 Soft lockout − Exceeded maximum number of recycles. Last recycle due to the pressure switch opening. Check operation of low pressure switch to see if it is stuck closed on heat call. Check pressure (inches w.c.) of high pressure switch closing on heat call. Measure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct operation and restriction. Clears when heat call finishes successfully.
Integrated Control Diagnostic Codes (continued) Code Diagnostic Codes/Status of Equipment Action Required to Clear and Recover E 312 Restricted air flow in cooling or continuous fan mode is lower than cfm setting. Warning Only. Restricted airflow − Indoor blower is 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" W.C.. total external static pressure).
Integrated Control Diagnostic Codes (continued) E 406 LSOM − Compressor open start circuit. Required amount of current is not passing through Start current transformer. Clears the error after current is sensed in START sensor, or after power reset. E 407 LSOM − Compressor open run circuit. Required amount of current is not passing through Run current transformer. Clears the error after current is sensed in RUN sensor, or 1 normal compressor run cycle, or after power reset.
Program Unit Capacity/Size Mode − − − Power−Up − Number displayed represents by integrated control 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: Furnace control in IDLE mode No heating, cooling or indoor fan operation) Yes To enter Program Unit Capacity/Size: push and hold button next to 7−segment LED display until solid P" symbol appears. Release button.
Troubleshooting: Heating Sequence of Operation CALL FOR FIRST−STAGE HEAT 1 CALL FOR 1ST STAGE HEAT (LOW FIRE) NO INDOOR BLOWER OFF AFTER HEAT FAN OFF DELAY (LOW HEAT SPEED) HIGH LIMIT SWITCH CLOSED? NO ERROR CODE FLASHES YES LIMIT SWITCH CLOSED WITHIN 3 MINUTES? INDOOR BLOWER ON(LOW HEAT SPEED) NO INDOOR BLOWER OFF AFTER HEAT FAN OFF DELAY (LOW HEAT SPEED) WATCHGUARD − ERROR CODE 1 FLASHES NO YES ROLLOUT CIRCUITS CLOSED? NO DE−ENERGIZE GAS VALVE YES LOW PRESSURE SWITCH OPEN? NO INDUCER ON
Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR SECOND−STAGE HEAT 2 CALL FOR 2ND STAGE HEAT 1 (HIGH FIRE) SINGLE STAGE THERMOSTAT 2 2 STAGE THERMOSTAT 2ND STAGE ON DELAY EXPIRED? RECOGNITION DELAY (30 SECONDS) EXPIRED? ONLY FOR 1ST REQUEST FOR 2ND STAGE HEAT YES YES INDUCER SWITCHED TO HIGH SPEED HIGH PRESSURE SWITCH CLOSED WITHIN 10 SECONDS? NO INDUCER SWITCHED TO LOW SPEED 5 MINUTE DELAY (ERROR CODE FLASHES) 3 YES 2ND STAGE GAS VALVE ENERGIZED INDOOR BLOWER ENERGIZED ON
Troubleshooting: Heating Sequence of Operation (Continued) CALL FOR HEAT SATISFIED FIRST−STAGE HEAT SECOND−STAGE HEAT 2 3 RUN MODE: 1ST OR 2ND STAGE CALL FOR HEAT.
Troubleshooting: Cooling Sequence of Operation (Continued) CALL FOR COOLING 1 1ST STAGE COOLING REQUEST RECEIVED 1 WAIT FOR COMPRESSOR TIMED OFF DELAY TO EXPIRE ENERGIZE 1ST STAGE COOLING CONTACTOR (COMPRESSOR & FAN) INDOOR BLOWER 2 SECOND ON DELAY ENERGIZE INDOOR BLOWER 2 (LOW COOLING MODE) MAINTAIN INDOOR BLOWER (LOW COOLING MODE) 1 2ND STAGE COOLING REQUEST? YES ENERGIZE 2ND STAGE COOLING CONTACTOR (COMPRESSOR & FAN) YES YES 1ST STAGE COOLING REQUEST STILL ACTIVE? NO YES ENERGIZE INDOOR BLOWER 2 (H
Troubleshooting: Continuous Fan Sequence of Operation CALL FOR FAN 1 CALL FOR FAN INDOOR BLOWER ON CONTINUOUS FAN SPEED NO CALL FOR FAN REMOVED? MAINTAIN INDOOR BLOWER AT CONTINUOUS FAN YES REQUEST FOR COOLING RECEIVED? YES MAINTAIN INDOOR BLOWER AT CONTINUOUS FAN 4 GO TO CALL FOR COOLING INDOOR BLOWER OFF 1 GO TO CALL FOR 1ST STAGE HEAT NO REQUEST FOR HEAT RECEIVED? YES NO DE−ENERGIZE INDOOR BLOWER 1 Page 72
