Specifications
Page 42 of 48 IM 934-5
Fault and Protection Codes for Applied PTAC Control Board
Fault code Description Cause for the fault
CE Communication Error 1. Cable not plugged in properly on either LUI or relay board.
2. Defective cable.
Sh Missing Shunt The user congurable shunt for System Select, Control Select Off Fan Cycle, and/or Hydronic Valve is
missing or not placed properly.
E1 Problem with IAS Indoor Air Sensor missing or short.
E2 Problem with ICS Indoor Coil Sensor missing or short.
E3 Problem with OCS Outdoor Coil Sensor missing or short.
E4 Problem with OAS Outdoor Air Sensor missing or short.
E5 Problem with HFLO Sensor HFLO Sensor missing or short on control board or heating medium >250ºF. Check for installation /
connection of HFLO sensor. Should be on coil return line.
Protection
Description Cause for the fault
code
CF Coil Freeze Protection Indoor coil temperature has been below 32ºF for 5 minutes.
Protection feature and the displayed code are dismissed when indoor coil temperature rises above 49ºF.
Rf Room Freeze Protection Indoor air temperature has dropped below 41ºF. Protection feature and the displayed code are
dismissed when indoor room temperature rises at and above 50ºF.
hI High Room Temperature Indoor air temperature is 5 degrees above maximum setpoint limit. Protection feature and the displayed
code are dismissed when indoor coil temperature rises above 50ºF.
Lo Low Room Temperature Indoor air temperature is 5 degrees below minimum setpoint limit.
LA Low Ambient Lockout Outdoor air temperature is below 25ºF.