Lennox International Inc. SL280UH090V48B manual

Page 1 06/1 1 *2P0611* 506763−01 *P506763-01*  201 1 Lennox Industries Inc. Dallas, T exas, USA UPFLOW HORIZONT AL LEFT HORIZONT AL RIGHT AIR FLOW AIR FLOW AIR FLOW W ARNING Improper inst allation, adjustment, alteration, service or maintenance can cause property damage, person- al injury or loss of life. Inst allation and service must be perf[...]

Page 2 Unit Dimensions − inches (mm) 1 NOTE − 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 velocity) 2. Single side return air with optional RAB [...]

Page 3 Part s Arrangement FIGURE 1 HEA T EXCHANGER CABINET COMBUSTION AIR INDUCER BLOWER ASSEMBL Y BURNER BOX INNER BLOWER ACCESS P ANEL ACCESS P ANEL SIGHT GLASS COMBUSTION AIR INDUCER PRESSURE SWITCH GAS V AL VE CONTROL BOX (Includes two−stage integrated control, transformer and circuit breaker) ROLLOUT SWITCH[...]

Page 4 SL280UHV Gas Furnace The S L280UHV gas f urnace i s equipped with a t wo−stage, variable speed integrated control. the control is compat - ible with: Communicating thermostat s − icomfort T ouch ® . Non−comunicating thermostat s − ComfortSense or other conventional thermostat s. Control systems − Harmony III Zone Control System[...]

Page 5 T emperature Rise NOTE − Furnace must be adjusted to obtain a temperature rise(high a nd l ow f ire) within the r ange(s) s pecified o n the unit nameplate. Failure to d o so m ay cause erratic limit o peration and may result in premature heat exchanger failure. This SL280UHV furnace must be inst alled so that its elec- trical components a[...]

Page 6  Place the furnace as close to the center of the air dis- tribution system as possible. The furnace should also be located close to the chimney or vent termination point.  Do not install the f urnace where drafts might blow direct- ly into it. This could cause improper combustion and un- safe operation.  Do not block the furnace com[...]

Page 7 Unconfined Sp ace An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m 3 ) per 1,000 Btu (.29 kW) per hour of the com- bined input rating of all appliances installed in that space. This space also includes adjacent rooms which are not separated b y a door . Though an area [...]

Page 8 EQUIPMENT IN CONFINED SP ACE ALL AIR FROM OUTSIDE (Inlet Air from Crawlspace and Outlet Air to V entilated Attic) NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645 mm 2 ) per 4,000 Btu (1.17 kW) per hour of the tot al input rating of all equipment in the enclosure. VENTILA TION LOUVERS (Eac[...]

Page 9 Setting Equipment W ARNING Do not inst all the furnace on its front or it s back. Do no t connect the return ai r ducts to the back of the fur- nace. Doing so will adversely affect the operation of the safety control devices, which could result in per- sonal injury or death. The SL280UHV gas furnace can be installed as shipped in either the [...]

Page 10 Return Air −− Up flow Applications Return air can be brought in through the b ottom or either side o f the furnace installed in an upflow a pplication. If the furnace i s inst alled o n a plat form w ith bottom r eturn, m ake an a irtight s eal between t he b ottom of the furnace and the platform to ensure that the furnace operates prop[...]

Page 1 1 Removing the Bottom Panel Remov e the two screws that secure the bottom cap to the furnace. Pivot the bottom cap down to release the bottom panel. Once the bottom p anel has been removed, reinstall the bottom cap. See figure 10. Removing the Bottom Panel FIGURE 10 Screw Bottom Panel Bottom Cap H or i zon t a l A pp li ca ti on Installation[...]

Page 12 Horizontal Application Unit Installed on Plat form FIGURE 13 clearances. GAS ENTRY VENT PIPE See the unit nameplate for Line contact is permissible SERVICE PLA TFORM W ARNING Improper inst allation of the f urnace can result in per- sonal injury or death. Combustion and flue products must never be allowed to enter the return air system or t[...]

Page 13 V enting 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 . FIGURE 14 Mounting Screws Location mounting screws mounting screw UPFlow Position FIGURE 15 UPFLOW POSITION T op V ent Discharge FLOW AIR collector box[...]

Page 14 Horizontal Position FIGURE 18 HORIZONT AL LEFT POSITION T op V ent Discharge  Disconnect pressure switch hose from barbed fitting on the pres- sure switch assembly . Remove pressure switch assembly (1 screw) and cut wire tie to free pressure switch wires. Re−install pressure switch on the other side of orifice plate and re−connect pr[...]

