Issue:
How do you control the spare binary output on the Varitrac III CCP optional relay board?
Resolution:
Here's the answer from VAV-SVU01A-EN, page 18
Spare Binary Output Control
The sixth binary output on the optional relay board is an SPDT unpowered spare output relay. An entry in the PC software allows you to choose how the relay is controlled:
- Ventilation The spare output controls the outdoor air damper control. The output is energized when the CCP (all groups) is unoccupied. When the first group becomes occupied, the CCP enters the morning warm-up/precool mode and the spare output remains energized. The mode terminates when half of the occupied voting zones are satisfied or become opposite callers. Morning warmup also terminates after two hours or if the systems heat/cool mode changes over. The spare output is de-energized when morning warm-up terminates.
- H/C The spare output is energized when the CCP is in cooling and de-energized when it is in heating.
- ICS The state of the relay is controlled by an upper-level system, such as Tracker or Tracer (currently not supported).
- CO2 The relay is controlled by the CCP demand-controlled ventilation program and energizes when the CO2 alarm point is reached. This relay function can be used to reset the position of a ventilation damper on a noncommunicating HVAC unit based on the zone CO2 level.
The relay board does not offer true economizer control. The damper control is either open or closed. For economizing, you could use the relay to turn on and off or occupied and unoccupied a ZN517 that controls the rooftop.
Other Question/Problem/Cause Statements:
-
How do you control the spare binary output on the Varitrac III CCP optional relay board?
- Can I use the CCP relay board to control a generic rooftop economizer?
Facts:
- VariTrac III Central Control Panel (CCP)
- Generic binary output
Original wave: wave1116
Document Identifier: DOC-78651
Document Identifier: 78651