Hitachi Econofresh, Service Manual

Page: 373 / 408

11.2 Electronic expansion valve
1 Check that the voltage of the valve ranges between 12Vdc
±1.2V.
2 Use a multimeter to check the coil resistance (per phase). This
ranges between 150
Ω
±10% at an ambient temperature of 20°.
3 Check the number of pulses per second. This ranges between
100
Ω
± 250 pulses per second (the width between pulses is
greater than 3 mm ) on activating phase 2.
4 Check that the valve flow is reversible.
5 When the valve is fully open and in heating process, check that
the temperature of the liquid in the piping increases. If not, this
indicates a fault.
6 When the valve is slightly open or fully open, check that the
temperature of the freeze protection thermistor is higher than
the suction temperature. If not, this indicates a fault.
11 Electrical checks of the
main parts
361
SMGB0063 rev. 1 - 10/2010
11