MXZ-SM36NAMHZ Service Manual

65
OCH789
Check code
1500
(U7)
Superheat due to low discharge temperature trouble
Abnormal points and detection methods Causes and checkpoints
If the discharge superheat is continuously detected −27°F [−15 ](*) 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
satised if no abnormality is detected on either TH4 or 63HS.
Disconnection or loose connection of TH4
Defective holder of TH4
Disconnection of LEV coil
Disconnection of LEV connector
LEV performance failure
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
..
Chart 1 of 2
32°F [0 ] ·········700k
"
50°F [10 ] ·····410k
"
68°F [20
]········250k
"
86°F [30 ] ·····160k
"
104°F [40
]·····104k
"
No
Yes
No
Yes
No
Yes
Is the TH4 wiring disconnected?
Is the resistance normal?
Is there any abnormality
such as half-disconnection or
breakage?
Connect the wiring properly.
Replace the TH4.
Connect the connector properly, or replace
the LEV.
Check the resistance of TH4.
Check the connector contact and wiring of
the indoor LEV.
Disconnect the indoor LEV wiring to check
the resistance.
(disconnected)
(connected properly)
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