When you go to the advanced overrides page for a Voyager Rooftop Unit in addition to Present Value, the following fields can be overridden:
In this field you can lock out all compressors on the Voyager. By locking out the compressors, a non-heat pump Voyager will not be able to provide any mechanical cooling. If the compressors are locked out on a heat pump unit, the Voyager will not be able to provide cooling or heating from the compressors. Even though the Voyager compressor does not require an external ambient lockout, you could use this field to lockout the compressors when the outdoor air temperature falls below a certain value.
Note: This field has no effect on the economizer control; only compressor cooling is affected.
This field allows you to limit the number of stages of mechanical cooling that will be allowed to operate in the Voyager. This field may be used in a demand-limiting control strategy that limits the stages of compressors operating during periods of high electrical demand.
Note: This field does not affect compressor operation during the heat mode for heat pump units.
This applies only to 27 ½ to 50 ton Voyagers. If communications to the Voyager are down, this field is still available for editing.
The field allows you to activate the Pressurization Mode on the Voyager unit. The Pressurization Mode introduces as much outdoor air as possible to the conditioned space without providing a means for exhausting air, which can result in a positive static pressure condition in the space.
During the Pressurization Mode, the supply fan is turned on, inlet guide vanes (or VFD) are driven open, the exhaust fan is turned off, the outside air damper is driven open, and all heating and cooling is disabled.
If multiple ventilation override modes are activated simultaneously, the pressurization mode has the highest priority and the purge mode has the lowest priority.
The ventilation override modes can be used in situations requiring the Voyager rooftop units to assist in coordinated air movement control across several zones or floors.
This applies only to 27 ½ to 50 ton Voyagers. If communications to the Voyager are down, you can still edit in this field.
This field allows you to activate the exhaust mode on the Voyager unit. The Exhaust Mode is used to discharge existing air from the conditioned space without providing a means for replacement air, which can result in a negative static pressure condition in the space.
During the Exhaust Mode, the supply fan is turned off, the inlet guide vanes (or VFD) are closed, the exhaust fan is turned on (if the unit is equipped with an exhaust fan), the outside air damper is closed, and all heating and cooling is disabled.
If multiple ventilation override modes are activated simultaneously, the pressurization mode has the highest priority and the purge mode has the lowest priority.
Ventilation override modes can be used in situations requiring the rooftop units to assist in coordinated air movement control across several zones or floors.
This field allows you to activate the Purge Mode on the Voyager unit. The Purge Mode is most often used to “change” the air in the conditioned space in an effort to improve the indoor air quality.
During the purge mode the supply fan is turned on, the inlet guide vanes (or VFD) if installed, control to the static pressure setpoint, the exhaust fan is controlled normally, the outside air damper is driven open, and all cooling is disabled. The unit’s heating capacity remains enabled during the Purge Mode. If multiple ventilation override modes are activated simultaneously, the pressurization mode has the highest priority and the Purge Mode has the lowest priority.
Ventilation override modes can be used in situations requiring the rooftop units to assist in coordinated air movement control across several zones or floors.
Use this field to override control of the economizer damper and drive the damper to the fully closed position. This field might be used to drive the economizer closed during times of extremely poor outdoor air quality to prevent the conditioned space from receiving the bad air.
This field allows you to disable all heating capacity on the Voyager.
In the emergency heat mode, the unit locks out compressors and only uses auxiliary electric heat to maintain the conditioned space at the zone heating setpoint.
This field will only be available if the unit is a heat pump option, and the Heat/Cool Control Source is set to Tracer.
Note: This field is available only when the unit is a heat pump.
Prevent the electric heat strips from operating.
If the Voyager rooftop is not communicating with the BCU when the Overrides screen is opened, the Service Test field group will be unavailable.
Test Mode
You can place the Voyager into the service test mode by choosing a test mode in this box. Use the service test mode during job startup and commissioning, and as a tool for diagnosing unit problems. When you select a service test mode, all standard unit operations cease and the Voyager is placed into the selected test mode.
Because the service test mode is not intended for use over extended periods of time, there is a timer that will disable the service test mode after 15 minutes. Each time you change the test mode, the 15-minute timer resets.
The Test Modes that are available will be specific to the type of Voyager unit that is connected: heat pump, 3 - 25 ton constant volume, 27.5 – 50 constant volume, or VAV units.
Status
This field displays the test mode status. Status information is automatically refreshed every 10 seconds. When the Voyager is not in a service test mode, this message displays: “No test in progress.”
Start
Initiate a service test.
Stop
Cancel a service test.