Pre-Cool (Morning Cool Down) - Trane Tracer VV550 Installation, Operation And Maintenance Manual

Sequence of Operations
Table 32.Controller operation during morning warm-up (continued)
Primary air temperature
Warm air in duct:
Configured auto-changeover
setpoint < primary air
a
temperature < configured
reheat enable setpoint minus
b
5°F
Hot air in duct:
Primary air temperature
greater than configured reheat
b
enable setpoint
a. Primary air temperature is derived from either communicated Source Temperature, or the Primary/Discharge air temperature sensor
when this input is configured for primary air temperature.
b. The Rover™ service tool checks the range of the configured reheat enable setpoint: 70°F to 100°F (21.11°C to 37.78°C) for electric
heat; and 70°F to 200°F (21.11°C to 93.33°C) for hot water heat.

Pre-cool (Morning Cool Down)

The controller enters pre-cool on receipt of a communicated command. This is the only
way morning pre-cool can be activated. The controller remains in pre-cool until the
command is changed. This operational sequence is also used for night purge.
Pre-cool uses the occupied cooling setpoint regardless of the occupancy mode. All
ventilation requirements are waived during pre-cool.
operation during pre-cool.
Table 33.Controller operation during pre-cool
Primary air temperature
Cold air in duct:
Primary air temperature less than
configured auto-changeover
setpoint minus 10°F
Warm air in duct:
Configured auto-changeover
setpoint < primary air temperature
Hot air in duct:
Configured reheat enable setpoint <
primary air temperature
a. Primary air temperature is derived from either communicated source temperature, or the primary/discharge air temperature
sensor when configured for primary air temperature.
50
Space temperature
< Active heating
setpoint
< Active heating
setpoint
> Active heating
setpoint plus 0.5°F
< Active heating
setpoint
a
> Active heating
setpoint plus 0.5°F
a
Space
temperature
< Active cooling
setpoint minus
2°F
> Active cooling
setpoint
Do not care
Do not care
Primary airflow
control Fan control
Normal control, Series On
modulate from Parallel Off
heat min to max
Normal control, Series On
modulate from Parallel On (w/
heat min to max reheat)
Heat min Series On Parallel
Off
Normal control, Series On
modulate from Parallel Off
heat min to max
Heat min Series On
Parallel Off
Table 33
Primary airflow Fan control
control
Cool min Series On
Parallel Off
Normal control, Series On
modulate cool min Parallel Off
to max
Heat min Series On
Parallel Off
Heat min Series On
Parallel Off
Reheat control
Reheat Not
Present
Reheat On (All
stages on)
Reheat Off
Reheat Off
Reheat Off
shows controller
Reheat control
Reheat Off
Reheat Off
Reheat Off
Reheat Off
CNT-SVX17G-EN