Carrier 48HJD005-007 User Manual

Page 18

Control Setup — If a CO

sensor is not being used, pro-

ceed to the next section. If a CO

sensor is being used, perform

the following:

1. Determine the value at which you want the minimum po-

sition 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. 35.

Mechanical Cooling Lockout — Determine the outdoor-air
temperature at which you want the mechanical cooling (com-
pressors) to be disabled. Locate the mechanical cooling lockout
(MECH CLG LOCKOUT) potentiometer. To disable this fea-
ture, turn the potentiometer counterclockwise (CCW) to the
OFF position. Otherwise, set the value between 10 and 60 F.
Mechanical cooling will not operate when the outdoor air
temperature is below this value. See Fig. 35.
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. 35. When the OAT is above this
set point, the damper is limited to minimum position setting.

Table 3 — Changeover Set Points

*Field-installed accessory.

If a potentiometer fails, its setting will default to the values

in Table 4.

Table 4 — Default Potentiometer Settings

Ventilation Air (Minimum Position Set Up) — If ventilation
air is not required, proceed to Step 5. If ventilation air is re-
quired, 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. 35.

3. Replace the filter access panel. See Fig. 24. Ensure the fil-

ter access panel slides along the tracks and is securely
engaged.

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

Calculate % of outside air using the following
formula.
% Outdoor air through EconoMi$er

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 minutes after
power up.

6. See Fig. 36 for barometric relief damper characteristics.

SETTINGS

Dry Bulb (°F)

Single Enthalpy* (Btu/lb)

Differential Temperature* (°F, Not Adjustable)

Differential Enthalpy* (Btu/lb, Not Adjustable)

POTENTIOMETER

DEFAULT SETTING

SP (PPM)

1,000

MECH CLG LOCKOUT

47°

ECON SP

MIN POS (%)

% Outdoor air =

Mixture Temp –
Return Air Temp
Outdoor Temp –
Return Air Temp

Personal Injury Hazard. Avoid possible injury by keep-
ing fingers away from damper blades.

SUPPLY AIR
TEMPERATURE
SENSOR
MOUNTING
LOCATION

SUPPLY AIR
TEMPERATURE
SENSOR

Fig. 34 — Supply-Air Sensor Placement

400

800

1200

1600

2000

2400

FLOW (CUBIC FEET/MINUTE)

0.5

0.4

0.3

0.2

0.1

TIC PRESSURE (IN.WG)

Fig. 35 — EconoMi$er Control Adjustment

Potentiometers (Factory Settings)

Fig. 36 — Barometric Relief Capacity