Orion System SA E-BUS Controller - Manual (Page 44)

Zone
Zone
Sequence of Operations
SA E-BUS Controller Technical Guide
44
If the unit is confi gured for Variable Flow and has a
Water Side Economizer (WSE):
When compressor(s) are fi rst called to activate, the signal to the
Condenser Valve will go to 75% for 3 minutes in order to prove
water fl ow. During this period, the WSE Bypass Valve signal will
go to 100%. After this 3 minute period, the compressor(s) will en-
ergize, the Condenser Valve signal will go to 100%, and the WSE
Bypass Valve will modulate to maintain the Head Pressure Setpoint
(275 PSI adjustable). During Heat Pump Heating, the WSE Bypass
Valve signal will go to 100%.
Water Flow must always be initially proven for the compressors
to energize for Cooling, Dehumidifi cation, or Heat Pump Heating.
Once the compressor(s) are energized, the only time a loss of water
fl ow will be recognized during Cooling or Dehumidifi cation is if
the WSE Bypass Valve is above 70%. If this happens, an alarm will
be generated and the compressors(s) will be de-energized. During
Heat Pump Heating, anytime there is a loss of water fl ow, an alarm
will be generated and the compressors(s) will be de-energized.
When compressors are not active, the WSE Bypass Valve signal
will go to 100%. When the unit is off, the Economizer (WSE) Valve
and WSE Bypass Valve will be closed.
Economizer Flush Cycle
If the Economizer has been closed for 72 hours, a Flush Cycle will be
initiated the next time the compressor is activated or at the next 6:00 AM
time slot, whichever happens fi rst. During the Flush Cycle, the Econo-
mizer Valve will open for 5 minutes and then close again. The 72 hour
timer will restart once the Flush Cycle is completed or the Economizer
has been activated and has closed again.
Chilled Water Cooling
One Stage of Cooling needs to be confi gured for the Chilled Water
Valve. If the Water Side Economizer is active, the Economizer valve
needs to reach 100%, before activating the Chilled Water Valve. When
the Chilled Water Valve is active, the valve will modulate to maintain
the Active Supply Air Cooling Temperature Setpoint.
External Cooling
The SA E-BUS Controller can be confi gured to control stages of cooling
that are external to the SA Unit.
Dehumidifi cation Mode
On VAV or CAV applications, the Indoor Air Humidity initiates Dehu-
midifi cation when the Indoor Air Humidity rises 5% above the Indoor
Air Humidity Setpoint during the Occupied Mode of operation and
likewise stops Dehumidifi cation when the Indoor Air Humidity drops
more than 5% below the Indoor Air Humidity Setpoint during the Oc-
cupied Mode of operation.
On 100% Entering Air applications, the Entering Air Dewpoint initiates
the Dehumidifi cation Mode when the Entering Air Dewpoint rises 2
F
above the Entering Air Dewpoint Setpoint during the Occupied Mode
of operation and likewise stops Dehumidifi cation when the Entering Air
Dewpoint drops more than 2
F below the Entering Air Dewpoint Setpoint
during the Occupied Mode of operation. The Entering Air Dewpoint is
calculated by using an Entering Air Temperature Sensor and an Entering
Air Humidity Sensor.
For Chilled Water units, the SA E-BUS Controller opens the Chilled
Water Valve to a fi xed 100% position to provide full moisture removal
capabilities.
For DX Cooling Units, the SA E-BUS Controller will modulate the
Copeland Digital Scroll™ Compressor(s) and activate the Fixed Stages
as necessary to maintain the Evaporator Coil Temperature Setpoint. The
Evaporator Coil Temperature is calculated by using the Suction Pressure
Transducer and converting the pressure to temperature.
Coil Temperature Reset
Any time an Indoor Humidity Sensor is used, the Coil Temperature
Setpoint will be automatically reset as the humidity rises above or drops
below the Indoor Humidity Setpoint. It can reset the Coil Temperature
Setpoint by a maximum of 5ºF. For example, if the Coil Temperature
Setpoint is 45ºF and the Indoor Humidity Setpoint is 50% with an ac-
tual humidity reading of 55%, the new Coil Temperature Setpoint will
be 40ºF. If the humidity is below the Indoor Humidity Setpoint, then
the Coil Temperature Setpoint will be increased by a maximum of 5ºF.
Units with 2 Digital Compressors
This application requires 2 Suction Pressure Transducers. The lowest
Coil Temperature is used for the Compressor control. Two Stages of
Cooling need to be confi gured for the 2 Compressors. When mechanical
cooling is active, the Compressors will modulate to maintain the Coil
Temperature Setpoint.
The First Stage of Cooling will modulate up. If the First Stage reaches
100% for the Stage Up Delay and the Coil Temperature is above the Coil
Temperature Setpoint, then the Second Stage of Cooling will activate.
The First Stage of Cooling will Lock at 100% and modulate the Second
Stage of Cooling.
If the second compressor reaches 0% for the Stage Down Delay and
the Coil Temperature is below the Coil Temperature Setpoint minus the
Cooling Stage Control Window, then the Second Stage of Cooling will
deactivate. The fi rst Compressor will then modulate to maintain the Coil
Temperature Setpoint.
Units with 4 Digital Compressors (Dual Unit)
The Compressors will Stage Up and Stage Down the same as 2 Digital
Compressors. Number 1 Compressors from both units will modulate
together and number 2 Compressors from both units will modulate
together.
This application requires 2 Suction Pressure Transducers. The lowest
Coil Temperature is used for the Compressor control.
Units with 1 Digital Compressor and
1 ON/OFF Compressor
This application requires 2 Suction Pressure Transducers. The lowest
Coil Temperature is used for the Compressor control. Two Stages of
Cooling need to be confi gured for the 2 Compressors. When mechanical
cooling is active, the Digital Compressor will modulate to maintain the
Coil Temperature Setpoint.
Dehumidifi cation Mode