Calibrating VariTrane Boxes on a VariTrac CCP panel

Issue:

Calibrating VariTrane Boxes on a VariTrac CCP panel

Resolution:

Issue:
I am assuming we are talking about a VariTrac II CCP with Summit and VariTrane VAV boxes.

Discussion:
When CCP goes from Occupied to Unoccupied it goes through a calibration process for the supply air static pressure sensor. During this process it sends a Drive Open command to the boxes for 3 minutes, and a then Drive to Max command to the boxes. Once the fan has started it waits for the bypass to close and all the boxes to achieve Max, and then it take the reference static pressure reading for the CCP. It does not send a RESET command to the UCMs during this process, so they do not calibrate for zero flow during the daily CCP calibration.

Solution:
One option is to cycle power to the VAV UCMs to force calibration. 20 minutes after a power failure the UCMs will do a calibration themselves, staggered by their address so they don't all go closed at once. Cycling power to the CCP at the same time will cut down on the alarms you get.

Note: Just as a point of information, the new CCP3 actually does send a reset command to the VAV UCM every day when it goes through system calibration. CCPIII is not compatible with Tracer Summit, however CCPII is.

 

Other Question/Problem/Cause Statements:

• Calibrating VariTrane Boxes on a VariTrac CCP panel

Facts:

• VariTrac II Central Control Panel (CCP)
• VariTrac III Central Control Panel (CCP)

Original wave: case3906