Trane BCVC, BCHC manual Start-Up Fan Cycling Operation, Fan Off Delay, Fan Start on High Speed

Start-Up

Fan Cycling Operation

Tracer™ ZN520 does not support fan cycling in occupied mode. The fan cycles between high speed and off in the unoccupied mode only. The controller’s cascade control algorithm requires continuous fan operation in the occupied mode.

Fan Off Delay

When a heating output is controlled off, the Tracer™ ZN controller automatically holds the fan on for an additional 30 seconds. This 30-second delay allows the fan to blow off any residual heat from the heating source, such as a steam coil. When the unit is heating, the fan off delay is normally applied to control the fan; otherwise, the fan off delay does not apply.

Fan Start on High Speed

On a transition from off to any other fan speed, the Tracer™ ZN controller automatically starts the fan on high speed and runs the fan at high speed for 0.5 seconds. This provides ample torque required to start all fan motors from the off position.

Fan Operation During Occupied Heating Modes

The ZN520 fan output(s) normally run continuously during the occupied and occupied standby modes, but cycle between high and off speeds with heating/cooling during the unoccupied mode. When in the occupied mode or occupied standby mode and the fan speed is set at the high or low position, the fan runs continuously at the selected speed. Refer to “Troubleshooting,” p. 72 for more information on abnormal fan operation.

Table 21. Fan mode operation, Tracer ZN010 and ZN510

	Heating mode		Cooling mode
Fan mode	Occupied	Unoccupied	Occupied	Unoccupied
Off	Off	Off	Off	Off
Low	Low	Off/high(a)	Low	Off/high(a)
High	High	Off/high(a)	High	Off/high(a)
Auto continuous	Heat default	Off/high(a)	Cool default	Off/high(a)
Cycling off	Off/heat default(a)	Off/high(a)	Off/cool default(a)	Off/high(a)

Notes:

1.During the transition from off to any fan speed but high, Tracer™ ZN010 and ZN510 automatically start the fan on high speed and run for one-half of a second before transitioning to the selected speed (if it is other than high). This provides enough torque to start all fan motors from the off position.

2.When the heating output is controlled off, ZN010 and ZN510 automatically control the fan on for an additional 30 seconds. This delay allows the fan to dissipate any residual heat from the heating source, such as electric heat.

(a)Whenever two states are listed for the fan, the first state (off) applies when there is not a call for heating or cooling. The second state (varies) applies where there is a call for heating or cooling. The heat default is factory-configured for low fan speed, and the cool default is high.

Table 22. Valid operating range and factor default setpoints, Tracer ZN010 and ZN510

Setpoint/parameter	Default setting	Valid operating range
Unoccupied cooling setpoint	85°F	40°F–115°F
Occupied cooling setpoint	74°F	40°F–115°F
Occupied heating setpoint	71°F	40°F–115°F
Unoccupied heating setpoint	60°F	40°F–115°F
Cooling setpoint high limit	110°F	40°F–115°F
Cooling setpoint low limit	40°F	40°F–115°F
Heating setpoint high limit	105°F	40°F–115°F
Heating setpoint low limit	40°F	40°F–115°F
Power up control wait	0 sec	0 sec–240 sec

54 BCXC-SVX01B-EN