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S e r v i c e L i t e r a t u r e
EL280UHEK series units are 80% efficiency gas furnac-
es used for upflow or horizontal applications only, manu-
factured with Lennox Duralok heat exchangers formed of
aluminized steel. Units are available in heating capacities
of 44.000 to 110,000 Btuh and cooling applications up to
5 tons. Refer to Engineering Handbook for proper sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LPG operation. EL280UHEK
unit meets the California Nitrogen Oxides (NOx) Stan-
dards and California Seasonal Efficiency requirements. All
units use a redundant gas valve to assure safety shut-off
as required by C.S.A.
All specifications in this manual are subject to change.
Procedures outlined in this manual are presented as a
recommendation only and do not supersede or replace lo-
cal or state codes. In the absence of local or state codes,
the guidelines and procedures outlined in this manual (ex-
cept where noted) are recommendations only and do not
constitute code.
WARNING
This furnace is equipped with an ignition control
factory enabled for use with Lennox A2L refrigerant
systems.
Disabling
functionality on A2L system is prohibited by safety
codes. Refer to furnace installation instructions for
non-A2L and non-Lennox refrigerant system setup.
TABLE OF CONTENTS
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Blower Performance Data . . . . . . . . . . . . . . . . . . Page 5
Parts Identification. . . . . . . . . . . . . . . . . . . . . . . . Page 7
I Unit Components . . . . . . . . . . . . . . . . . . . . . . . . Page 8
II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26
IV Heating System Service Checks . . . . . . . . . Page 26
V Typical Operating Characteristics . . . . . . . . . Page 30
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 31
VII Wiring and Sequence of Operation . . . . . . Page 34
VIII Field Wiring and DIP Switch Settings . . . . Page 38
IX Troubleshooting Flow Chart . . . . . . . . . . . . . Page 42
UNIT INFORMATION
UNIT INFORMATION
EL280UHEK(X) With R-454B SERIES UNITS
the
refrigerant
detection
100168
Improper
installation,
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.
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.
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.
Page 1
EL280UHEK(X)
C C C C
I I I I
HI
HI
WARNING
adjustment,
WARNING
CAUTION
.
alteration,
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Summary of Contents for Lennox EL280UHEK
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Page 1: Table Of Contents
S e r v i c e L i t e r a t u r e EL280UHEK(X) With R-454B SERIES UNITS EL280UHEK series units are 80% efficiency gas furnac- es used for upflow or horizontal applications only, manu- factured with Lennox Duralok heat exchangers formed of aluminized steel. -
Page 2: Specifications
SP ECIF ICATIONS Model EL280UH045E36AK EL280UH070E36AK EL280UH090E36BK Heating Model No. - Low NOx - - - EL280UH070XE36AK - - - Performance AFUE High Input - Btuh 44,000 66,000 88,000 Fire Output - Btuh 35,000 54,000 71,000 Temperature rise range - °F 30 - 60 30 - 60 35 - 65... - Page 3 OPT IONAL AC C ESSORIES - ORD ER SEPARAT ELY “A” Width “B” Width “C” Width Models Models Models CABINET Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 Return Air Base - Upflow only 65W75 50W98 50W99 High Performance Economizer (Commercial only) 10U53 10U53 10U53...
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Page 4: Blower Performance Data
BLOWER D ATA EL280UH045E36AK PERFORMANCE (Less Filter) Air Volume / Watts at Various Blower Speeds External Static High Medium-High Medium Medium-Low Pressure (Black) (Brown) (Blue) (Yellow) (Red) in. w.g. Watts Watts Watts Watts Watts 0.10 1436 1199 1022 0.20 1431 1166 0.30 1413... - Page 5 BLOWER DATA EL280UH090E48BK PERFORMANCE (Less Filter) Air Volume / Watts at Various Blower Speeds External Static High Medium-High Medium Medium-Low Pressure (Black) (Brown) (Blue) (Yellow) (Red) in. w.g. Watts Watts Watts Watts Watts 0.10 1724 1514 1392 1308 1182 0.20 1691 1477 1354...
