43
TROUBLESHOOTING
Ifthe display module doesn’t power up afterpower is applied, check the Rc/Rh
andC terminalsfor 24VAC.If 24VAC is present,check the voltage betweenVg
and V+. This voltagewill be approximately 12--20VDC.If voltage is present,
check the polarity to make sure it is wired correctly. The display will not power
up if polarity is reversed.

Error Codes

“-- -- ” --If AC/HP Control cannot properly readroom temperature, display will
indicate“----”and all outputs (exceptfan, if on) will turn off. In the case where
the installer has selected to average the local sensor and the remote roo m sensor,
the AC/HP display will alternate between “----” for the failed sensor and the
temperaturesensed by the working sensor every 10 seconds.The control will
operatefrom the temperaturesensed by the working sensor.
E1 -- If the Display Module and the Equipment Control Module cannot
communicatevia two--wireconnection,an E1 will be displayed.
E2 --ThereisnoE2errormessage.
E3 --If AC/HP Control cannot properly read outdoor temperature, and itis
needed for proper operation, display will indicate “----” in the outdoor
temperature location.
E4 --If AC/HP Control’s internalmemory fails, E4 will be displayed.Replace
AC/HP Control.
Table3 can be usedas a troubleshooting toolfor determining whichoutputs will
be active for ap articular configuration and each operating mode.