Daikin GYEQ20AN Service Manual page 174

Flow Charts for Troubleshooting
38
BS Unit Circuit Switch Failure
Sub-code 0: With PH higher than 2.0 MPa and PH-PL higher than 1.2 MPa, condition (1) or (2) below
Description (1) With the indoor unit heating thermostat ON, intake temperature
of the failure
temperature; and gas pipe temperature
(2) With the indoor unit cooling thermostat ON, gas pipe temperature
temperature; and gas pipe temperature
BS unit expansion valve failure; BS unit circuit board failure; piping clogged; SV failure;
Possible
causes indoor unit thermistor failure
of the failure
Flow chart
Is the stop valve open?
YES
Is the piping operating normally?
YES
Is the BS unit expansion valve
coil operating normally?
YES
Are the piping, wiring, and BS
unit board operating normally?
YES
Are SV3A-3F and SV31, 32
operating normally?
YES
Is the indoor unit thermistor
operating normally?
YES
Replace BS unit
163
continues for 6 minutes:
NO
Check stop valve
NO
Inspect piping
Inspect the BS unit
NO
expansion valve coil
NO Check wiring & power supply
Replace BS unit board
NO
SV inspection
Inspect indoor
NO
unit thermistor
gas pipe temperature
high pressure side saturation temperature.
liquid pipe temperature
high pressure side saturation temperature.
028040-00EN01
SiAUY361411EA
Error
LF
code
liquid pipe
intake
Troubleshooting