User Manual

Siemens Industry, Inc.

Application Note, App 14900

140-1231

2020-02-11

Table of Contents

Overview ................................................................................................................................... 6

BACnet ................................................................................................................................. 6

Hardware Inputs ................................................................................................................... 7

Hardware Outputs................................................................................................................. 7

I/O Mix (Relay Assignment Matrix) ....................................................................................... 8

Connection Diagram ............................................................................................................. 9

Ordering Notes ..................................................................................................................... 9

Sequence of Operation ......................................................................................................... 10

Control Temperature Setpoints .......................................................................................... 10

Effective Room Temperature .............................................................................................. 11

Heating/Cooling Switchover ............................................................................................... 11

Staging Control ................................................................................................................... 12

Compressor Operation ....................................................................................................... 12

Electric Heat (Optional) ...................................................................................................... 13

Gas Furnace (Optional) ...................................................................................................... 14

Operation Diagram – RTU with Three Cooling Stages and Three Heating Stages. .......... 15

Fan Operation ..................................................................................................................... 15

Wiring Diagram ................................................................................................................... 16

Auxiliary Sequences ........................................................................................................... 17

Humidification ................................................................................................................ 17

Dehumidification ............................................................................................................ 18

Occupancy Notification ....................................................................................................... 19

Economizer Enable ....................................................................................................... 20

Pre-Purge ...................................................................................................................... 20

Semi-Continuous Fan .................................................................................................... 20

Air Quality Management ..................................................................................................... 21

Service and Fault Messages ................................................................................................. 22

Sensor Failure Handling ..................................................................................................... 22

I/O Test Mode ..................................................................................................................... 22

Overcurrent Protection ....................................................................................................... 23

BACnet Scheduler ................................................................................................................. 24

Application 14900 Point Database ....................................................................................... 25

Scheduling Examples ............................................................................................................ 42