Carrier WeatherMaster Puron 48HC D17, Service And Maintenance Instructions, Page: 50 / 100

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Fig. 62 — Supply Air Sensor Location
Fig. 63 — Outside Air Temperature Changeover
Setpoints
OUTDOOR AIR LOCKOUT SENSOR
The EconoMi$er IV is equipped with an ambient temperature
lockout switch located in the outdoor airstream which is used
to lock out the compressors below a 42°F (6°C) ambient tem-
perature. (See Fig. 54.)
ECONOMI$ER IV CONTROL MODES
Determine the EconoMi$er IV control mode before set up of
the control. Some modes of operation may require different
sensors. (See Table 21.) The EconoMi$er IV is supplied from
the factory with a supply-air temperature sensor and an out-
door-air temperature sensor. This allows for operation of the
EconoMi$er IV with outdoor air dry bulb changeover control.
Additional accessories can be added to allow for different
types of changeover control and operation of the EconoMi$er
IV and unit.
OUTDOOR DRY BULB CHANGEOVER
The standard controller is shipped from the factory configured
for outdoor dry bulb changeover control. The outdoor air and
supply air temperature sensors are included as standard. For
this control mode, the outdoor temperature is compared to an
adjustable setpoint selected on the control. If the outdoor-air
temperature is above the setpoint, the EconoMi$er IV will ad-
just the outside air dampers to minimum position. If the out-
door-air temperature is below the setpoint, the position of the
outside air dampers will be controlled to provided free cooling
using outdoor air. When in this mode, the LED next to the free
cooling setpoint potentiometer will be on. The changeover
temperature setpoint is controlled by the free cooling setpoint
potentiometer located on the control. (See Fig. 64.) The scale
on the potentiometer is A, B, C, and D. See Fig. 65 for the cor-
responding temperature changeover values.
Fig. 64 — EconoMi$er IV Controller Potentiometer
and LED Locations
Fig. 65 — Outdoor-Air Damper Leakage
DIFFERENTIAL DRY BULB CONTROL
For differential dry bulb control, the standard outdoor dry bulb
sensor is used in conjunction with an additional accessory dry
bulb sensor (part number CRTEMPSN002A00). The accessory
sensor must be mounted in the return airstream. (See Fig. 66.)
Wiring is provided in the EconoMi$er IV wiring harness.
In this mode of operation, the outdoor-air temperature is com-
pared to the return-air temperature and the lower temperature
airstream is used for cooling. When using this mode of change-
over control, turn the enthalpy setpoint potentiometer fully
clockwise to the D setting. (See Fig. 64.)
IMPORTANT: The optional EconoMi$er2 does not include
a controller. The EconoMi$er2 is operated by a 4 to 20 mA
signal from an existing field-supplied controller. See
Fig. 56 for wiring information.
SUPPLY
AIR TEMPERATURE
SENSOR MOUNTING
LOCATION
SUPPLY AIR
TEMPERATURE
SENSOR
(SEALED
INSIDE CRIMP
END)
LED ON
LED ON
LED ON
LED ON
LED OFF
19
1 8
LED OFF
LED OFF
LED OFF
17
16
15
14
1 3
12
11
10
9
40 45
50
55 60 65
70
75 8 0 8 5 90 95
100
DEGREE S FAHRENHEIT
mA
D
C
B
A
0
5
10
15
20
25
3 0
0.1 3 0.20 0.22 0.25 0. 3 0 0. 3 5 0.40 0.45 0.50
S TATIC PRE SS URE (in. wg)
FLOW
IN
CUBIC
FEET
PER
MINUTE
(cfm)