Carrier WEATHERMASTER 48/50Z030-105 - Manual (Page 67)

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outdoor air dewpoint temperature and will compare this
temperature against the outside air dewpoint temperature
limit configuration (Configuration → ECON → O.DEW). If the
outdoor air dewpoint temperature is greater than O.DEW, free
cooling will not be allowed. Fig. 10 shows a horizontal limit
line in the custom curve of the psychrometric chart. This is the
outdoor air dewpoint limit boundary.
Custom Psychrometric Curves — Refer to the psychrometric
chart and the standard Honeywell A-D curves in Fig. 9. The
curves start from the bottom and rise vertically, angle to the left
and then fold over. This corresponds to the limits imposed by
dry bulb changeover, outdoor enthalpy changeover and
outdoor dewpoint limiting respectively. Therefore, it is now
possible to create any curve desired with the addition of one
outdoor relative humidity sensor and the options for
changeover now available. See Fig. 10 for an example of a
custom curve constructed on a psychrometric chart.
Configuring the Economizer to Communicate Via Actuator
Serial Number — Every actuator used in the Z Series control
system has its own unique serial number. The rooftop control
uses this serial number to communicate with the actuator over
the local equipment network (LEN). These serial numbers are
programmed at the factory and should not need changing.
Should field replacement of an actuator become necessary, it
will be required to configure the serial numbers of the new
actuator. Five individual numbers make up this serial number
and these can be programmed to match the serial number of the
actuator in its Economizer Actuator Configs group, ACT.C
(SN1.1, SN1.2, SN1.3, SN1.4, SN1.5, SN2.1, SN2.2, SN2.3,
SN2.4, SN2.5).
NOTE: The serial numbers for all LEN actuators can be found
inside the control doors of the unit as well as on the actuator
itself. If an actuator is replaced in the field, it is a good idea to
remove the additional peel-off serial number sticker on the
actuator and cover up the old one inside the control doors.
Fig. 10 — Custom Changeover Curve Example
Fig. 9 — Psychrometric Chart for
Enthalpy Control
CONTROL CURVE
CONTROL POINT
(approx Deg) AT 50% RH
A 73
B 68
C 63
D 58