Individual Room Control Applications - Honeywell AUTOMATIC CONTROL SI Edition Engineering Manual

Individual Room Control Applications

Introduction
Unitar y Equipment Contr
ENGINEERING MANUAL OF AUTOMATIC CONTROL
ENGINEERING MANUAL OF AUTOMATIC CONTROL
............................................................................................................ 397
Graphic Symbols ................................................................................. 398
Abbreviations ....................................................................................... 399
Air Terminal Unit Control ..................................................................... 399
Variable Air Volume ATU ...................................................................... 399
Pressure-Dependent and Pressure-Independent ATU ................... 399
Single-Duct VAV ATU ...................................................................... 400
System Configuration ................................................................. 400
Throttling VAV ATU ..................................................................... 400
Variable Air Volume ATU ............................................................. 401
Variable Air Volume ATU with Electric Reheat ............................ 402
Constant Air Volume ATUs .......................................................... 402
Induction VAV ATU ...................................................................... 402
Parallel Fan ATU ......................................................................... 404
Series Fan ATU ........................................................................... 404
Dual-Duct ATU ................................................................................ 406
Dual Duct Pressure Independent VAV ATU ................................ 406
Dual Duct Pressure Independent Constant Volume ATU ............ 407
ol ............................................................................................................ 408
General ................................................................................................ 408
Natural Convection Units ..................................................................... 408
Radiant Panels .................................................................................... 409
Unit Heaters ........................................................................................ 409
General ........................................................................................... 409
Control ............................................................................................ 410
Two-Position Control ................................................................... 410
Modulating Control ...................................................................... 410
Down-Blow Unit Heater ................................................................... 410
Gas- or Oil-Fired Unit Heater .......................................................... 411
Unit Ventilators .................................................................................... 411
General ........................................................................................... 411
Control ............................................................................................ 412
ASHRAE Control Cycles ............................................................. 412
Standby/Warmup Stage ......................................................... 412
Cycle I-Fixed Maximum Percentage of Outdoor Air ............... 413
Cycle II-Fixed Minimum Percentage of Outdoor Air ............... 413
Cycle III-Variable Outdoor Air ................................................ 414
Day/Night Setback Control ......................................................... 414
Unit Ventilator Digital Control ...................................................... 415
Precautions and Conditions for Successful Operation .................... 418
Blocked Airflow ........................................................................... 418
Power Failure .............................................................................. 418
Coil Freeze-Up ............................................................................ 418
INDIVIDUAL ROOM CONTROL APPLICATIONS
395
CONTENTS