Manufacturer reserves the right to change specifications or designs without notice.
10.2019
ESI (Ultra) Service Manual
38/68
1.
Error definition:
P3: The detected discharge temperature(TD) is no less than specified value.
Cooling: 248
°
F Heating: 230
°
F
E3: System locks up when P3 has occurred six times within 3 hours.
2.
Possible causes:
Too little refrigerant remains in the system
Dirty plugging of EEV or indoor TXV
Damaged discharge temperature sensor
Damaged main control board
TIPS:
Technically measure the DC voltage of the temperature sensor also works when outdoor unit powers on.
NOTE: Normal resistance for compressor
3-phase resistance (UV, UW, VW) for compressor is less than 5Ω.
The insulation resistance (any phase to Ground) for compressor is greater than 100KΩ.
Display
or
Compressor discharge temperature
(TD) protection
NO
YES
Check whether the compressor discharge temperature sensor is
properly seated on the discharge pipe and securely connected to
CN7 terminal on the main control board.
NO
YES
Turn off the power supply to unplug the TD sensor, check if the
NO
resistance is in the range of
Temperature sensor B
. *
TIPS
YES
Use AUTO charge mode in cooling or monitor DSH in heating to
check if too little refrigerant remains in the system.
YES
NO
YES
NO
Is there abnormal sound or vibration for compressor? Double
check if the compressor is open-circuited. *
NOTE
YES
NO
Replace the main control board
Recover refrigerant from the
system to replace the compressor
Whether the low pressure has been evacuated?
Cooling mode:
Check if the
indoor TXV is dirty plugging.
Heating mode:
Check if the
outdoor EEV is dirty plugging.
Add R410A refrigerant
Replace the faulty sensor
Reset the sensor or reconnect the
wire
Open the service valve
Are the service valves of outdoor unit open?