Table of Contents
Advertisement
Библиотека СОК
Service Literature
The LGA / LCA 3, 3.5, 4, 5 and 6 ton (10.5, 12.3, 14, 17.5 and
21 kW) units are configure to order units (CTO) with a wide
selection
of
LGA/042/048/060/072 gas/electric packaged rooftop units
are available in 78,000, 92,000 or 125,000 Btuh (22.85, 27, or
36.6 kW) heating inputs, with the LGA036 available only in
78,000 heating input. Gas heat sections are designed with
Lennox' aluminized or optional stainless steel tube heat ex-
changers. The LCA cooling packaged rooftop units are
equipped with the same cooling sections as the LGA units.
Optional electric heat is factory-or field-installed in LCA units.
Electric heat operates in single or multiple stages depending
on the kW input size. 7.0 kW through 30kW heat sections are
available. LGA and LCA units have identical refrigerant cir-
cuits with 3, 3.5, 4, 5 and 6 ton (10.5, 12.3, 14, 17.5 and 21
kW) cooling capacities. LGA/LCA units utilize one compres-
sor.
The LGA and LCA units are designed to accept any of sev-
eral different energy management thermostat control sys-
tems with minimum field wiring. Factory or field provided
control options connect to the unit with jack plugs. When
"plugged in" the controls become an integral part of the unit
wiring.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub-
ject to change. Procedures outlined in this manual are pre-
sented as a recommendation only and do not supersede or
replace local or state codes.
If the unit must be lifted for service, rig unit by attaching
four cables to the holes located in the unit base rail (two
holes at each corner). Refer to the installation instruc-
tions for the proper rigging technique.
!
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.
factory
installed
options.
WARNING
Corp. 9822-L12
Revised 09/2001
LGA / LCA SERIES
The
Page 1
LGA/LCA
3.0 to 6.0 TON
10.5 to 21 kW
LGA060 (5 TON) SHOWN
LCA060 (5 TON) SHOWN
ã 1998 Lennox Industries Inc.
Litho U.S.A.
Advertisement
Table of Contents
Related Manuals for Lennox LGA Series
Summary of Contents for Lennox LGA Series
- Page 1 36.6 kW) heating inputs, with the LGA036 available only in 78,000 heating input. Gas heat sections are designed with Lennox’ aluminized or optional stainless steel tube heat ex- changers. The LCA cooling packaged rooftop units are equipped with the same cooling sections as the LGA units.
- Page 2 TABLE OF CONTENTS VI-MAINTENANCE Introduction ......Page 1 ..... . Pages 40 Specifications Pages .
- Page 3 ¢Using total air volume and system static pressure requirements determine from blower performance tables rpm and motor output required. Maximum usable output of motors furnished by Lennox are shown. In Canada, nominal motor output is also maximum usable motor output. If motors of comparable output are used, be sure to keep within the service factor limitations outlined on the motor nameplate.
- Page 4 ¢Using total air volume and system static pressure requirements determine from blower performance tables rpm and motor output required. Maximum usable output of motors furnished by Lennox are shown. In Canada, nominal motor output is also maximum usable motor output. If motors of comparable output are used, be sure to keep within the service factor limitations outlined on the motor nameplate.
- Page 5 ELECTRICAL DATA 3-31/2 TON Model No. LCA/LGA036 208/230v - 208/230v- 460v 575v Line voltage data — 60 Hz 1 phase 3 phase 3 phase 3 phase Full load amps Outdoor Outdoor Fan Motor Fan Motor Locked rotor amps 0.75 0.75 0.75 0.75 Motor...
- Page 6 ELECTRICAL DATA 4-5 TON Model No. LCA/LGA048 208/230v 208/230v 460v 575v Line voltage data — 60 Hz 1 phase 3 phase 3 phase 3 phase Full load amps Outdoor Outdoor Fan Motor Fan Motor Locked rotor amps 0.75 0.75 0.75 0.75 Motor Motor...
- Page 7 ELECTRICAL DATA 6 TON Model No. LCA/LGA072 208/230v 460v 575v Line voltage data — 60 Hz 3 phase 3 phase 3 phase Full load amps Outdoor Outdoor Fan Motor Fan Motor Locked rotor amps Motor Motor Output Output Indoor Indoor Blower Blower Full load amps...
