Trane Tracer VV550 User Manual

70 CNT-SVX17G-EN
Sequence of Operations
Unoccupied Ventilation Flow Control
The controller closes the air valve. Local electric heat and hot water heat are disabled. The
hot water valves open if needed for freeze protection. The operation of freeze protection
for local hot water heat depends on whether the controller is operating as a network
controller or a stand-alone controller. Table 43 shows unoccupied VFC control freeze
prot
ect
ion for hot water reheat.
Table 43.Unoccupied VFC control, freeze protection for hot water reheat
Controller
operation
Air valve
position
Condition
Hot water valve
position
Networked and
val
id
communicated
source
temperature
Closed
no flow
Communicated source temperature greater than
co
nfigured outdoor air low limit
Closed
Communicated source temperatur
e less than or equal to
configured outdoor air low limit, freeze protection active
diagnostic (with 10°F hysteresis)
Open to 100%
Stand-alone coil
te
mperature
sensed at
discharge air
temperature
a
Closed
no flow
Discharge air temperature greater than configured
outdoor air low limit
Closed
Discharge air temperature less than or equal to configured
outdoor air
low limit, freeze protection active diagnostic
(with 10°F hysteresis)
Open to 100%
Fan Control
Ventilation control does not use the fan.
Flow Tracking Control Mode
Flow tracking control (FTC) is one of three supported control algorithms. Two Tracer®
VV550/VV551 controllers work together to provide flow tracking control (see Table 44).
The spa
ce temperature controller outputs the airflow (reported airflow). The space
temperature controller airflow output (reported airflow) is bound to the flow tracking
controller airflow setpoint input (communicated airflow setpoint). The flow tracking
controller adds the configured airflow tracking offset (positive or negative) to the airflow
setpoint (communicated airflow setpoint) and controls the airflow to this setpoint. The
flow tracking controller does not require a space temperature sensor or a discharge air
temperature sensor. For more information on flow tracking control and flow tracking
operation, refer to Table 63 on page 95.
a. Place the discharge temperature sensor in close proximity to the hot water coil discharge. The sensor effectively reports coil
temperature when there is no airflow through the coil. Therefore, the coil can be freeze protected by the discharge air
temperature sensor.

Trane Tracer VV550 Specifications

General

Brand	Trane
Model	Tracer VV550
Category	Controller
Language	English