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Page 6: Parts Arrangement
PARTS ARRANGEMENT Make Up Box Heat Exchanger Combustion Air Inducer Combustion Air Pressure Switch Gas Valve and Manifold Assembly Collector Box Indoor Blower and Motor Assembly (installed in cabinet) Limit Switch (under collector box) Constant Torque Indoor Blower Motor (removed from cabinet) Two-Stage Integrated Control FIGURE 1 Page 6... -
Page 7: I Unit Components
A 24V circuit breaker is also located in the control box. EL280UHEK units are factory equipped with a bottom re- The switch provides overcurrent protection to the trans- turn air panel in place. The panel is designed to be field former (T1). - Page 8 Electronic Ignition The unit will switch to second stage heat after a “recog- nition period”. DIP switch 2, labeled SECOND STAGE At the beginning of the heat cycle the integrated control DELAY, is factory set in the OFF position for a 7 minute monitors the first stage and second stage combustion air recognition period.
- Page 9 TWO STAGE CONSTANT TORQUE, NON-COMMUNICATING 107897-XX FIGURE 4 TABLE 2 TABLE 3 THERMOSTAT INPUT TERMINALS LOW GWP INTERFACE LOW STAGE HEAT LGWP1 LOW GWP SENSOR #1 INTERFACE HIGH STAGE HEAT LGWP2 LOW GWP SENSOR # 2 INTERFACE ALARM INTERFACE TO LOW GWP LEAK AUDIBLE ALARM (DRY CONTACT) LOW STAGE COOL (when W915 is clipped) ZONE...
- Page 10 TABLE 4 DIAGNOSTIC CODES / STATUS OF FURNACE CODE IDLE MODE (DECIMALBLINKS AT 1 HERTZ -- 0.5 SECONDS ON, 0.5 SECONDS OFF INDOOR BLOWER OPERATION: CONTINUOUS FAN MODE (COSTANT TORQUE ONLY) INDOOR BLOWER OPERATION: FOLLOWED BY CFM SETTING FOR INDOOR BLOWER (1 SECOND ON, 0.5 SECOND OFF) / CFM SETTING FOR MODE DISPLAYED (VARIALBE SPEED ONLY) COOLING STAGE (1 SECOND ON, 0.5 SECOND OFF) 1 OR 2 DISPLAYED / PAUSE / REPEAT...
- Page 11 TABLE 4 Continued SOFT LOCKOUT FAULTS (60 MINUTES) GAS VALVE RELAY (1ST OR 2ND STAGE) CONTACT SHORTED E205 HOT SURFACE IGNITOR (HSI) SENSED OPEN E207 SOFT LOCKOUT-FLAME FAILURE ON IGNITION, IGNITION RETRY>MAX, LAST FAILED E270 RETRY DUE TO FLAME FAILURE SOFT LOCKOUT-PRESSURE SWITCH OPEN, IGNITION RETRY>MAX, LAST FAILED RETRY E271 DUE TO LPSW OPEN...
- Page 12 INTEGRATED CONTROL CONFIGURATION 2ND STAGE HEAT ON DELAY 7 MIN UPSTAGE DELAY 12 MIN UPSTAGE DELAY COOLING BLOWER-OFF DELAY HEATING BLOWER −OFF DELAY *45 SECOND 90 SECOND COOL BLOWER HTG BLOWER OFF DELAY OFF DELAY 60 SECOND HTG BLOWER OFF DELAY 2 SECOND COOL BLOWER 120 SECOND...
- Page 13 Integrated Control DIP Switches TABLE 5 EL280UHEK units are equipped with a two-stage integrat- Blower Off Heating Mode Delay Switch Settings ed control. This control manages ignition timing, heating Blower Off Delay mode fan off delays and indoor blower speeds based on...
