5
GEN ERAL
This accessory economizer package is designed to save
energy costs by using outdoor air for cooling and
ventilation in place of mechanical cooling whenever
possible. The economizer continuously monitors indoor
and outdoor air conditions and compares them to a
user-selected setpoint to determine if free cooling is
available.
AC CES SO RIES
RXRX-AV02 — Dual Enthalpy Up grade Kit
For maximum energy savings, this upgrade kit will allow
the economizer to compare the outdoor air enthalpy to the
return air enthalpy, instead of a user-selected setpoint to
determine if "free cooling" is available.
RXRX-AR02 - Wall-Mounted Car bon Di ox ide Sen sor
For installations requiring Demand Control Ventilation
(DCV) based upon indoor air levels of carbon dioxide
(CO
2
). When the unit supply fan is running, the CO
2
sensor
modulates the outside air damper to maintain a
user-selected CO
2
level inside the occupied space.
Energy savings are achieved by not bringing in excessive
amounts of outdoor air when the indoor air conditions are
suitable. Energy savings can be substantial on buildings
with highly variable occupancy rates.
Wall-Mounted Remote Potentiometer
For installations requiring remote adjustment of damper
m i n i m u m p o s i ti o n b y t h e o c c u p a n t s , a r e m o te
potentiometer, such as the Honeywell S963B1128 can be
used.
RXRX-BFF02C, RXRX-BFF02D, RXRX-BFF02Y —
Power Exhaust Kit
For installations requiring more space static pressure relief
than can be obtained with the standard barometric relief
damper included with the economizer, a power exhaust kit
can be added.
STARTUP
Attach connector from Economizer Controller to Rooftop
Control Panel Connector and install discharge/mixed air
temperature sensor per installation guide.
AD JUST MENTS
5 po ten ti om eters with screw driver ad just ment slots,
start ing from top of con trol ler
1.
EXH Set — Adjustments for (optional) power ex haust
A. The outside air damper position at which the
power exhaust fan(s) will engage. The LED
labeled EXH below the potentiometer adjustment
will indicate when power exhaust is available.
When the power exhaust call is made, the
controller provides a 60 ±30 second delay before
exhaust fan activation to allow the damper to
reach the appropriate position.
B. Range of adjustment is from 0-100% (2-10V); in
most applications the power exhaust is set to
engage at about 70% outside air.
B. Range of adjustment is from 0-100% (2-10V); in
most applications the minimum position is
adjusted to allow 10% to 25% outside air to enter
the system.
C. The Outside Air Damper Minimum Position
potentiometer can be adjusted at any time.
D. Whenever the "G" (supply fan) signal is present,
the damper will open to this minimum position
unless:
a.
It may modulate to a greater position if
overridden by the CO
2
sensor (DCV).
b.
It may not open if overridden by the discharge
air temperature sensor (Freeze Protect
Mode).
3.
DCV Max — Demand Control Ventilation (DCV)
Maximum Setpoint
A. The DCV maximum position potentiometer allows
the installer to limit the amount of outdoor air flow
into the building when the DCV overrides the
mixed air sensor.
B. Setting the DCV maximum position of the damper
prevents the introduction of large amounts of hot
or cold air into the space.
C. Note: If the DCV maximum position is set below
the outside air damper minimum position, the
minimum position overrides the DCV maximum
position (negating the function of the DCV).
4.
DCV Set — Demand Control Ventilation (DCV)
Setpoint
A. The DCV can be any sensor that provides a
2-10Vdc output. The DCV modulates the outdoor
d a m p e r t o p r o v i d e ve n t i l a t io n b a s e d o n
occupancy. Typically, a carbon dioxide (CO
2
)
sensor is used to indirectly monitor occupancy
level.
B. No cooling signal (e.g.Y1, Y2) is required for the
DCV to override the outdoor air damper when
ventilation requires outdoor air.
C. The controller must receive a "G" (supply fan)
signal to open the damper.
D. Range of adjustment is from 2 Volts to 10 Volts.
E. The DCV setpoint can be adjusted at any time.
DI RECT MOUNT ECONOMIZER SE QUENCE OF OP ER A TION
FIGURE 6