Discharge Air Thermistor DAT, CO2 Control Setup

SENSOR	OUTSIDE AIR SENSOR
COVER

Fig. 19 — Seal Strip Location

(Air Hood Cross-Sectional View)

BAFFLE (180 AND 240 ONLY)

LOWER FILTER

RETAINER

FILTER SUPPORT

BRACKET

HOOD SIDE

PANELS (2)

HOOD TOP PANEL

BAFFLE

(180 AND

240 ONLY)

LOWER

FILTER

RETAINER

FILTER SUPPORT

BRACKET

HOOD DRAIN PAN

UPPER FILTER RETAINER

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

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.

Fig. 21 — Outdoor-Air Sensor Location

MOUNTING SCREW

SENSOR

WIRING

CONNECTIONS

MOUNTING

SCREW

WIRING

HARNESS

Fig. 22 — Outdoor-Air Sensor Details

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. CO2 Control Setup

If a CO2 sensor is not being used, proceed to the next section. If a CO2 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 CO2 SP (PPM) potentiometer and adjust to the desired set point. See Fig. 16.

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