During the construction phase of a project, the zone dampers may not be fully functional or installed. Under normal operation, the system shuts down the RTU if zone controllers are offline or if the bypass damper is offline. In this case, you can request RTU heating or cooling even though the system is not yet fully installed. Construction mode ignores offline conditions and allows the RTU to run heating or cooling.
The system can be placed in Heat, Cool, Fan Only, or Not In Use operating states.
- In a Heat state, the RTU adjusts the SAT to meet the discharge heating setpoint. The economizer remains at the minimum position.
- In a Cool state, the RTU adjusts the SAT to meet the discharge cooling setpoint. The economizer modulates if conditions allow.
- In a Fan Only state, the supply fan runs, and heating and cooling is off. The economizer remains at the minimum position.
- In a Not In Use state, the Verasys system and economizer operate normally.
When the system is in construction mode, it ignores the following conditions that initiate a system shutdown:
- All zone controllers are offline.
- The bypass controller is offline.
- No voting zones are on the system.
The system still enters shutdown mode during construction mode if the SAT is unreliable or if the system is shut down via the VZC from the SBH.
Construction mode does not depend on occupancy. The operation is identical when the system is occupied or unoccupied.