Wiring An Enthalpy Switch - Carrier RTU Open v3 Installation And Startup Manual

Wiring an enthalpy switch

Outdoor Air - Part #33CSENTHSW
Return air - Part #33CSENTSEN
The 33CSENTHSW is an outdoor air enthalpy switch/receiver. This control determines the suitability of the outdoor
air as a cooling source, based on the heat content of the air. Differential enthalpy control requires installing a
33CSENTSEN enthalpy sensor in the rooftop unit's return air duct.
Wiring specifications
Cable from sensor to controller:
Maximum length:
To wire an enthalpy switch (outdoor air) to the controller
An enthalpy switch is typically mounted in the outdoor air inlet.
Wiring diagram for a field-installed enthalpy switch:
RTU Open v3
Installation and Start-up Guide
If <100 ft (30.5 meters)
If >100 ft (30.5 meters)
500 feet (152 meters)
35
Installing the RTU Open
22 AWG, unshielded
22 AWG, shielded
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