Repair Section
51
Alarm clear method
• Self-diagnostic codes are not displayed for the MWT. To identify the cause, check the LED on
the relay board and refer to the charts on page 48 to 50.
Self-Diagnostic
Code
Possible Cause
Alarm Clear Method
User
Mode
Service
Mode
Wall Mounted Controller (WMC) Millivolt Wall Thermostat (MWT)
AL AL Fire alarm input
Press RESET button, then
press ON/OFF button.
Reset the power from the circuit
breaker.
PU PU
Condensation overflow (Internal
drain pump)
E07 E07
Condensation overflow
(Optional condensate pump)
HP HP
High-pressure signal detected Alarm clears automatically. Alarm clears automatically.
High-pressure protection
activated
Press RESET button, then
press ON/OFF button.
Reset the power from the circuit
breaker.
E01 E01
WMC room thermistor (RTS1)
failure
E02 E02
Evaporator inlet air thermistor
(RTS2) failure
E03 E03
Entering water thermistor
(EWTS) failure
E04 E04
Condenser thermistor (CTS1)
failure
E05 E05
Evaporator pipe inlet thermistor
(CTS2) failure
E06 E06
Evaporator pipe outlet
thermistor (CTS3) failure
E08 E08 WMC communication error
E09 E09 Evaporator fan motor locked
OL OL Compressor overload
E11 E11
STI module communication error
E12
E14 Compressor input over current
Press RESET button, turn off
the circuit breaker, then turn on
the circuit breaker and press
ON/OFF button.
E15 Compressor lock failure
E16
Compressor phase interruption
abnormality
E17
Motor position detection
abnormality