Chapter 2
and dampers: status switches, differential pressure switches, airflow paddle switches,
Status switches at fans and dampers monitor the operation of the devices. Multiple binary inputs at the Tracer MP581s verify the On and Off status of fans and the Open and Closed status of dampers. If a status switch does not confirm the commanded (automatic or manual) operation, a Fail indicator activates at the FSCS. Failure detection must incorporate a time delay to give the devices time to function.
Differential pressure switches, airflow paddle switches, and current- sensing relays monitor fan operations. Differential switches piped across fan and paddle switches in the air stream can give erroneous indications.
IMPORTANT
A
Limit switches and end switches monitor dampers. The switches activate damper Open and Closed signals for the FSCS. The damper blades activate the switches. Some codes require two switches in order to sense both the fully opened and fully closed position of the damper.
Tracer MP581 programmable controller
The Tracer MP581 must have multiple binary inputs to verify the On and Off operation of fans. It must also have multiple binary inputs to verify the Open and Closed positions of dampers.
Equipment supervision
Equipment supervision is a
Confirming communications among all system control panels is a supervision technique that monitors basic system integrity. If any panel loses its communications, a Trouble alert is sent to the FSCS.
Normal use operations confirm the integrity of field point wiring for nondedicated equipment. Nondedicated equipment provides conditioned air to the building daily. When nondedicated equipment is not operational, comfort conditions deteriorate and building tenants notify maintenance personnel.
26 |