- Page 14 Indoor Blower Speeds 1 - When the thermostat is set to “FAN ON,” the indoor blower will run continuously on the low speed when there is no cooling or heating demand. See TABLE 8 for allowable circulation speeds. 2 - 2 When the EL280UH(X)EK is operating in the high-fire or low-fire heating mode, the indoor blower will run on the corresponding heating speed.
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Page 15: Blower Wheel Replacement
Each blower is statically and dynamically balanced in Blower Housing as an assembly before installation in the unit. EL280UHEK units are equipped with a constant torque ECM motor. It has a DC motor coupled to an electronicco- ntrol module both contained in the same motor housing. - Page 16 Multi−Meter (set to VAC) Multi−Meter (set to VAC) "9A” Test 3 (if necessary) NOTE- Ignition control illustration is typical "7A” Check for 120 volts across terminals “L1” and “Neutrals” on the integrated control. If voltage is present, problem is with the har Turn power on to unit.
- Page 17 Replacing the Motor Module 3 - Check to see if the blower wheel spins freely. NOTE - Not all motors have field replaceable control mod- Motor Test ules. Only motors that utilize a 4 pin power connector and 5 pin signal connector as shown below may have replace- able controls.
- Page 18 C- Heating Components 4. Flame Rollout Switches (S47) 1. Ignitor The EL280UHEK is equipped with two rollout switches. See FIGURE 13 for location. The limits are a N.C. SPST The SureLight® ignitor is made of durable silicon nitride. manual-reset limit. When S47 senses rollout, the circuit...
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Page 19: Heating Components
HEATING COMPONENTS Ignitor Burners Rollout Switch Sensor Gas Valve Manifold and Gas Orifices FIGURE 13 Page 19... -
Page 20: Digital Meter
To Measure Flame Signal - Integrated Control: 6 - Turn supply voltage on and close thermostat contacts to cycle system. Use a digital readout meter capable of reading DC mi- 7 - When main burners are in operation for two minutes, croamps. - Page 21 Ignitor Check Out Test 1 Checking resistance of ignitor circuit Remove HSI/CAI 5-pin plug from integrated control. Check Ohms reading across terminal 1 and 5. Reading should be between 39 and 70 ohms. If value is correct, this is the only test needed. If the meter reading is not correct (”0”...
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Page 22: Combustion Air Pressure Switch
On heat demand (first or second stage) the switch senses that the combustion air inducer is operating. It closes a All EL280UHEK units use a two-stage combustion air in- circuit to the integrated control when pressure inside the ducer to move air through the burners and heat exchanger combustion air inducer decreases to a certain set point. - Page 23 Multiple Venting screws, rotate the combustion air inducer and gasket (pressure switch should be above the combustion air in- The EL280UHEK furnace can vent in multiple positions. ducer in all positions), then reinstall the mounting screws. See FIGURE 17. See unit Installation Instructions for more detail.
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Page 24: Ii-Placement And Installation
5 - Is the filter dirty or plugged? Dirty or plugged filters willcause the limit control to shut the unit off. EL280UHEK units are equipped with a hot surface 6 - Is gas turned on at the meter? ignition system. Do not attempt to light manually. - Page 25 Manifold For safety, shut unit off and remove manometer as pressure for the EL280UHEK can be measured at any soon as an accurate reading has been obtained. time the gas valve is open and is supplying gas to the unit.
- Page 26 Refer to TABLE 16 ple beyond the flue outlet. TABLE 15 shows acceptable for manifold pressure and TABLE 17 for pressure switch combustion for ALL EL280UHEK models. The maximum change and gas conversion kits. carbon monoxide reading should not exceed 100 ppm.
- Page 27 I- Proper Ground and Voltage 2 - In addition, measure the AC voltage from Line Hot to Line Neutral (spade terminals) on the integrated Furnace must be properly grounded for proper perfor- control. See FIGURE 20. This voltage should be in mance.
