Bryant Durapac Plus Series 551a User Manual

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C. Commissioning

The EconoMi$er saves energy when it uses outdoor air to
provide free cooling instead of mechanical air conditioning.
The EconoMi$er switchover strategy determines if the out-
door air is suitable for free cooling. The EconoMi$er chooses
the switchover strategy with the most energy savings, pro-
vided that the required sensors are connected and function-
ing normally.

IMPORTANT: If a sensor stops functioning normally
(becomes unreliable), the EconoMi$er switches to the next
best strategy.

Refer to Table 5 to determine the sensors required for each
strategy.

Differential Enthalpy Switchover Strategy

The differential enthalpy switchover strategy must be
selected manually, if required. To enable, press and hold the
CONFIG button for 30 seconds, then release. The LED will
flash twice to indicate the change of configuration.

To return to single enthalpy mode, press and hold the CON-
FIG button for 30 seconds. The LED will flash once to indi-
cate the change of configuration.

D. Discharge Air Thermistor (DAT)

The discharge air thermistor is factory-mounted on the
supply-fan housing in the fan section of the unit. The DAT is
factory-wired to the EconoMi$er Control Module.

E. CO

Control Setup

If a CO

sensor is not being used, proceed to the next section.

If a CO

sensor is being used, perform the following:

1. Determine the value at which you want the minimum

position of the dampers to begin opening to allow a
greater amount of outdoor air to enter. The range is
800 to 1,400 ppm.

2. Locate the CO

SP (PPM) potentiometer and adjust

to the desired set point. See Fig. 16.

Fig. 19 — Seal Strip Location

(Air Hood Cross-Sectional View)

NOTE: The outdoor-air hood comes with a baffle which is used on
180 and 240 units only; discard baffle for 155 units.

Fig. 20 — Outdoor-Air Hood Details

HOOD TOP
PANEL

HOOD SIDE
PANELS (2)

BAFFLE
(180 AND
240 ONLY)

LOWER
FILTER
RETAINER

FILTER SUPPORT
BRACKET

HOOD DRAIN PAN

UPPER FILTER RETAINER

BAFFLE (180 AND 240 ONLY)

LOWER FILTER
RETAINER

FILTER SUPPORT
BRACKET

SENSOR
COVER

OUTSIDE AIR SENSOR

MOUNTING
SCREW

MOUNTING SCREW

WIRING
HARNESS

SENSOR
WIRING
CONNECTIONS

Fig. 22 — Outdoor-Air Sensor Details

Fig. 21 — Outdoor-Air Sensor Location