What does priority local heat do?

Issue:

What does priority local heat do?

Resolution:

When enabled the VAV uses local heat as first stage of heating.  When edited to no, the UCM does not use the reheat until the space temp is degrees below the heating setpoint.

This can also affect zone voting for changeover.  When priority local heat is "on", and the zone has local heat, the zone becomes a heat caller when the zone temperature is 2 degrees below the active heating setpoint.  It becomes a no caller when zone temperature rises to 1.5 degrees below the active heating setpoint.  When priority local heat is "on", and the zone has local heat, the zone becomes a strong heat caller when the zone temperature is 3 degrees below the active heating setpoint.  It becomes a no caller when zone temperature rises to 2 degrees below the active heating setpoint. 

When priority local heat is "off", and the zone has local heat, a zone becomes a caller when the zone temperature is 1 degrees below the active heating setpoint.  It becomes a no caller when zone temperature rises to .5 degrees below the active heating setpoint.  This is the same as the behavior for zones that have no local heat.

 

Other Question/Problem/Cause Statements:

• What does priority local heat do?

Facts:

• VARITRAC II CENTRAL CONTROL PANEL (CCP)
• VariTrac II Central Control Panel (CCP)
• VariTrac III Central Control Panel (CCP)

Original wave: wave15939