- Page 8 OPTIONAL ELECTRIC HEAT ACCESSORIES-LCA UNITS UNIT FUSE BLOCKS WITH ELECTRIC HEAT LCA036 LCA036 LCA042 LCA042 LCA048 LCA048 LCA060 LCA060 LCA072 Unit Model No. LCA072H Model No. EHA (see Electric Heat Data tables for additional information) Electric Electric 10, 15, 20, Heat kW Input Range 7, 10 15 &...
- Page 9 BELTDRIVE BLOWER DATA BLOWER TABLE INCLUDES RESISTANCE FOR LCA BASE UNIT ONLY WITH DRY INDOOR COIL AND AIR FILTERS IN PLACE. ADD: 1 - Wet indoor coil air resistance of selected unit. 2 - Any factory installed options air resistance (electric heat section, economizer, etc.) 3 - Any field installed accessories air resistance (duct resistance, diffuser, etc.) Then determine from blower table blower motor output and drive required.
- Page 10 *Using total air volume and system static pressure requirements determine from blower performance tables rpm and motor output required. Maximum usable output of motors furnished by Lennox are shown. In Canada, nominal motor output is also maximum usable motor output. If motors of comparable output are used, be sure to keep within the service factor limitations outlined on the motor nameplate.
- Page 11 BLOWER DATA AIR RESISTANCE - FACTORY INSTALLED OPTIONS/FIELD INSTALLED ACCESSORIES Total Resistance — inches water gauge (Pa) Air Volume Air Volume Wet Indoor Coil Electric Heat Electric Heat LCA/LGA LCA/LGA LCA/LGA072H Economizer (LCA Models) 036S/036H/042S/ 048H/060H/072S (3 row) (4 row) 042H/048S/060S (2 row) 0.02 (4) 0.04 (9)
- Page 12 LGA PARTS ARRANGEMENT HEAT EXCHANGER EVAPORATOR COIL FILTER ECONOMIZER (OPTIONAL) CONDENSER FAN CONTROL PANEL COMPRESSOR COMBUSTION AIR BLOWER DISCONNECT (OPTIONAL) GAS VALVE 120V GFI OUTLET (OPTIONAL) BURNERS BLOWER FIGURE 1 LCA PARTS ARRANGEMENT EVAPORATOR COIL CONDENSER FAN FILTERS CONTROL PANEL ECONOMIZER (OPTIONAL) COMPRESSOR...
- Page 13 LCA/LGA036-042-048-060-072 DIRECT DRIVE MOTOR TRANSFORMER (T1) MAIN CONTROL (A55) TERMINAL STRIP (TB34) ECONOMIZER MODULE (A56) FAN RELAY (K10) POWER EXHAUST RELAY (K65) BLOWER CONTACTOR (K3) HEAT RELAY (K36) COMPRESSOR (K1) LCA/LGA036-042-048-060-072 BELT DRIVE MOTOR TERMINAL STRIP (TB34) TRANSFORMER (T1) 3 PHASE HIGH EFFICIENCY ONLY ECONOMIZER MODULE (A56) RELAY (K10)
-
Page 14: I-Unit Components
I-UNIT COMPONENTS 6-Outdoor Fan Capacitor C1 (three phase units) LGA / LCA units are configure to order units (CTO). The Fan capacitor C1 is used to assist in the start up of condens- LGA and LCA unit components are shown in figures 1 and 2. L1, L2, and L3 wiring is color coded;... - Page 15 11-Power Exhaust Relay K65 (PEF units) ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures Power exhaust relay K65 is a DPDT relay with a 24VAC CAUTION coil. K65 is used in all LGA/LCA units equipped with the optional power exhaust fans. K65 is energized by the economizer control panel (A56), after the economizer Electrostatic discharge can affect electronic components.
- Page 16 SIEMENS OVERLOAD RELAY BLUE RESET BUTTON IN FACTORY-SET AUTO MODE (Turn clockwise to H for GREEN TRIP INDICATOR manual reset) (Flush with surface -- not tripped; Above surface -- tripped) RED TEST BUTTON AMP ADJUSTMENT DIAL Adjust relay amp setting according to value given on the blower motor nameplate. Proper relay amp setting equals motor nameplate FLA X service factor of 1.15 X .95.