Page 15 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 (NFP A 54 / ANSI Z223.1) in the USA. A fan−assisted Category I fur- nace is a n appliance equipped with an integral mechanical means to either draw or force combustion products thr[...]

Page 16 FIGURE 24 Common V enting Using Tile−Lined Interior Masonry Chimney and Combined V ent Connector MINIMUM LENGTH = AS SHORT AS PRACTICAL. FOR MAXIMUM LENGTH SEE NOTE TO LEFT INTERIOR TILE−LINED MASONRY CHIMNEY NOTE − the chimney must be properly sized per provided venting tables or lined with listed metal lining system. PERMANENTL Y SE[...]

Page 17 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 lat- eral lengths (tables 3 and 4) are assumed to have no elbows in the vent system. For all other vent configura- tions, the vent system is assumed to hav[...]

Page 18 T ABLE 3 Cap acity of T ype B Double−Wall V ent s with T ype B Double−Wall Connectors Serving a Single Category I Appliance Height H (feet) Lateral L (feet) V ent and Connector Diameter − D (inches) 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 6 0 0 78 0 152 0 251 0 37[...]

Page 19 T ABLE 4 Cap acity of T ype B Double−Wall V ent s with Single−Wall Met al Connectors Serving a Single Category I Appliance Height H (feet) Lateral L (feet) V ent and Connector Diameter − D (inches) 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 6 0 38 77 59 151 85 249 12[...]

Page 20 T ABLE 5 V ent Connector Capacity T ype B Double−W all V ent s with T ype B Double−Wall Connectors Serving T wo or More Category I Appliances V ent Height H (feet) Connector Rise R (feet) V ent and Connector Diameter − D (inches) 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MI[...]

Page 21 T ABLE 7 V ent Connector Capacity T ype B Double−W all V ent s with Single−Wall Met al Connectors Serving T wo or More Category I Appliances Height H (feet) Lateral L (feet) V ent and Connector Diameter − D (inches) 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 6 1 NR N[...]

Page 22 Removal of the Furnace from Common V ent In the event that an existing furnace is removed from a venting system commonly run with separate gas ap- pliances, the venting system is likely to be too large to properly vent the remaining attached appliances. Conduct t he following test while each a ppliance is operat- ing a nd t he o ther a ppli[...]

Page 23 Gas Piping CAUTION If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be in st alled at the gas valve and extend out side the furnace cabinet. The flexible connector can then be added between the black iron pipe and the gas supply line. Gas Supply 1 − This uni t i s sh ipp ed s[...]

Page 24 GROUND JOINT UNION AUTOMA TIC GAS V AL VE FIELD PROVIDED AND INST ALLED GROUND JOINT UNION Lef t Side Piping (St andard) Right Side Piping (Alternate) AUTOMA TIC GAS V AL VE DRIP LEG DRIP LEG MANUAL MAIN SHUT−OFF VA LV E (With 1/8 in. NPT Plugged T ap Shown) MANUAL MAIN SHUT−OFF VA LV E (With 1/8 in. NPT Plugged T ap Shown) NOTE − BLA[...]

Page 25 Electrical ELECTROST A TIC DISCHARGE (ESD) Precautions and Procedures CAUTION Electrost atic discharge can affect elec- tronic component s. T ake precautions to neutralize electrost atic charge by touching your hand and tools to metal prior to handling the control. The unit is equipped with a field make−up box on the left hand side of the[...]

Page 26 8 − An unpowered, normally open (dry) set of contac ts with a 1/4" spade terminal HUM" are provided for humidifi- er connections and may be connect ed 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 [...]

Page 27 FIGURE 30 icomfort T ouch ® Thermost at with SL280UHV and Non−Communicating Out door Unit icomfort  − ENABLED SL280UHV FURNACE icomfort T ouch® THERMOST A T NON−COMMUNICA TING OUTDOOR AIR CONDITIONING UNIT − 1 OR 2 ST AGE icomfort T ouch ® Thermostat icomfort  −Enabled SL280UHV Indoor Furnace Non−Communicating Outdoor A[...]

Page 28 Optional Accessories for use with any icomfort T ouch ® System FIGURE 31 NOTE: 24V UV LIGHT APPLICA TIONS In an icomfort by Lennox  system, neither furnace nor air handler trans- former will have adequate V A to power 24V UV light applications. An additional transformer for UV light applications is required. icomfort T ouch ® THERMOST [...]

