Varitrac CCP III does not display cooling high limit or heating low limit for VAV UCM IIs at version 2.0 or 2.1 on the comm4 link.

 

Issue:

Varitrac CCP III does not display cooling high limit or heating low limit for VAV UCM IIs at version 2.0 or 2.1 on the comm4 link.

Resolution:

A Varitrac CCP III when connected to VAV UCM IIs at either version 2.0 or 2.1 display a zero (-0.0) value for the occupied cooling high limit and heating low limit value. They cannot be changed either from the UCM edit screen on Varitrac or through Rover service tool because those limit locations do not exist in the controller. The fix is to replace the UCM controller with a 4.2 version.

Notes:

 

Changes:

 

Other Question/Problem/Cause Statements:

• Why do cooling high limit and heating low limit values display as -0.0 in edit fields?
  Cannot change cooling high limit and heating low limit setpoint values from CCP or Tracker panel or with Rover.
• Why don't cooling high limit or heating low limit appear on Varitrac CCP III touch screen?

Facts:

• Comfort Managers installed between 1992 and 1993
  CCP III upgrade of existing Comfort Manager with UCM II
• VariTrac III Central Control Panel (CCP)

Original wave: wave41572