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Page 28: Typical Operating Characteristics
0.5” W.C. For cooling speed Temperature rise for EL280UHEK units depends on unit external static pressure drop must not be more than input, blower speed, blower horsepower and static pres- 0.8”... -
Page 29: Maintenance
At the beginning of each heating season, and to comply provide combustion air. with the Lennox Limited Warranty, your system should be checked by a licensed professional technician (or equiva- 10 - Inspect the furnace venting system to make sure... - Page 30 Cleaning the Heat Exchanger and Burners 12 - To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners. Visually NOTE - Use papers or protective covering in front of the inspect inside the burners and crossovers for any furnace during cleaning.
- Page 31 BURNER, COMBUSTION AIR INDUCER ASSEMBLY & HEAT EXCHANGER REMOVAL Gasket Pressure Switch Flue Transition Collector Box Heat Exchanger Ignitor Orifice Plate Combustion Air Inducer Retention Rings Rollout Switches Sensor Cross Over Manifold And Gas Valve FIGURE 23 Remove 5 screws if necessary NOx INSERTS (either side of cabinet) NOx Insert...
- Page 32 VII-Low GWP Applications WARNING For use with Lennox approved evaporator coil and LGWP sensors only. Use original manufacturer recommended LGWP sensors if using non Lennox approved evaporator coil. CONNECTING THE FURNACE CONTROL BOARD SENSOR. See FIGURE 34 and follow steps below: 1 - Route sensor wire #1 through provided grommet.
- Page 33 FURNACE CONTROL BOARD LOW GWP MODES OF 2. The furnace control board activates the blower (high OPERATION speed). The blower purges refrigerant from the cabinet, plenum, and ductwork. The modes of operation for the furnace control board are Initializing, Normal, Leak Detected, and Fault. 3.
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Page 34: Start-Up Procedure
LGWP TEST BUTTON FUNCTIONALITY External Alarm (For applications with external alarms wired directly to the The furnace control board is equipped with a Test/Reset furnace control board) push button. The Test button can be used to perform sev- The furnace control board triggers the external alarm sys- eral functions, depending on the mode of operation of the tem when it enters Leak Detected mode. - Page 35 BROWN BLUE YELLOW J135 J159 P136 110-60 BROWN YELLOW BLUE BLACK P159 WHT/BLK BLACK INDOOR GN/YLW BLOWER LENNOX MOTOR HEATING UNITS-GAS INTEGRATED EL280UH045E36AK EL280UH090XE48BK CONTROL EL280UH070E36AK EL280UH110E48CK EL280UH070XE36AK EL280UH110E60CK EL280UH090E36BK EL280UH110XE60CK EL280UH090E48BK WARNING- EQUIPMENT ELECTRIC SHOCK HAZARD,CAN CAUSE INJURY GROUND 2 HEAT 2 COOL OR DEATH.UNIT MUST BE GROUNDED IN ACCORDANCE...
- Page 36 When the delay ends, the indoor blower motor is ener- gized on the low fire heating speed, the HUM contacts The two-stage integrated control used in EL280UHEK close energizing the humidifier and 120V ACC terminal units has an added feature of an internal Watchguard is energized.
- Page 37 Applications Using A Single-Stage Thermostat 4 - After the 20-second warm-up period has ended, the gas valve is energized on low fire (first stage) See FIGURE 30 for heating operation and ignition occurs. At the same time, the control B - Heating Sequence -- Integrated Control Thermostat module sends a signal to begin an indoor blower Selection DIP Switch 1 ON in “Single-Stage”...
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Page 38: Field Wiring And Dip Switch Settings
Field Wiring and DIP Switch Settings DIP Switch Settings and On-Board Links DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 1 Heat / 1 Cool FURNACE OUTDOOR T'STAT TERM. STRIP UNIT NOTE - Use DIP switch 2 to set... - Page 39 DIP Switch Settings and On-Board Links DIP Switch 1 On Board Links Must Be Cut To Select Thermostat Thermostat Wiring Connections System Options Heating Stages 2 Heat / 2 Cool FURNACE OUTDOOR (M30 T-stat) T'STAT TERM. STRIP UNIT CUT ON-BOARD LINK W915 2 STAGE COMPR...