Page 29 T ABLE 1 1 SL280 Field Wiring Applications With Conventional Thermost at Thermost at DIP Switch Settings and On−Board Links (See figure 34) Wiring Connections DIP Switch 1 Thermost at Heating St ages On Board Links Must Be Cut T o Select System Options 1 Heat / 1 Cool NO TE − Use DI P switch 2 to set second−stage heat ON delay . OFF?[...]

Page 30 T ABLE 1 1 SL280 Field Wiring Applications With Conventional Thermost at (Continued) Thermost at DIP Switch Settings and On−Board Links (See figure 34) Wiring Connections DIP Switch 1 Thermost at Heating St ages On Board Links Must Be Cut T o Select System Options 2 Heat / 2 Cool OFF CUT ON−BOARD LINK W915 2 ST AGE COMPR S1 T’STAT FUR[...]

Page 31 T ABLE 1 1 SL280 Field Wiring Applications With Conventional Thermost at (Continued) Thermost at DIP Switch Settings and On−Board Links (figure 34) Wiring Connections DIP Switch 1 Thermost at Heating St ages On Board Links Must Be Cut T o Select System Options Dual Fuel Single S tage Heat Pump ComfortSense 7000 L7724U thermostat w/ dual f[...]

Page 32 T ABLE 1 1 SL280 Field Wiring Applications With Conventional Thermost at (Continued) Thermost at DIP Switch Settings and On−Board Links (figure 34) Wiring Connections DIP Switch 1 Thermost at Heating St ages On Board Links Must Be Cut T o Select System Options Dual Fuel Single S tage Heat Pump ComfortSense 7000 L7724U thermostat w/ dual f[...]

Page 33 SL280UHV Schematic Wiring Diagram FIGURE 32[...]

Page 34 TYPICAL SL280UHV FIELD WIRING DIAGRAM FIGURE 33 FIELD INST ALLED CLASS II 24V FIELD INST ALLED LINE VOL T AGE[...]

Page 35 Integrated Control FIGURE 34 THERMOST A T CONNECTIONS (TB1) 1/4" QUICK CONNECT TERMINALS RS−BUS LINK (TB82, future use) I+ = DA T A HIGH CONNECTION I − = DA T A LOW CONNECTION RS−BUS OUTDOOR (TB83) R = 24V AC I + = DA T A HIGH CONNECTION I − = DA T A LOW CONNECTION C = 24V AXC COMMON RS−BUS INDOOR (TB84) R = 24V AC I + = DA T[...]

Page 36 Integrated Control DIP Switch Settings − Conventional Thermost at (non−communi- cating) SL280UHV units are equipped with a two−st age, 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 co[...]

Page 37 T ABLE 15 Cooling Mode Blower Speed Ramping Ramping Option Switch 9 Switch 10 A (Factory) Off Of f B Off On C On Off D On On Ramping Option A (Factory Selection)  Motor runs at 50% for 30 seconds.  Motor then runs at 82% for approximately 7−1/2 minu- tes.  If demand has not been satisfied after 7−1/2 minutes, motor runs at 100%[...]

Page 38 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. W ARNING Carefully review all configuration information pro- vided. Failure to properly set DIP switches, jumpers and on−board links can result in improper oper[...]

Page 39 BLO WER D A T A SL280UH070V36A BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1045 1 145 +18% 985 1080 +12% 940 1035 +6%[...]

Page 40 BLO WER D A T A SL280UH090V36B BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1300 1420 +18% 1250 1335 +12% 1 185 1285 +[...]

Page 41 BLO WER D A T A SL280UH090V48B BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1280 1410 +18% 1220 1340 +12% 1 155 1270 +[...]

Page 42 BLO WER D A T A SL280UH090V48B BLOWER PERFORMANCE (less lter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1295 1425 +18%[...]

Page 43 BLO WER D A T A SL280UH090V60C BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTT OM AND ONE SIDE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage[...]

Page 44 BLO WER D A T A SL280UH090V60C BLOWER PERFORMANCE (less lter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1360 1495 +18%[...]

Page 45 BLO WER D A T A SL280UH1 10V60C BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTT OM AND ONE SIDE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stag[...]

Page 46 BLO WER D A T A SL280UH1 10V60C BLOWER PERFORMANCE (less lter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1635 1800 +18[...]