-
Page 17: Crankcase Heater
LGA/LCA PLUMBING COMPONENTS SCROLL COMPRESSOR (B1) LOW PRESSURE SWITCH (S87) HIGH PRESSURE LOW AMBIENT SWITCH (S4) SWITCH (S11) DISCHARGE LINE SERVICE VALVE LIQUID LINE SERVICE VALVE PRESSURE TAP CRANKCASE HEATER (HR1) RECIPROCATING COMPRESSOR (B1) LOW PRESSURE SWITCH (S87) LOW AMBIENT SWITCH (S11) DISCHARGE LINE SERVICE VALVE... - Page 18 B-Cooling Components 3-Crankcase Heaters HR1 (all units) LGA/LCA units use independent cooling circuits consisting All LGA/LCA units with scroll compressors use belly-band of separate compressor, condenser coil and evaporator coil. type crankcase heaters, while all LGA/LCA units with recip- See figure 7. Units are equipped with a draw-through type rocating compressors use insertion type heaters.
- Page 19 C-Blower Compartment The main control module A55 governs the low pressure switches by shunting the switches during start up until pres- Overview sure is stabilized. After the shunt period, the control has a Units may be equipped with direct-drive or belt-drive blow- three-strike counter, during first thermostat demand, before the ers.
-
Page 20: Temperature Rise
1- Blower operation is dependent on the thermostat control LGA/LCA SUPPLY system option that has been installed in the LGA/LCA AIR BLOWER TRANSITION units. Refer to operation sequence of the control system BELT DRIVE SHOWN BLOWER installed for detailed descriptions of blower operation. REMOVE SCREWS (4) TO DIVIDER PANEL 2- Generally, blower operation is set at the thermostat fan... -
Page 21: Blower Speed Adjustment
4-Blower Speed Adjustment TABLE 3 To Change Blower Speed: Leadless 460V Blower Motor Speed Plug (J38) (208/230V Direct-Drive Units) Cooling 1- Referring to blower performance tables in front of this Cooling Heating Plug Wire Color manual, use the static pressure and blower speed tap to determine unit CFM. - Page 22 BLOWER SPEED ADJUSTMENT BLOWER TO INCREASE CFM TURN PULLEY CLOCKWISE SET SCREW TO INCREASE BELT TENSION 1 - Loosen 2 locking bolts. 2 - Pull motor mounting plate. 3 - Tighten motor mounting plate so plate is vertical. MOTOR PULLEY TO DECREASE CFM BLOWER PULLEY MOTOR...
- Page 23 LGA HEAT EXCHANGER HEAT EXCHANGER TUBE COMBUSTION AIR BLOWER BAFFLE VALVE FLUE BOX VENT CONNECTOR BURNERS FIGURE 13 E-GAS HEAT COMPONENTS (LGA units) Flame rectification sensing is used on all LGA units. Loss of flame during a heating cycle is indicated by an ab- LGA036 units are available in 78,000 Btuh (22.9 kW) sence of flame signal (0 microamps).
- Page 24 burners do not ignite, the ignition control will attempt to ignite JOHNSON IGNITION CONTROL the burners up to two more times. If ignition cannot be obtained after the third attempt, the control will lock out. The ignition con- LED CODES trol is not adjustable.
- Page 25 Each orifice and burner are sized specifically to the unit. The burners are controlled by the spark electrode, flame sens- Refer to Lennox Repair Parts Listing for correct sizing in- ing electrode, gas valve and combustion air blower. The spark formation.
- Page 26 A55. The switch actuates at 0.31” gas valve components. Tables 5 and 6 show factory set W.C. negative pressure + 0.05” W.C. (77Pa+ 12.4 Pa) on a gas valve manifold pressures for LGA series units. Page 26...
- Page 27 11-Spark Electrodes WHITE-RODGERS 36C76 GAS VALVE TWO STAGE An electrode assembly is used for ignition spark. The STAGE 2 MANUAL MANIFOLD MANIFOLD INLET electrode is mounted through holes on the left-most end PRESSURE ADJUSTMENT PRESSURE PRESSURE SCREW UNDER CAP TAP (SIDE) of the burner support.
