Specifications

SERVICE
GCS24
UNIT
INFORMATION
10-12.5 TON
Page 1
1993 Lennox Industries Inc.
Corp. 9360-L12 Litho U.S.A.
GCS24 SERIES
GCS24 10 and12.5 ton series units are packaged combina
tion twostage gas heat / twostage dx cool units designed
for commercial applications. Gas heat sections are de
signed with Lennox' aluminized steel tube heat exchangers
ranging in size from 170,000 to 270,000 Btuh input. Both
units are equipped with two compressors. Units are de
signed for rooftop or side of building installation with either
bottom or horizontal discharge and return air.
The GCS24 is designed to accept any of several different
thermostat control systems with minimum field wiring. Fac
tory or field provided control options connect to the unit with
jack plugs. When "plugged in" the controls become an inte
gral part of the unit wiring. Units are also equipped with a low
voltage terminal strip to facilitate thermostat field wiring.
Information contained in this manual is intended for use by
Lennox 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. In the absence of local or state
codes, the guidelines and procedures outlined in this manu
al (except where noted) are recommended only.
GCS24-1353 SHOWN
TABLE OF CONTENTS
Introduction Page 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications Page 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessories / Electrical Data Page 3. . . . . . . . . . . . . . . . . . . . . . . .
Blower / Accessory Air Resistance Data Pages 45. . . . . . . . . . .
Parts Arrangement Page 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I- APPLICATION Page 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II- UNIT COMPONENTS Pages 712. . . . . . . . . . . . . . . . . . . . . . . . .
Control Box Components Pages 78. . . . . . . . . . . . . . . . . . . . . . . .
Cooling Components Pages 812. . . . . . . . . . . . . . . . . . . . . . . . . .
III-ELECTRICAL CONNECTIONS Page 12. . . . . . . . . . . . . . . . . . . . . .
IV- PLACEMENT AND INSTALLATION Page 12. . . . . . . . . . . . . . . .
V- START UP - OPERATION Page 12. . . . . . . . . . . . . . . . . . . . . . . . .
Preliminary Checks Page 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling / Heating Start Up Page 12. . . . . . . . . . . . . . . . . . . . . . . . .
Safety or Emergency Shut Down Page 12. . . . . . . . . . . . . . . . .
VI- COOLING SYSTEM CHECKS Page 13. . . . . . . . . . . . . . . . . . . . .
Gauge Manifold Attachment Page 13. . . . . . . . . . . . . . . . . . . . . . .
Charging Page 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII-INDOOR BLOWER OPERATION / ADJUSTMENT
Pages 1314. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Operation Page 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Determining Unit CFM Pages 1314. . . . . . . . . . . . . . . . . . . . . . . .
Blower Belt Adjustment Page 14. . . . . . . . . . . . . . . . . . . . . . . . . . .
VIII- MAINTENANCE Pages 1415. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filters Page 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubrication Page 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply Air Blower Wheel Page 15. . . . . . . . . . . . . . . . . . . . . . . . . .
Evaporator and Condenser Coil Page 15. . . . . . . . . . . . . . . . . . . .
Electrical Page 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IX- GAS HEAT Pages 1620. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating Control Box Components Pages 1618. . . . . . . . . . . . .
Heat Exchanger Page 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Burner Assembly Page 18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heating Components Pages 1920. . . . . . . . . . . . . . . . . . . . . . . .
X-HEATING SYSTEM SERVICE CHECKS Pages 2023. . . . . . . . . .
A.G.A. / C.G.A. Requirements Pages 20. . . . . . . . . . . . . . . . . . .
Gas Piping / Testing Pages 21. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manifold Pressure Pages 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gas Flow / Gas Valve / Burner Page 22. . . . . . . . . . . . . . . . . . . .
Heat Exchanger Pages 2223. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition / Spark Eloctrode / Flame Sensing Page 23. . . . . . . . . .
Combustion Air Blower Page 23. . . . . . . . . . . . . . . . . . . . . . . . . . .
XI-ACCESSORIES Pages 2431. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RMF16 Roof Mounting Frame Page 24. . . . . . . . . . . . . . . . . . . . .
OAD24 Outdoor Air Damper Page 24. . . . . . . . . . . . . . . . . . . . . .
Economizers Pages 2427. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transitions and Supply / Return Diffusers Page 27. . . . . . . . . . .
Optional Cold Weather Kit Page 28. . . . . . . . . . . . . . . . . . . . . . . .
Firestats Page 28. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cycle Control Kit Pages 2829. . . . . . . . . . . . . . . . . . . . . . . . . . .
Status Panels Pages 2930. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commercial Controls Hardware Page 30. . . . . . . . . . . . . . . . . . .
Optional Commercial Controls Systems Pages 3031. . . . . . . .
XII- WIRING DIAGRAMS / OPERATION SEQUENCE
Pages 3239. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Unit Operation Sequence Pages 3235. . . . . . . . . . . . . . .
REMD16M Economizer Operation Sequence Pages 3639. . .
Warm Up Kit Operation Sequence Pages 38-39. . . . . . . . . . . . .