Page 47 BLO WER D A T A SL280UH135V60D BLOWER PERFORMANCE (less lter) BOTTOM RETURN AIR, RETURN AIR FROM BOTH SIDES OR RETURN AIR FROM BOTT OM AND ONE SIDE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage[...]

Page 48 BLO WER D A T A SL280UH135V60D BLOWER PERFORMANCE (less lter) SIDE RETURN AIR WITH OPTIONAL RETURN AIR BASE 0 through 0.8 in. w .g. (Heating) and 0 through 1.0 in. w.g. (Cooling) External Static Pressure Range HEA TING 1 Heating Speed DIP Switch Settings First Stage Heating Speed - cfm Second Stage Heating Speed - cfm +24% 1840 2025 +18%[...]

Page 49 T ABLE 18 OPERA TING SEQUENCE SL280UHV , Non−Communicating Thermostat with Humidity Control Feature and Single−S peed Outdoor Unit OPERA TING SEQUENCE SYSTEM DEMAND SYSTEM RESPONSE System Condition S tep Thermostat Demand Relative Humidity Compres- sor Blower CFM (COOL) Comments Y1 O G W 1 S tatus D NO CALL FOR DEHUMIDIFICA TION Normal [...]

Page 50 T ABLE 19 OPERA TING SEQUENCE SL280UHV , Non−Communicating Thermostat with Humidity Control Feature and T wo−Speed Out door Unit OPERA TING SEQUENCE SYSTEM DEMAND SYSTEM RESPONSE System Condition St e p Thermostat Demand Relative Humidity Compressor Blower CFM (COOL) Comments Y1 Y2 O G W 1 W 2 S tatus D NO CALL FOR DEHUMIDIFICA TION Nor[...]

Page 51 Unit St art−Up FOR YOUR SAFETY READ BEFORE LIGHTING W ARNING D o not use this furnace if any part has been underwa- ter . Immediately call a licensed professional service technician (o r equivalent) to inspect the furnace and to replace any part of the control system and any gas control which has been under water . W ARNING If overheating[...]

Page 52 12− If the appliance will not operate, follow the instructions T urning Off Gas to Unit" and call your service techni- cian or gas supplier . T urning Off Gas to Unit 1 − Set the thermostat to the lowest setting. 2 − T u rn of f all electrical power to the unit if service is to be performed. 3 − Remove the upper access panel[...]

Page 53 High Altitude The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. T ables 22 through 25 shows manifold pressure, pressures switch and gas conversion kits at all altitudes. IMPORT ANT For safety , shut unit off and remove manometer as soon as an accurate[...]

Page 54 Other Unit Adjustment s Primary and Secondary Limit s The primary limit is located on the heating compartment vestibule panel. The secondary limits (if equipped) are lo- cated in th e b l ower comp artment, att ached to the back side of the blower . These auto reset limits are factory set and re- quire no adjustment. Flame Rollout Switches [...]

Page 55 Applications Using A Single−St age Thermost at See figure 38 for ignition control sequence B − Heating Sequence −− Integrated Control Thermostat Selection DIP Switch 1 ON in Single−St age" Position NOTE − In these applications, two−stage heat will be initi- ated by the integrated control if heating demand has not been [...]

Page 56 Service W ARNING 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 opera- tion, serious injury , death, or property damage. Before servicing, disconnect all electrical power to fur[...]

Page 57 SL280UHV BURNER, COMBUSTION AIR INDUCER ASSEMBL Y & HEA T EXCHANGER REMOV AL FIGURE 39 heat exchanger gasket collector box orifice plate flue transition pressure switch combustion air inducer burners burner box assembly burner box cover plate manifold and gas valve gasket retention rings cross over ignitor rollout switch sensor 9 − Re[...]

Page 58 SL280UHV NOX INSERTS FIGURE 40 FIGURE 41 Remove 5 screws if necessary (either side of cabinet) 1 2 3 4 5 18− Reconnect all wires. 19− Reconnect top cap and vent pipe to combustion air in- ducer outlet. 20− Reconnect gas supply piping. 21− T urn on power and gas supply to unit. 22− Set thermostat and check for proper operation. 23?[...]

Page 59 Planned Service Th e following items should be checked during an annual inspection. Power to the unit must be shut of f for the service techni- cian’s safety . Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) − Must be open and unob- structed to provide combustion air . Burners − Must be i nsp[...]

Page 60 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 th[...]

