52 BCXC-SVX01B-EN
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 Tab le 19 for fan operation sequences. Separate default fan speeds for heating and
cooling modes can be configured using Rover™ service software.
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 2 0 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.
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.
Table 19. Tracer ZN520 fan configuration
Auto fan operation Fan speed default
Heating Continuous Off
Low
High
Cooling Continuous Off
Low
High
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
