15, H. Ventilation Air Minimum Position Set Up

H. Ventilation Air (Minimum Position Set Up)

If ventilation air is not required, skip this section. If ventila- tion air is required, perform the following:

1.The indoor fan must be on to set the ventilation air. Either put the thermostat in the continuous fan mode or jumper the R and G terminals at the rooftop unit connection board.

2.Locate the minimum position (MIN POS) potentiome- ter. Turn the potentiometer full CCW to fully close the outdoor air dampers. Turn the potentiometer gradually clockwise (CW) to the desired position. See Fig. 16.

3.Replace the filter access panel. See Fig. 18. Ensure the filter access panel is securely engaged.

4.Calculate the minimum airflow across the EconoMi$er.

a.Calculate % of outside air using the following formula.

% Outdoor air through EconoMi$er

% Outdoor	=	Mixture Temp – Return Air Temp
air		Outdoor Temp – Return Air Temp

b.Multiply total CFM by percentage outdoor air, this gives outdoor air volume in CFM.

WARNING: Personal Injury Hazard. Avoid possible injury by keeping fingers away from damper blades.

IX. STEP 9 — INSTALL ALL ACCESSORIES

After all the factory-installed options have been adjusted, install all field-installed accessories. Refer to the accessory installation instructions included with each accessory.

A. Motormaster® I Control Installation (551A155 and 180 Only)

Install Field-Fabricated Wind Baffles

Wind baffles must be field-fabricated for all units to ensure proper cooling cycle operation at low ambient temperatures. See Fig. 25 for baffle details. Use 20-gage, galvanized sheet metal, or similar corrosion-resistant metal for baffles. Use field-supplied screws to attach baffles to unit. Screws should be 1/4-in. diameter and 5/8-in. long. Drill required screw holes for mounting baffles.

CAUTION: To avoid damage to the refrigerant coils and electrical components, use recommended screw sizes only. Use care when drilling holes.