Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 238

Error definition and error
Error Code
4240 Overload pro- When the greater output
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
Refer to section -7- "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) Blocked air pathway
(3) Power supply
Imax
40 Arms
(4) Faulty wiring
50 Arms
(5) THHS failure
(6) Compressor INV board
failure and cooling fan fail-
ure
(7) Cooling failure
(8) Current sensor (ACCT)
failure
(9) Compressor INV board
cooling fan output failure
(10) Compressor failure
- 229 -
Cause Check method and remedy
Check that the waste heat from the
heat source unit fan is not short cy-
cled.
Check for a clogged air passage.
Check whether the power supply
voltage is 187V or more.
Check cooling fan wiring.
Check THHS1 sensor resistance.
Confirm that a voltage of 208/230V
is applied to the compressor INV
board connector CNFAN during in-
verter operation.
Check the cooling fan operation un-
der the above operating conditions.
Refer to 9 [4] -7- (4) "Current sen-
sor ACCT"
Refer to 9 [4] -7- (2) [4] "Check
whether the inverter is damaged"
Check that the compressor has not
overheated during operation.
->Replace the compressor when
no fault is found.
[ IX Troubleshooting ]