Random Start; Zone Temperature Control; Occupancy Modes; Occupied Mode - Trane Tracer ZN511 Installation And Operation Manual

Chapter 5 Sequence of operations for the heat pump configuration
26

Random start

Random start is intended to prevent all units in a building from energiz-
ing major loads at the same time. The random-start timer delays the fan
and compressor start-up from 5 to 30 seconds. If neither heating nor cool-
ing is initiated, or if fan operation is not required during the delay, the
random-start timer is allowed to time-out.

Zone temperature control

The Tracer ZN511 zone controller calculates a required heating or cooling
capacity (0–100%) according to the measured zone temperature and the
active temperature set point, and sequences the heat pump heating and
cooling stages accordingly. The active temperature set point is deter-
mined by the current operating modes, which include occupancy mode
and heat/cool mode.

Occupancy modes

Occupancy modes can be controlled by any of the following:
The state of the local (hardwired) occupancy binary input BI3 (see
•
"BI3: Occupancy or generic binary input" on page 15)
A timed override request from a Trane zone sensor (see "Timed over-
•
ride control" on page 28)
A communicated signal from a peer device (see "Peer-to-peer (master/
•
slave) data sharing" on page 30)
A communicated signal from a BAS
•
A communicated request, either from a BAS or a peer controller, takes
precedence over local requests. If a communicated occupancy request has
been established and is no longer present, the controller reverts to the
default (occupied) occupancy mode after 15 minutes (if no hardwired occu-
pancy request exists). The Tracer ZN511 has the following occupancy
mode options:
Occupied
•
Unoccupied
•
• Occupied standby
• Occupied bypass

Occupied mode

In occupied mode, the controller maintains the zone temperature based
on the occupied heating or cooling set points. The controller uses the occu-
pied mode as a default mode when other forms of occupancy request are
not present. The fan will run as configured (continuous or cycling with
compressor operation). The outdoor air damper will close when the fan is
off. The temperature set points can be local (hardwired), communicated,
or stored default values (configurable in Rover).
CNT-SVX06B-EN