SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE 
SENSOR
Fig. 37 — Supply-Air Sensor Placement
CO2 Control Set Up — If a CO2 sensor is not being used, proceed to the next section. If a CO2 sensor is being used, per- form 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. 38.
Mechanical Cooling Lockout — Determine the
Dry Bulb Changeover Set Up — Determine the dry bulb changeover set point from Table 3. The settings are A, B, C and D. Locate the ECON SP potentiometer and set the dry bulb changeover set point. See Fig. 38. When the OAT is above this set point, the damper is limited to minimum position setting.
Table 3 — Changeover Set Points
SETTINGS | A | B | C | D | |
Dry Bulb (°F) | 73 | 69 | 66 | 63 | |
Single Enthalpy* (Btu/lb) | 27 | 25 | 24 | 22 | |
Differential Temperature* | 2 | 2 | 2 | 2 | |
(°F, Not Adjustable) | |||||
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Differential Enthalpy* | 1 | 1 | 1 | 1 | |
(Btu/lb, Not Adjustable) | |||||
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If a potentiometer fails, its setting will default to the values in Table 4.
Table 4 — Default Potentiometer Settings
POTENTIOMETER | DEFAULT SETTING |
CO2 SP (PPM) | 1,000 |
MECH CLG LOCKOUT | 47° |
ECON SP | D |
MIN POS (%) | 20 |
Ventilation Air (Minimum Position Set up) — If ventilation air is not required, proceed to Step 5. If ventilation 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) potentiometer. Turn the potentiometer full CCW to fully close the out- door air dampers. Turn the potentiometer gradually clockwise (CW) to the desired position. See Fig. 38.
3.Replace the filter access panel. See Fig. 26. Ensure the fil- ter access panel slides along the tracks and 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 air = Mixture Temp – Return Air Temp Outdoor Temp – Return Air Temp
b.Divide total CFM by percentage outdoor air, this gives outdoor air volume in CFM.
5.Turn on base unit power.
NOTE: The EconoMi$er begins operation three min- utes after power up.
Personal Injury Hazard. Avoid possible injury by keep- ing fingers away from damper blades.
6. See Fig. 39 for barometric relief damper characteristics.
Fig. 38 — EconoMi$er Control Adjustment
Potentiometers (Factory Settings)
WG) | 0.5 |
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0.4 |
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(IN. |
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PRESSURE | 0.3 |
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| 0.2 |
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STATIC | 0.1 |
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0 |
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| 200 | 400 | 600 | 800 | 1000 | 1200 | 1400 | 1600 | |||||||||
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| FLOW (CUBIC FEET/MINUTE) |
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| Fig. 39 — Barometric Relief Capacity |
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