CCP Supply temperature Sensor Failure, displays -40 degrees

Issue:

CCP Supply temperature Sensor Failure, displays -40 degrees

Resolution:

Issue: If supply air value displayed at the CCP touch screen sensor shows -40 degrees but CCP continues to run and does not go into priority shutdown.

This problem occurs is Voyager type is a commercial Voyager in CV mode. A Voyager is configured as a 'Commercial Voyager' using J3 Plug on the RTOM options module. A jumper between J3-1 and J3-5 makes Voyager a commercial Voyager). If CCP is talking to Commercial Voyager, the CCP tries but fails to read supply temperature wired to the RTOM module. Cut jumper between J3-1 and J3-5 on Plug 3 (J3) of the RTOM, cycle power on the Voyager, and supply temperature wired to the communicating bypass is read , and Voyager instead of Voyager commercial appears as a the unit type in the CCP.
The CCP will control staging of the compressors. If the Voyager II had dehumdification option, this will not work with this configuration.

This will work on 27.5, 30, and 35 ton unit as they are 2 stage compressor units. You should not do this on 40 and 50 ton units as these have three stage compressor operation and the CCP will only have two stage control.

Note: If SA sensor failure appears in diagnostics on the operator display and PC software. A shorted or open temperature sensor or failed communicating sensor/bypass control is the cause.

 

Other Question/Problem/Cause Statements:

• Why does supply air temperature display -40 degrees at the CCP?
• CCP runs but displays a supply temperature of -40 degrees.
• Replaced supply air sensor at the communicating bypass damper assy but displayed temperature still display -40

Facts:

• Varitrac CCP III with communicating bypass unit
• VariTrac III Central Control Panel (CCP)

Original wave: wave49539