- Page 40 DIP Switch Settings and On-Board Links DIP Switch 1 Wiring Connections Thermostat On Board Links Must Be Cut To Select Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP T'STAT TERM. STRIP Single Stage Heat Pump CUT ON-BOARD LINK (M30 T-stat) W951 67M41*...
- Page 41 DIP Switch Settings and On-Board Links DIP Switch 1 Wiring Connections Thermostat On Board Links Must Be Cut To Select Thermostat Heating System Options Stages Dual Fuel FURNACE HEAT PUMP T'STAT TERM. STRIP Single Stage Heat Pump CUT ON-BOARD LINK (M30 T-stat) W951 67M41*...
- Page 42 IX- Troubleshooting HEATING SEQUENCE OF OPERATION NORMAL AND ABNORMAL HEATING MODE POWER ON GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF. (RESET CONTROL BY CONTROL SELF-CHECK OKAY? TURNING MAIN POWER OFF.) POLARITY REVERSED. POLARITY OKAY? STATUS ERROR CODE 5 + 4. IS THERE A SIGNAL HOLDS UNTIL UNIT IS PROPERLY GROUNDED.
- Page 43 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT STATUS LED - HEARTBEAT. (Refer to box A on previous page) GAS VALVE OFF. COMBUSTION AIR INDUCER FIRST-STAGE (LOW FIRE) PRESSURE OFF. INDOOR BLOWER OFF. UNIT WILL RETRY SWITCH CLOSED WITHIN 2.5 MINUTES? AFTER 5-MINUTE WAIT PERIOD.
- Page 44 HEATING SEQUENCE OF OPERATION CONTINUED THERMOSTAT CALLS FOR HEAT. STATUS LED -- HEARTBEAT. SEE BOX A. FLAME SIGNAL ABOVE ( 1.40 microamps) LOW FLAME SIGNAL (Does not affect control operation) STATUS ERROR CODE 1 + 2. SINGLE-STAGE THERMOSTAT MODE TWO STAGE THERMOSTAT MODE (DIP SWITCH SET AT “ON”) (DIP SWITCH SET AT “OFF”) START SECOND-STAGE RECOGNITION...
- Page 45 HEATING SEQUENCE OF OPERATION CONTINUED SEE BOX A NORMAL OPERATION. SEE BOX B THERMOSTAT CALLS FOR HEAT. RETURN TO FIRST-STAGE HEAT MODE. FIRST-STAGE CONTINUES UNTIL SECOND- STAGE PRESSURE SWITCH CAN BE PROVEN SECOND-STAGE (HIGH FIRE) HEAT or HEAT DEMAND IS SATISFIED. A FIVE (5) PRESSURE SWITCH CLOSED? MINUTE WAIT PERIOD IS INITIATED BEFORE RETRY.
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Page 46: Cooling Sequence Of Operation
COOLING SEQUENCE OF OPERATION POWER ON SIGNAL POLARITY REVERSED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS POLARITY REVERSED? IN THIS CONDITION. STATUS ERROR CODE 5 + 4. SIGNAL IMPROPER GROUND AT LED. CONTROL WILL CONTINUE TO CALL FOR COOLING IS THERE IN THIS CONDITION. - Page 47 CONTINUOUS LOW SPEED FAN SEQUENCE OF OPERATION MANUAL FAN SELECTION MADE AT THERMOSTAT. AFTER 2 SECOND DELAY, INDOOR BLOWER IS ENERGIZED ON CONTINUOUS FAN SPEED. THERMOSTAT CALLS FOR FIRST STAGE COOL. THERMOSTAT CALLS FOR FIRST-STAGE HEAT. INDOOR BLOWER RAMPS TO FIRST STAGE AFTER 45-SECOND DELAY, INDOOR BLOWER COOLING SPEED AFTER A 2-SECOND DELAY.
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