Daikin Sensira Series Service Manual page 55

To perform an operation check of the expansion valve
FTXF20~71A + FTXF20~25B + FTXF20~42C + ATXF20~71A + ATXF20~42C
+ RXF20~71A + RXF20~60B + RXF20~42C + ARXF20~71A + ARXF20~42C
Split Sensira R32
ESIE18-12E – 2021.02
a Connector
3 Check the insulation resistance of the coil by measuring the resistance
between the pins of each phase (1, 2, 3, 4) and GND on the unit.
Result: None of the measurements should be short‑circuit.
WARNING
When reconnecting a connector to the PCB, make sure to connect it on the correct
location and do NOT apply force, as this may damage the connector or connector
pins of the PCB.
Is the measured resistance correct?
Yes
No
Prerequisite: First perform an electrical check of the expansion valve, see
"2.3.1 Checking procedures" [
1 Turn ON the power of the unit.
INFORMATION
When power is switched ON, PCB checks all expansion valve coil windings by current
check. If winding is short or open, expansion valve error is triggered.
2 Start the unit operation via the user interface.
3 With the unit operating, connect the service monitoring tool to the unit.
4 When the expansion valve is closed according to the service monitoring tool,
check the inlet and outlet of the valve with a contact thermometer or use an
expansion valve stethoscope to see if refrigerant flows through the expansion
valve. Check that the valve is NOT bleeding.
Result: There MUST be NO flow through the expansion valve.
5 When the expansion valve is open according to the service monitoring tool,
check the inlet and outlet of the valve with a contact thermometer or use an
expansion valve stethoscope to see if refrigerant flows through the expansion
valve.
Result: Refrigerant MUST flow through the expansion valve.
6 Wait for the PCB to command the expansion valve to open (when closed) or to
close (when open) (pulse output to expansion valve visible on service
monitoring tool).
INFORMATION
If the PCB does NOT command the expansion valve to open or close (when it is
supposed to), perform a check of the appropriate thermistors and pressure sensors
(expansion valves are driven by superheat or subcool value calculated through the
thermistors).
7 While in opening or closing sequence each expansion valve winding (Ф1, 2, 3,
4) is supplied with 12 V DC from the PCB. You will need a good multimeter,
where its range is set to about 20 V DC, and during opening or closing
Action
Perform an operation check of the
expansion valve, see
procedures" [
Replace the expansion valve coil,
"2.3.2 Repair
4
53].
2 Components
|
"2.3.1 Checking
4
53].
4
procedures" [ 56].
Service manual
55