Voyager economizer and mechanical cooling stages

Issue:

Voyager economizer and mechanical cooling stages

Resolution:

The CCP enables Voyager cooling and tries to maintain a supply air cooling setpoint. Voyager economizer becomes the 1st stage of cooling if outdoor air conditions are acceptable. If outdoor conditions are unacceptable, mechanical cooling becomes 1st stage of cooling and is cycled on and off as if no economizer existed.

A Voyager in economizing mode (OA temperature below economizing setpoint) modulates its damper to maintain the supply air cooling setpoint (set at the CCP). If the zone temperature is recovering adequately with only the economizer(0.2 F./minute), mechanical cooling is not used. If the economizer modulates to 100%, and 3 minutes passes and the zone temperature is not dropping fast enough (0.2 F./minute), a compressor turns "ON" to assist the economizer. If available and requires a second stage of mechanical cooling is turned on maintain setpoint. The economizer continues to function as 1st stage of cooling as long as OA temperature is below economizing setpoint.

If the unit is a single-stage on a CCP (II or III), it will not bring on mechanical cooling during economizing. Add the jumper that will tell the unit it has two stages of cooling. Contact Clarksville for the jumper location.

 

Other Question/Problem/Cause Statements:

• Voyager economizer and mechanical cooling stages.
• When a CCP is connected to a Reliatel 3-25 ton RTU, and the CCP sends a cool command to the RTU, and the outdoor air is good to economize, what determines whether or not the RTU continues to economize or the DX starts ?

Facts:

• VariTrac III Central Control Panel (CCP)

Original wave: wave8069