Carrier 48TJ016-028 - Manual (Page 21)

DIFFERENTIAL ENTHALPY CONTROL (Fig. 29) —
Differentiiil enthalpy control requires both an enthiilpy switch/
receiver
(.33CSENTHSW) and an enthtJpy 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 ciilcu-
lates the enth;ilpy of the indoor air.
Tire enthalpy switclr/receiver energizes the HI Enthalpy re­
lay output when the outdoor enthalpy is greater tlran tire indoor
enthalpy. Tire LOW Entlralpy terminal is energized when the
outdoor entlralpy is lower than the indoor enthalpy. Tire relay
output is wired to the unit economizer which will open or close
depending on the output of the switch.
NOTE; Tire enthalpy calculation is done using an average alti­
tude of 1000 ft above sea level.
Mounting — Mount the enthalpy switch/receiver in a location
where tire outdoor air can be sampled (such as the outdoor air
intitke). Tire enthalpy switch/receiver is not a NEMA 4 enclo­
sure and should be mounted in a location that is not exposed to
outdoor elements such as rain, snow, or direct sunlight. Use
two field-supplied no. 8 x Yr-in. ТЕК screws. Insert the screws
through the holes in the sides of the enthalpy switclr/receiver.
Mount the enthalpy sensor in a location where the indoor air
can be siunpled (such as the return air duct). Tire 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 V
4 -in. ТЕК screws. Insert
the screws tlrrough the holes in tire sides of the enthalpy sensor.
Wiring — Carrier recommends the use of 18 to 22 AWG
twisted pair or shielded cable for all wiring. All connections
must be made with Vr-in. female spade connectors.
The PremierLink'f’'* board provides 24-vac to power the
enthalpy switch/receiver. Connect the GND and 24 VAC termi­
nals on the enthalpy switclr/receiver to the terminals on
tire transformer. On some applications, tire power from the
economizer htu'ness 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 econo­
mizer 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 tlie 24VAC terminal on the
enthidpy switcli/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. 28.
Connect the 4-20 mA IN terminal on the enthalpy switch/
receiver to the 4-20 mA OUT terminal on the return air en-
tlialpy sensor. Connect the 24-36 VDC OUT terminiil on the
enthalpy switcli/receiver to the 24-36 VDC IN terminal on the
return air enthalpy sensor. See Fig. 29.
Enthalpy Switch/Receiver Jumper Settings — There are two
jumpers. One jumper determines the mode of the entlialpy
switch/receiver. The other jumper is not used. To access the
jumpers, remove the 4 screws holding the cover on the
enthalpy switcli/receiver and then remove the cover. Tlie fac-
toiy settings for the jumpers £U'e M1 and OFF.
The mode jumper should be set to M2 for differential en-
tlialpy control. The factoiy test jumper should remain on OFF
or the enthalpy switch/receiver will not calculate enthalpy.
120 VAC
LINE VOLTAGE
LEGEND
N/C — Normally Closed
N/O — Normally Open
JUMPER SETTINGS FOR 33CSENTHSW
1 °
о 1 1 о
I o o o
o o o
JUMPER SETTINGS FOR 33CSENTSEN
0 О cn
^ о О о 1
-S? r-P
Fig. 29 — Differential Enthalpy Control Wiring
■ o o ■ o o o
B o o 1 o o o
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