Page 61 Integrated Control Diagnostic Codes (continued) Code Diagnostic Codes/S tatus of Equipment Action Required to Clear and Recover E 105 Device communication problem − No other devices on RS BUS (Commu- nication system). Equipment is unable to communicate. Indicates numerous message errors. In most cases errors are related to electrical nois[...]

Page 62 Integrated Control Diagnostic Codes (continued) E 131 Corrupted control parameters (V erify configuration of system). Communi- cating only . Reconfigure the system. Replace control if heating or cooling is not available. Only applicable in the communicating mode, not in startup. Exit from Com- missioning and Execute ’Set Factory Default m[...]

Page 63 Integrated Control Diagnostic Codes (continued) Code Diagnostic Codes/S tatus 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 in- ducer for correct ope[...]

Page 64 Integrated Control Diagnostic Codes (continued) E 272 Sof t 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[...]

Page 65 Integrated Control Diagnostic Codes (continued) Code Diagnostic Codes/S tatus of Equipment Action Required to Clear and Recover E 312 Restricted air flow in cooling or continuous fan mode is lower than cfm setting. W arning Only . Restricted airflow − Indoor blower is running at a reduced CFM (Cutback Mode − The variable speed motor has[...]

Page 66 Integrated Control Diagnostic Codes (continued) E 406 LSOM − Compressor open st art circuit. Required amount of current is not passing through S tart current transformer . Clears the error after cur- rent is sensed in ST ART sensor , or after power re- set. E 407 LSOM − Compressor open run circuit. Required amount of current is not pass[...]

Page 67 Program Unit Cap acity/Size Mode Power−Up − Number displayed represents by integrated control unit size code (furnace model and capacity). If three horizont al 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 o[...]

Page 68 T roubleshooting: Heating Sequence of Operation HIGH LIMIT SWITCH CLOSED? LOW PRESSURE SWITCH OPEN? INDUCER ON PRE − PURGE (15 SECONDS) 1ST ST AGE GAS V AL VE ENERGIZED FLAME SENSED WITHIN 4 SECONDS? (LOW HEA T SPEED) HEA T F AN OFF DELA Y (LOW HEA T SPEED) AFTER HEA T F AN OFF DELA Y (LOW HEA T SPEED) YES YES YES YES ERROR CODE FLASHES O[...]

Page 69 T roubleshooting: Heating Sequence of Operation (Continued) WHEN USED WITH A SINGLE ST AGE THERMOSTA T , SET SW1 TO THE ON POSITION IN DIP SWITCH S4. IF THE HIGH FIRE PRESSURE SWITCH DOES NOT CLOSE WITHIN 5 A TTEMPTS, THE SYSTEM WILL OPERA TE A T LOW FIRE FOR THE REMAINDER OF THE CALL FOR HEA T REQUEST . 2ND ST AGE GAS V AL VE ENERGIZED ONL[...]

Page 70 T roubleshooting: Heating Sequence of Operation (Continued) 2ND ST AGE HEA T RUN MODE: 1ST OR 2ND ST AGE CALL FOR HEA T . ALL INPUTS MONITORED (LIMIT , PRESSURE, CALL FOR HEA T/COOL, FLAME LEVEL) 2ND ST AGE CALL FOR HEA T SA TISFIED? NO YES DE − ENERGIZE 2ND ST AGE GAS V AL VE INDUCER SPEED SWITCHED TO LOW SPEED 1 2 3 1ST ST AGE HEA T 1ST[...]

Page 71 T roubleshooting: Cooling Sequence of Operation (Continued) 1ST ST AGE COOLING REQUEST RECEIVED ENERGIZE 1ST ST AGE COOLING CONT ACTOR (COMPRESSOR & F AN) 2ND ST AGE COOLING REQUEST? NO YES YES YES NO 1ST ST AGE COOLING REQUEST STILL ACTIVE? NO YES YES ENERGIZE 2ND ST AGE COOLING CONT ACTOR (COMPRESSOR & F AN) DE − ENERGIZE 2ND ST[...]

Page 72 T roubleshooting: Continuous Fan Sequence of Operation CALL FOR F AN CALL FOR F AN REMOVED? YES NO NO REQUEST FOR HEA T RECEIVED? REQUEST FOR COOLING RECEIVED? GO TO CALL FOR 1ST ST AGE HEA T YES GO TO CALL FOR COOLING 1 1 1 4 YES NO CALL FOR FAN INDOOR BLOWER ON CONTINUOUS F AN SPEED MAINT AIN INDOOR BLOWER A T CONTINUOUS F AN MAINT AIN IN[...]