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Fig. 27 — Enthalpy Switch/Receiver Dimension
(33CSENTHSW)
Fig. 28 — Enthalpy Sensor Dimensions
OUTDOOR ENTHALPY CONTROL REQUIRES ONLY AN
ENTHALPY SWITCH/RECEIVER (33CSENTHSW).
The enthalpy switch/receiver is mounted in the outdoor air inlet
and calculates outdoor air enthalpy. The enthalpy switch/receiver
energizes the relay output when the outdoor enthalpy is above 28
Btu/lb OR dry bulb temperature is above 75°F and is de-energized
when the outdoor enthalpy is below 27 Btu/lb AND dry bulb tem
-
perature is below 74.5°F. The relay output is wired to the unit
economizer which will open or close depending on the output of
the switch.
NOTE: The enthalpy calculation is done using an average altitude
of 1000 ft above sea level.
Mount the enthalpy switch/receiver in a location where the
outdoor air can be sampled (such as the outdoor air intake). The
enthalpy switch/receiver is not a NEMA 4 (National Electrical
Manufacturers Association) enclosure and should be mounted in a
location that is not exposed to outdoor elements such as rain or
snow. Use two field-supplied no. 8 x 3/4 in. TEK screws. Insert
the screws through the holes in the sides of the enthalpy switch/
receiver.
Carrier recommends the use of 18 or 22 AWG (American Wire
Gage) twisted pair or shielded cable for all wiring. All connections
must be made with 1/4 in. female spade connectors.
A 24 vac transformer is required to power the enthalpy
switch/receiver. The PremierLink™
board provides 24 vac, as
shown in Fig. 29. Connect the GND and 24 vac terminals on the
enthalpy switch/receiver to the terminals on the transformer. On
some applications, the power from the economizer harness can be
used to power the enthalpy switch/receiver. To power the enthalpy
switch/receiver from the economizer harness, connect power of
the enthalpy switch/receiver to the red and brown wires (1 and 4)
on the economizer harness.
For connection to rooftop units with PremierLink control, connect
the LOW enthalpy terminal on the enthalpy switch/receiver to
J4-pin 2 of the PremierLink control on the HVAC unit. The switch
can be powered through the PremierLink control board if desired.
Wire the 24 vac terminal on the enthalpy switch/receiver to J4-pin
1 on the PremierLink control. Wire the GND terminal on the
enthalpy switch/receiver to J1- pin 2 on the PremierLink control.
The HI enthalpy terminal is not used. (See Fig. 29.)
DIFFERENTIAL ENTHALPY CONTROL REQUIRES
BOTH
AN
ENTHALPY
SWITCH/RECEIVER
(33CSENTHSW) AND AN ENTHALPY SENSOR
(33CSENTSEN).
The enthalpy switch/receiver is mounted in the outdoor air inlet
and calculates outdoor air enthalpy. The enthalpy sensor is
mounted in the return airstream and calculates the enthalpy of the
indoor air.
For differential enthalpy control, the enthalpy switch/receiver
energizes the HI enthalpy relay output when the outdoor enthalpy
is greater than the indoor enthalpy. The LOW enthalpy terminal is
energized when the outdoor enthalpy is lower than the indoor
enthalpy. The relay output is wired to the unit economizer which
will open or close depending on the output of the switch.
NOTE: The enthalpy calculation is done using an average altitude
of 1000 ft above sea level.
Mount the enthalpy sensor in a location where the indoor air can
be sampled (such as the return air duct). The enthalpy sensor is not
a NEMA 4 enclosure and should be mounted in a location that is
not exposed to outdoor elements such as rain or snow. Use two
field-supplied no. 8 x 3/4 in. female spade connectors.
The PremierLink
board provides 24 vac to power the enthalpy
switch/receiver. Connect the GND and 24 vac terminals on the
enthalpy switch/receiver to the terminals on the transformer. On
some applications, the power from the economizer harness can be
used to power the enthalpy switch/receiver. To power the enthalpy
switch/receiver from the economizer harness, connect power of
the enthalpy switch the red and brown wires (1 and 4) on the
economizer harness. Connect the LOW enthalpy terminal on the
enthalpy switch/receiver to J4-pin 2 of the PremierLink control on
the HVAC unit. The switch can be powered through the Premier
-
Link control board, if desired. Wire the 24 vac terminal on the
enthalpy switch/receiver to J4-pin 1 on the PremierLink control.
Wire the GND terminal on the enthalpy switch/receiver to J1-pin 2
on the PremierLink control. The HI enthalpy terminal is not used.
(See Fig. 29.)
Connect the 4-20 mA IN terminal on the enthalpy switch/receiver
to the 4-20 mA OUT terminal on the return air enthalpy sensor.
33CSENTHSW
Thermistor
Humidity Sensor
®
mA in VDC out
4-20
24-36
4.253”
(108.03 mm)
3.352”
(85.14 mm)
1.676”
(42.57 mm)
.25”
(6.35 mm)
3.75”
(95.25 mm)
1.375”
(34.925 mm)
Model #: HH57ZC003
Power: 24 VAC
Output: 10 A Form 1C Relay w/
24 VAC Sourced Power
RETURN AIR
ENTH. SENSOR
HI
LOW GND
24
VAC
ENTHALPY
33CSENTSEN
Thermistor
Humidity Sensor
®
mA OUT
VDC IN
4-20
24-36
4.253”
(108.03 mm)
3.352”
(85.14 mm)
1.676”
(42.57 mm)
.25”
(6.35 mm)
3.75”
(95.25 mm)
1.375”
(34.925 mm)
Model #: HH57ZC001
Power: 24 to 36 VDC
Span: 0 to 50 BTU/lb
Output: 4 to 20mA