- Page 28 TABLE 7 ELECTRIC HEAT DATA LCA036(S)(H), LCA042(S)(H), LCA048(S)(H) { { Total Unit (with Power Exhaust Fan) & *Heater Only Electric Heat Electric Heat Minimum Circuit Ampacity kW Size kW Size No. of No. of Volts Volts Btuh Btuh Model No., Voltage Model No., Voltage Sub-Fuse Box Sub-Fuse Box...
- Page 29 TABLE 8 ELECTRIC HEAT DATA LCA060(S)(H) { { Total Unit (with Power Exhaust Fan) & Electric Heat *Heater Only kW Size kW Size No. of No. of Volts Volts Btuh Btuh Electric Heat Minimum Circuit Ampacity Model No., Voltage Model No., Voltage Sub-Fuse Box Sub-Fuse Box Required...
- Page 30 TABLE 9 ELECTRIC HEAT DATA LCA072(S)(H) { { Total Unit (with Power Exhaust Fan) & *Heater Only Electric Heat Electric Heat Minimum Circuit Ampacity kW Size kW Size No. of No. of Volts Volts Btuh Btuh Model No., Voltage Model No., Voltage Sub-Fuse Box Sub-Fuse Box Required...
- Page 31 F-Optional Electric Heat Components 4-High Temperature Limits S15 (Primary) S15 is a SPST N.C. auto-reset thermostat located on the Tables 7 through 9 show all possible LCA to EHA matchups electric heat section . S15 is the high temperature limit for and electrical ratings.
- Page 32 ELECTRIC HEAT SECTION EHAFB FUSE BOX J2 P2 ELECTRIC ELEMENT /CONTROL ASSEMBLY WIRE TIES FIGURE 24 PARTS ARRANGEMENT FOR ELECTRIC HEAT SECTION EHA SERIES UNITS 3 THROUGH 5 TONS, EHA060-15-1P SHOWN Contactor K15 Secondary Switch S20 Secondary Switch S20 Contactor K16 Primary Switch S15 Contactor K17 (EHA060-15/20/25-1P ONLY)
- Page 33 II-PLACEMENT AND INSTALLATION TABLE 10 LGA/LCA036H Make sure the unit is installed in accordance with the Outdoor Coil DIscharge Suction +5 installation instructions and all applicable codes. See Entering Air Temp +10psig psig accessories section for conditions requiring use of the 65_F optional roof mounting frame (LARMF 03/07).
- Page 34 TABLE 15 TABLE 18 LGA/LCA048S LGA/LCA072H Outdoor Coil Outdoor Coil DIscharge Suction +5 DIscharge Suction +5 Entering Entering +10psig psig +10psig psig Air Temp Air Temp 65_F 65_F 75_F 75_F 85_F 85_F 95_F 95_F 105_F 105_F 115_F 115_F TABLE 19 TABLE 16 LGA/LCA072S LGA/LCA060H...
- Page 35 IV-STARTUP - OPERATION B-Cooling Startup LGA/LCA NOTE-Crankcase heaters must be energized 24 hours be- Refer to startup directions and refer closely to the unit wir- fore attempting to start compressor. Set thermostat so that ing diagram when servicing. See unit nameplate for mini- there is no demand to prevent compressor from cycling.
-
Page 36: For Your Safety Read Before Lighting
C-Heating Startup LGA 1-Placing Furnace In Operation FOR YOUR SAFETY READ BEFORE LIGHTING WARNING WARNING Danger of explosion and fire. Can cause injury or product or property damage. Electric shock hazard. Can cause injury You must follow these instructions or death. Do not use this furnace if any exactly. - Page 37 3- Remove heat section access panel. piping. The use of specialty Gas Leak Detector is to OFF. Depress 4- Turn knob on gas valve clockwise strongly recommended. It is available through Lennox to OFF. knob and turn clockwise under part number 31B2001.
-
Page 38: High Altitude Derate
3-Testing Gas Supply Pressure Manifold Adjustment Procedure 1- Connect test gauge to the outlet pressure tap on the When testing gas supply pressure, connect test gauge to the gas valve. Start the unit (call for second stage heat) inlet pressure tap (field provided - figure 28). Test supply gas and allow five minutes for the unit to reach steady pressure with unit firing at maximum rate (both stages en- state. - Page 39 7-Inshot Burner 9-Spark Electrode Gap Burners are factory set for maximum air and cannot be ad- The spark electrode assembly can be removed for inspection justed. Always operate unit with access panel in place. A peep by removing two screws securing the electrode assembly hole is furnished in the heating access panel for flame viewing.
