Carrier WeatherMaker 48TC*A04, Service And Maintenance Instructions

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Table 27 – EconoMi$er IV Input/Output Logic
INPUTS OUTPUTS
Demand Control
Ventilation (DCV)
Enthalpy*
Y1 Y2
Compressor N Terminal†
Outdoor Return
Stage
1
Stage
2
Occupied Unoccupied
Damper
Below set
(DCV LED Off)
High
(Free Cooling LED
Off)
Low
On On On On
Minimum position Closed On Off On Off
Off Off Off Off
Low
(Free Cooling LED
On)
High
On On On Off
Modulating** (between
min. position and full-
open)
Modulating** (be-
tween closed and
full-open)
On Off Off Off
Off Off Off Off Minimum position Closed
Above set
(DCV LED On)
High
(Free Cooling LED
Off)
Low
On On On On
Modulating†† (between
min. position and DCV
maximum)
Modulating†† (be-
tween closed and
DCV
maximum)
On Off On Off
Off Off Off Off
Low
(Free Cooling LED
On)
High
On On On Off
Modulating*** Modulating††† On Off Off Off
Off Off Off Off
* For single enthalpy control, the module compares outdoor enthalpy to the ABCD setpoint.
† Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied).
** Modulation is based on the supply-air sensor signal.
†† Modulation is based on the DCV signal.
*** Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV)
or fully open (supply-air signal).
††† Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully
open (supply-air signal).
C06053
Fig. 74 -- EconoMi$er IV Functional View
EconoMi$er IV
Table 27 provides a summary of EconoMi$er IV.
Troubleshooting instructions are enclosed.
A functional view of the EconoMi$er is shown in Fig. 74.
Typical settings, sensor ranges, and jumper positions are
also shown. An EconoMi$er IV simulator program is
available from Carrier to help with EconoMi$er IV
training and troubleshooting.
EconoMi$er IV Standard Sensors
Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10
to 20 mA device used to measure the outdoor-air
temperature. The outdoor-air temperature is used to
determine when the EconoMi$er IV can be used for free
cooling. The sensor is factory-installed on the
EconoMi$er IV in the outdoor airstream. (See Fig. 75.)
The operating range of temperature measurement is 40
_
to
100
_
F (4
_
to 38
_
C). See Fig. 77.
48TC