Orion System SA Controller - Manual (Page 29)

SA Controller Operator Interface
Programming
29
Setpoint Screen #13 - Dehumidifi cation Indoor
RH & Entering Air Dewpoint
SA Unit Spts ID 102
Dehumidification Spt
Indoor RH....: 50%
Entering Dp..: 55ºF
On VAV confi gured units that are not using 100% Outdoor Air, when the
Indoor Relative Humidity percentage rises above the Indoor RH Setpoint,
the unit will start operating in Dehumidifi cation Mode.
If an Indoor Humidity Sensor is installed, the unit will reset the Coil
Suction Temperature Setpoint as needed to maintain this Indoor RH
Setpoint. This includes VAV, CAV, and MUA applications.
On MUA confi gured units that are using 100% Outdoor Air, when the
Outdoor Air Dewpoint Temperature rises above the OA Dewpoint Set-
point, the unit will start operating in Dehumidifi cation Mode.
Description Minimum Default Maximum
Dehumidifi cation Setpoint
Indoor RH
1% 50% 100%
Dehumidifi cation Setpoint
OA Dewpoint
35ºF 55ºF 80ºF
Setpoint Screen #14 - Dehumidifi cation Coil
Temperature
SA Unit Spts ID 102
Dehumidification
Coil Temperature
Setpoint.....: 45ºF
During the Dehumidifi cation Mode, the SA Controller uses the calculated
Coil Temperature to activate DX Cooling based on this Dehumidifi cation
Coil Temperature Setpoint. The SA Controller uses a Suction Pressure
Transducer to read Suction Pressure (the Saturation Vapor Pressure of
the Refrigerant) and converts this Suction Pressure reading to a Coil
Temperature value. This calculation is based on using R410A refriger-
ant only and will not work with any other refrigerant. This setpoint
determines the number of compressor stages that need to be activated
to maintain the Dehumidifi cation Coil Temperature Setpoint.
Description Minimum Default Maximum
Dehumidifi cation Coil
Temperature Setpoint 35ºF 45ºF 70ºF
SA Controller Setpoint Screens
Setpoint Screen #15 - Cooling Head Pressure
Setpoint
SA Unit Spts ID 102
Cooling
Head Pressure
Setpoint: 275PSI
If you are using the Head Pressure Module, this is the Cooling Setpoint
for control of the condenser fan speed. This is based on the highest
head pressure reading of up to 4 Head Pressure Sensors. See the Two
Condenser Head Pressure Module Technical Guide for detailed infor-
mation.
Description Minimum Default Maximum
Cooling Head Pressure
Setpoint
250 PSI 291 PSI 400 PSI
Setpoint Screen #16 - Reheat Head Pressure
Setpoint
SA Unit Spts ID 102
Reheat
Head Pressure
Setpoint: 375PSI
If you are using the Head Pressure Module, this is the Reheat Setpoint
for control of the condenser fan speed during dehumidifi cation. This is
based on the highest head pressure reading of up to 4 Head Pressure
Sensors. See the Two Condenser Head Pressure Module Technical Guide
for detailed information.
Description Minimum Default Maximum
Reheat Head Pressure
Setpoint
250 PSI 395 PSI 400 PSI