Carrier 50HJQ016 Installation, Start-Up And Service Instructions Manual page 12

COMMISSIONING — The EconoMi$er saves energy when
it uses outdoor air to provide free cooling instead of mechani-
cal air conditioning. The EconoMi$er switchover strategy de-
termines if the outdoor air is suitable for free cooling. The
EconoMi$er chooses the switchover strategy with the most en-
ergy savings, provided that the required sensors are connected
and functioning normally.
IMPORTANT: If a sensor stops functioning nor-
mally (becomes unreliable), the EconoMi$er
switches to the next best strategy.
Refer to Table 4 to determine the sensors required for each
strategy.
Differential Enthalpy Switchover Strategy — The differen-
tial 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 indicate
the change of configuration.
SENSOR
COVER
Fig. 22 — Outdoor-Air Sensor Location
MOUNTING SCREW
Fig. 23 — Outdoor-Air Sensor Details
OUTSIDE AIR SENSOR
SENSOR
WIRING
CONNECTIONS
MOUNTING
SCREW
WIRING
HARNESS
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$er Control Module.
CO CONTROL SETUP — If a CO
2
used, proceed to the next section. If a CO
perform the following:
1. Determine the value at which you want the minimum
position of the dampers to begin opening to allow a
greater amount of outdoor air to enter. The range is
800 to 1,400 ppm.
2. Locate the CO SP (PPM) potentiometer and adjust to the
2
desired set point. See Fig. 17.
MECHANICAL COOLING LOCKOUT — Determine the
outdoor-air temperature at which you want the mechanical
cooling (compressors) to be disabled. Locate the mechanical
cooling lockout (MECH CLG LOCKOUT) potentiometer. To
disable this feature, turn the potentiometer counterclockwise
(CCW) to the OFF position. Otherwise, set the value between
10 and 60 F. Mechanical cooling will not operate when the out-
door air temperature is below this value. See Fig. 17.
DRY BULB CHANGEOVER SET UP — Determine the dry
bulb changeover set point from Table 5. The settings are A, B,
C and D. Locate the ECON SP potentiometer and set the dry
bulb changeover set point. See Fig. 17. When the OAT is above
this set point, the damper is limited to minimum position
setting.
If a potentiometer fails, its setting will default to the values
in Table 6.
VENTILATION AIR (Minimum Position Set Up) — If ven-
tilation air is not required, skip this section. If ventilation air is
required, perform the following:
1. The indoor fan must be on to set the ventilation air.
Either put the thermostat in the continuous fan mode or
jumper the R and G terminals at the rooftop unit con-
nection board.
2. Locate the minimum position (MIN POS) potentiometer.
Turn the potentiometer full CCW to fully close the out-
door air dampers. Turn the potentiometer gradually
clockwise (CW) to the desired position. See Fig. 17.
3. Replace the filter access panel. See Fig. 19. Ensure the fil-
ter access panel is securely engaged.
4. Calculate the minimum airflow across the EconoMi$er.
a. Calculate % of outside air using the following
formula.
% Outdoor air through EconoMi$er
% Outdoor air =
b. Multiply total CFM by percentage outdoor air, this
gives outdoor air volume in CFM.
Personal Injury Hazard. Avoid possible injury by keep-
ing fingers away from damper blades.
12
sensor is not being
2
sensor is being used,
2
Mixture Temp – Return Air Temp
Outdoor Temp – Return Air Temp