Superheat Due To Low Discharge Temperature Trouble - Mitsubishi Electric PUMY-P112VKM1 Service Manual

Check code

Superheat due to low discharge temperature trouble

1500
Abnormal points and detection methods
Abnormal if the discharge superheat is continuously detected less than
or equal to −15 [5°F]* for 5 minutes even though the indoor LEV has
minimum open pulse after the compressor starts operating for 10 minutes.
LEV : Electronic 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
OCH576
Diagnosis
(disconnected)
No (connected properly)
Yes
No
Causes and check points
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.