Trane ACONT900AC43UA Service Manual page 103

Communicating Air Handler
Section A
Introduction ............................................................................................................................................... 2
Air Handler Interface Display Assembly ................................................................................................ 2
24VAC Fuse ......................................................................................................................................... 2
Control Board ............................................................................................................................................ 3
Serial Port Variable Speed Motor .......................................................................................................... 3
Electric Heater Terminals ...................................................................................................................... 3
Humidifier Terminals - (HUM)................................................................................................................. 3
Electronic Air Cleaner Terminals (EAC) ................................................................................................. 3
Status LED ........................................................................................................................................... 3
Bit Master (BM) LED ............................................................................................................................ 4
COM LED ............................................................................................................................................. 4
Fault LED ............................................................................................................................................. 4
Sequence of Operation ............................................................................................................................. 5
Communicating Mode ........................................................................................................................... 5
Continuous Fan .............................................................................................................................. 5
Call for Cooling ............................................................................................................................... 5
Call for 2nd Stage Cooling ............................................................................................................. 5
Heating .......................................................................................................................................... 5
Heat Pump Only Applications ......................................................................................................... 5
Heat Pump & Electric Heat Applications ........................................................................................ 6
24V Mode ............................................................................................................................................ 6
Continuous Fan .............................................................................................................................. 6
Cooling Operation ........................................................................................................................... 6
Blower Operation vs. Y1 & Y2 Inputs - A/C & Heat Pumps ............................................................. 6
Heating Operation .......................................................................................................................... 6
Electric Heat Only Sequence - 24VAC Input .................................................................................. 7
Heat Pump Only Sequence - 24VAC Input ..................................................................................... 7
Heat Pump with Electric Heat Sequence - 24VAC Inputs .............................................................. 7
Test Mode .......................................................................................................................................... 7
Communicating Systems Troubleshooting Checklist ............................................................................. 8
Service Bulletins ....................................................................................................................................... 9
ACC-SVB14A-EN (Communicating Air Handler with
PWM from (A/T)CONT402 and Residential Zoning Systems) ................................................................ 9
SSA-SVB09A-EN (Control Board Replacement) .................................................................................. 11
Air Handler
AH - A 1