Bryant 581A Seal Strip Location, Outdoor-AirHood Details, A.Enthalpy Control Installation

3.Secure lower filter retainer and long section of filter support bracket to unit. See Fig. 22. Leave screws loose on 180 and 240 units.

4.Slide baffle (sizes 180 and 240) behind lower filter retainer and tighten screws.

5.Loosen sheet metal screws for top panel of base unit- located above outdoor-air inlet opening, and remove screws for hood side panels located on the sides of the outdoor-air inlet opening.

6.Match notches in hood top panel with unit top panel screws. Insert hood flange between top panel flange and unit. Tighten screws.

7.Hold hood side panel flanges flat against unit, and install screws removed in Step 5.

Fig. 21 — Seal Strip Location

BAFFLE (180 AND 240 SIZES 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 sizes 180 and 240 only. Discard baffle for size 155 units.

Fig. 22 — Outdoor-Air Hood Details

8.Insert outdoor-air inlet screens and spacer in channel created by lower filter retainer and filter support bracket.

9.Attach remaining short section of filter support bracket.

A.Enthalpy Control Installation

NOTE: The accessory outdoor-air enthalpy sensor must be installed BEFORE the economizer hoods are installed on the unit or hoods will have to be removed.

1.Remove and discard the factory-installed jumper assembly containing the 800-ohm resistor on the

economizer control module (between terminals SR and +). See Fig. 18.

2.Remove black wire assembly containing the 620-ohm resistor from between economizer control module ter-

minal SO and the outdoor-air thermostat (OAT). Place this wire assembly (containing the 620-ohm resistor)

between economizer control module terminals SR and +, replacing the jumper removed in Step 1. See Fig. 18.

3.Disconnect the blue wire from the OAT.

4.Remove OAT from the outside of the economizer. See Fig. 17.

5.Mount the enthalpy sensor (Fig. 23) to the econo- mizer on the outside of the unit (in the same location from which the OAT was removed) using the 2 screws provided. See Fig. 17.

6.Reconnect the blue wire removed in Step 3 to the enthalpy sensor terminal +.

7.Cut the violet wire provided to desired length and terminate with quick-connect terminal provided. Route the violet wire from the enthalpy sensor termi- nal S, through the snap bushing, and to the econo- mizer control module terminal SO. See Fig. 18.

8.Set changeover set point to the desired location. See Fig. 24.

NOTE: For maximum benefit of outdoor air, set the enthalpy control to the “A” setting. At this setting, when the relative humidity is 50% and the outdoor air is below 74 F, the relay contacts on the sensor will be closed.

9. Reinstall economizer hoods if removed.

IMPORTANT: Be sure all seal strips and RTV sealant are intact. A watertight seal to inside of unit must be maintained.

Fig. 23 — Outdoor-Air and Return-Air

Enthalpy Sensor

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