Installing the RTU Open
   
 
 
 
RTU Open v3    CARRIER CORPORATION ©2019  
Installation and Start-up Guide    All rights reserved 
  37 
 
 
To wire an enthalpy switch (differential) to the controller 
 
Wiring diagram for optional enthalpy sensor mounted in the return air for differential enthalpy:
 
 
 
 
 
 
Filter - Part #CRSTATUS005A00 or field-supplied 
Fan status - Part #CRSTATUS005A00 or field-supplied 
 
Filter and/or fan status switches may be installed to provide a 
 indication or 
 status.  
 
 
 
Wiring specifications 
 
Cable from sensor to controller:  If <100 ft (30.5 meters)       22 AWG, unshielded 
If >100 ft (30.5 meters)        22 AWG, shielded 
Maximum length:  500 feet (152 meters)