CNT-SVX04A-EN
Sequence of operation
44
Power-up sequence
Manual output test can be initiated at any
time in the power-up sequence or during
normal operation.
When 24 VAC power is initially applied to the controller, the following sequence
occurs:
■
Green Status LED turns on.
■
All outputs are controlled Off.
■
The controller reads input values to determine initial values.
■
Stand-alone control is assumed unless occupancy data is communicated.
■
Random start timer expires (5 to 30 seconds, random).
■
Power-up control Wait feature is applied. When power-up control wait is
enabled, the controller waits 120 seconds to allow ample time for
communicated control data to arrive. If, after 120 seconds, the controller
does not receive a communicated occupancy request, the unit assumes
stand-alone operation.
■
All modulating valves and damper calibrate closed, face and bypass damper
calibrate to bypass (when present).
■
Normal operation begins after 290 (potentially) seconds have passed.
Manual output test can be initiated at any time
. Refer to the
Manual
output test
section on page 88.
Setpoint operation
The controller has three sets of possible heating and cooling setpoints:
In unoccupied mode, the controller always
uses locally stored default unoccupied
heating and cooling setpoints. These
setpoints are configured during factory
download and unit verification. Use Rover
service tool to modify these default
unoccupied setpoints.
■
Occupied
■
Occupied standby
■
Unoccupied
Setpoint selection
Internal and external setpoint adjustment
Zone sensors with an internal or external setpoint adjustment (1 k
Ω
) provide
the Tracer ZN.520 zone controller with a local setpoint (50 to 85°F or 10 to
29.4°C). The internal set point adjustment is concealed under the zone sensor’s
cover. To reveal the adjustable setpoint wheel, remove the zone sensor cover.
