Trane BCHC, BCVC manual Fan Mode Operation Rotating Components, Tracer ZN520 fan configuration

Start-Up

heating capacity of the unit (0–100%). The outputs are controlled based on the unit configuration and the required heating capacity.

Fan Mode Operation

WARNING

Rotating Components!

Disconnect all electric power, including remote disconnects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to disconnect power before servicing could result in death or serious injury.

For multiple fan speed applications, the Tracer™ ZN controller offers additional fan configuration flexibility. See Table 19 for fan operation sequences. Separate default fan speeds for heating and cooling modes can be configured using Rover™ service software.

Table 19. Tracer ZN520 fan configuration

	Auto fan operation	Fan speed default
Heating	Continuous	Off
		Low
		High
Cooling	Continuous	Off
		Low
		High

The fan runs continuously at selected speeds, high or low. When the fan mode switch is in the auto position or a hardwired fan mode input does not exist, the fan operates at the default configured speed. See Table 20 for Tracer™ ZN520 default fan configuration for heating and cooling modes. During unoccupied mode, the fan cycles between high speed and off with heating and cooling fan modes. If the requested speed is off, the fan always remains off.

Table 20. Fan sequence of operation

Fan speed	Tracer™ ZN controller	Sequence of operation
Off	ZN010, ZN510, ZN520	• fan is off
		• control valves and damper option are closed
		• low air temperature detection open is still active
Low or high (continuous fan) ZN010, ZN510		• fan operates continuously at selected speed
		• 2-position control valve option cycle as needed
		• 2-position control valve option opens to an adjustable mechanical stop-position
Low or high (continuous fan) ZN520		• fan operates continuously at selected speed
		• modulating control valve option cycles as needed
Auto (cycling)	ZN010, ZN510	• fan, 2-position damper cycle, and control valve cycle as needed
		• in cooling mode, fan cycles from off to high
		• in heating mode, fan cycles from off to low
		• when heating/cooling is not required, the fan is off and the 2-position damper
		option closes
Auto	ZN520	• fan cycles between high and medium, and never turns off unless the controller is
		in unoccupied mode

• modulating or 2-position control open to maintain setpoint

During dehumidification, when the fan is in auto, the fan speed can switch depending on the error. The fan speed increases as the space temperature rises above the active cooling setpoint.

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