Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 258

Error definition and error
Error Code
4240 Overload pro- When the greater output
4245 tection current (Iac) than the
Imax (Arms), or THHS of
more than 90 °C [194°F]
is detected for 10 min-
utes in a row.
P72 model
P96 model
P108 model
P126 model
P144 model
P168 model
P192 model
P204 model
P216 model
P234 model
Refer to section -8-"Inverter " under part [4] "Trouble shooting principal parts" for error codes related to the inverter.
detection method
(1) Short cycle of the air pas-
sage
(2) Air passage blockage
(3) Power supply
Imax
(4) Faulty wiring
40 Arms
50 Arms
(5) THHS failure
50 Arms
50 Arms
53 Arms
(6) Compressor INV board
50 Arms
failure and cooling fan fail-
50 Arms
ure
50 Arms
53 Arms
(7) Cooling failure
53 Arms
(8) Current sensor (ACCT)
failure
(9) Compressor Inverter cir-
cuit failure
(10) Compressor failure
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Cause Check method and remedy
Check that the waste heat from the
outdoor unit fan is not short cycled.
Check that the heat sink cooling air
passage is not blocked.
Check whether the power supply
voltage is 187V or more.
Check for cooling fan wiring.
Check for THHS sensor resistor.
In the case of 4240: THHS1
In the case of 4245: THHS5
Check that a voltage of 208/230V is
applied to the compressor INV board
connector CNFAN while the inverter
is in operation.
Check the cooling fan operation un-
der the above operating conditions.
Refer to 9 [4]-8-(4).
"Current sensor ACCT"
Refer to 9 [4]-8-(2) [4].
"Check whether the inverter is dam-
aged".
Check that the compressor has not
overheated during operation.
-> Check the refrigerant circuit
(oil return section).
Replace the compressor
when no fault is found.
[ IX Troubleshooting ]