5742640-TIM-A-0419
Johnson Controls Ducted Systems
35
• Lit whenever 24 volts AC power is present to the RRS
Economizer Controller C and R pins
• FAULT (red)
• Lit, then flashes during the boot-up sequence of the RRS
Economizer Controller
• Not lit when there are no Alarms active
• Double-flash/pause continuously when Alarms are active
• SA BUS (green)
• Will not be lit
Menu Structure
The top level menus are:
• STATUS
• ALARMS
• SUMMARY
ECONOMIZER, POWER EXHAUST,
COMPRESSOR
• COMMISSION
• CONTROLLER SETTINGS
• UPDATE
• DETAILS
• SELF TEST
• VIEW RESULTS
NOTE:
Your menu parameters will be different depending on
your configuration. Refer to the RRS Economizer
Control Quick Start Guide P/N 5292230-USG available
from your equipment dealer or distributor.
RRS Economizer Controller Parameter Menu Functions
There are several "conditional" parameters within the menu.
Parameters for temperature, humidity and CO
2
inputs are only
shown in the menu once sensor presence has been detected.
Parameters associated with a function are only shown in the
menu when that function is enabled.
Smart Equipment™ Economizer Sequences
Units with the Smart Equipment™ Control will have a factory
option or field kit with Johnson Controls Economizer.
Several functions can drive the economizer, including: minimum
position, free cooling, economizer loading, and minimum
outdoor air supply.
Economizer Minimum Position
The economizer minimum position is set during occupied mode
when outside air is not suitable for free cooling. The position of
the damper is set proportionally between the "Economizer
Minimum Position and the Economizer Minimum Position Low
Speed Fan" set points, in relationship to the VFD output
percentage. On a constant volume single speed supply fan
system both set-points should be set to the same value.
Free Cooling
Four types of free cooling options are available: dry bulb
changeover, single enthalpy, dual enthalpy changeover, and
Auto.
Dry Bulb Changeover
For dry bulb economizer operation, the outside air is suitable for
free cooling if the outside air temperature is 1°F below the
Economizer OAT Enable Setpoint
and
1°F below the Return Air
Temperature.
Free cooling is no longer available if the outside air temperature
rises above
either
the Economizer OAT Enable setpoint
or
the
return air temperature.
Single Enthalpy Changeover
For single enthalpy economizer operation, the outside air is
suitable for free cooling if the outside air enthalpy is at least 1
BTU/lb below the Economizer Outside Air Enthalpy Setpoint
and
the outside air temperature is no greater than the RAT plus
9°F.
If the outside air temperature rises above the RAT plus 10°F,
free cooling is no longer available. The outside air temperature
must drop to no greater than RAT plus 9°F to enter free cooling
again.
Free cooling is no longer available if the outside air enthalpy
rises above the Economizer Outside Air Enthalpy Setpoint.
Dual Enthalpy Changeover
For dual enthalpy economizer operation, the outside air
enthalpy must be lower than the return air enthalpy by 1 btu/lb
AND the outside air temperature is no greater than the RAT
plus 9°F.
Auto
The control determines the type of free cooling changeover
based on which sensors are present and reliable. Conditions
include:
• Return and outside air dry bulb = dry bulb changeover
• Return and outside air dry bulb and outside air humidity =
single enthalpy
• Return and outside air dry bulb and return and outside air
humidity = dual enthalpy
• If either the return or outside air dry bulb sensors are
unreliable, free cooling is not available
Free Cooling Operation
When the control determines that the outside air is suitable, the
first stage of cooling will always be free cooling.