-
Page 40: Vi-Maintenance
11-Combustion Air Blower B-Lubrication The combustion air blower is factory set and is not field adjust- All motors and blower wheels used in LGA / LCA units able. However, operation should be monitored to ensure prop- are prelubricated; no further lubrication is required. er operation. - Page 41 LGA / LCA units. A-LARMF03/07-14,24 Mounting Frames UNIT BASE RAIL When installing either the LGA / LCA units on a combustible surface for downflow discharge applications, the Lennox FIBERGLASS LARMF03/07 14-inch or 24-inch height roof mounting frame is INSULATION used.
- Page 42 It should be sprayed with Filter Handicoater when dry prior to reinstallation. Filter Handicoater is R.P. Products coating no. 418 and is available as Lennox Part No. P-8-5069. LAOADM MOTORIZED OUTDOOR AIR DAMPER E-LAREMD03/07 Economizer...
- Page 43 Motorized Outdoor Air Damper - The “GLO” mode is also “TMP” MODE (SENSIBLE TEMPERATURE) used when a motorized outdoor air damper is installed in In the “TMP” mode, the IMC uses input from the factory the system regardless of whether an energy management installed RT6 Supply Air Sensor, RT16 Return Air Sensor, and system is used.
- Page 44 1- Transformer (T20) is a 600V to 120/240V stepdown trans- 2- Electronic thermostat (see price book) former mounted in the blower compartment. Any two stage heat / two stage cool electronic ther- mostat may be used. 2- T20 has two in line fuses (F20), one on each leg of the trans- former.
- Page 45 VIII- WIRING DIAGRAMS / SEQUENCE OF OPERATION LGA/LCA036/072 P VOLTAGE Page 45...
- Page 46 LGA/LCA036/072 Y VOLTAGE Page 46...
- Page 47 LGA/LCA036/072 G, J, M, VOLTAGE Page 47...
-
Page 48: Blower Operation
SEQUENCE OF OPERATION LGA/LCA036/072 Power: 1st Stage Cooling 1. Line voltage from unit disconnect energizes transform- 6. Cooling demand energizes Y1 and G in the thermostat. G er T1. T1 provides 24VAC power to terminal strip energizes blower. TB34. TB34 provides 24VAC to the unit thermostast 7. - Page 49 LGA036/072 GAS HEAT UNIT WIRING DIAGRAM Page 49...
- Page 50 SEQUENCE OF OPERATION LGA036/072 GAS HEAT First or Single Stage Heat: 7. A second stage heating demand is received by A55 control module. 1. Heating demand initiates at W1 in the thermostat. 8. A55 energizes W2 terminal (high fire) of gas valve 2.
- Page 51 C2 diagram ELECTRONIC OR ELECTROMECHANICAL THERMOSTAT SEQUENCE OF OPERATION C2 DIAGRAM - ELECTRONIC OR ELECTROMECHANICAL THERMOSTAT POWER: Terminal strip TB34 energizes the thermostat components with 24VAC via TB1. OPERATION: The main control module A55 proves the optional N.O. filter switch S27(indicates dirty filter when closed), optional N.O. air flow switch S52(indicates no air [i.e.
-
Page 52: Operation
“L” SERIES ECONOMIZER SEQUENCE OF OPERATION L” SERIES ECONOMIZER POWER: Terminal strip TB34 energizes the economizer components with 24VAC. OPERATION: The main control module A55 along with outdoor enthalpy sensor A7 and indoor enthalpy sensor A62 (if differential enthalpy is used) communicates to the economizer control module A56 when to power the damper motor B7. - Page 53 EHA-7 / 30kW Y VOLTAGE Page 53...
-
Page 54: Heating Elements
Sequence of Operation -EHA 7 / 30kW - Y and G, J, M NOTE: This sequence of operation is for all Electric SECOND STAGE HEAT: Heat kW ratings and Y through J voltages. Each step 5 - With the first stage heat operating, an additional heat- of operation is numbered and can be followed in se- ing demand initiates at W2 in the thermostat. -
Page 55: Service Notes
SERVICE NOTES Page 55...