Manufacturer reserves the right to change specifications or designs without notice.
10.2019
ESI (Ultra) Service Manual
44/68
1.
Error definition:
P8: The detected compressor voltage by main chip is less than 310VDC.
E8: System locks up when P8 has occurred three times in 60 minutes.
2.
Possible causes:
Abnormal power supply voltage
Damaged main control board
1.
Error definition:
The detected compressor line sequence is incorrect for it’s difficult to build pressure difference.
2.
Possible causes:
Damaged pressure sensor
Incorrect U/V/W connections between main control board and compressor terminals
Damaged EEV or indoor TXV
Damaged main control board
Display
or
Low compressor voltage protection
Abnormal power supply voltage (e.g. less than175VAC).
YES
Check if there are any other high power consumption facilities
sharing the same power supply?
NO
Replace the main control board
Contact power supply agency to
verify that they are sending the
correct voltage.
Display
Incorrect compressor line sequence
Use ESS Pro App or BS3 button to check high pressure and low
pressure values. Are they approximately equal in stop condition.
NO
YES
Are the compressor wirings (U/V/W) connected properly based
NO
on the wiring diagram?
YES
Cooling:
Has the
non-bleed TXV
been used for indoor unit?
NO
Heating:
No liquid slugging protection in the last week?
YES
Turn off the power supply for five minutes then turn on again to
NO
restart the system. Does the fault remain?
YES
Replace the main control board
Back to normal
Cooling:
Use non-bleed TXV
Heating:
Refer to P7/E7 code to
troubleshoot the EEV opening
Correct U/V/W wirings
Refer to F7/F8 code to trouble-
shoot the pressure sensor