Ground - Mitsubishi Electric City Multi PUMY-SP112VKM Technical & Service Manual

Check code
Superheat due to low discharge temperature trouble
1500
(U7)
Abnormal points and detection methods
Abnormal if the discharge superheat is continuously detected −15 [−27°F](*) or
less for 5 minutes even though the indoor LEV has minimum open pulse
after the compressor starts operating for 10 minutes.
LEV : Linear expansion valve
TH4 : Thermistor <Compressor>
63HS : High pressure sensor
*At this temperature, conditions for the abnormality detection will not be
satisfied if no abnormality is detected on either TH4 or 63HS.
●Diagnosis of defectives
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Is the TH4 wiring disconnected?
Check the resistance of TH4.
Is the resistance normal?
Check the connector contact and wiring of
the indoor LEV.
Is there any abnormality
such as a half-disconnection or
breakage?
Disconnect the indoor LEV wiring to check
the resistance.
Continue to the next page
OCH668B
Diagnosis
(disconnected)
(connected properly)
No
Yes
No
Causes and checkpoints
Disconnection or loose connection of TH4
Defective holder of TH4
Disconnection of LEV coil
Disconnection of LEV connector
LEV performance failure
Connect the wiring properly.
Yes
0 700 k"
10 · 410 k"
20 250 k"
30 160 k"
40 104 k"
No
Connect the connector properly,
Yes
or replace the LEV.
57
Chart 1 of 2
Remedy
Replace the TH4.