Mitsubishi Electric FDT125VNVF Technical Manual page 343

(a) Cautions
(b) SRK series
1) If you are disassembling and checking an air conditioner, be sure to turn off the power before beginning.
(ⅰ) Cautions
When working on indoor units, let the unit sit for about 1 minute after turning off the power before you begin work.
1) If you are disassembling and checking an air conditioner, be sure to turn off the power before beginning.
2) When taking out printed circuit boards, be sure to do so without exerting force on the circuit boards or package components.
When working on indoor units, let the unit sit for about 1 minute after turning off the power before you begin work.
3) When disconnecting and connecting connectors, take hold of the connector housing and do not pull on the lead wires.
2) When taking out printed circuit boards, be sure to do so without exerting force on the circuit boards or package
components.
(b) Items to check before troubleshooting
1) Is the air conditioner running? Is it displaying any self-diagnosis information?
3) When disconnecting and connecting connectors, take hold of the connector housing and do not pull on the lead wires.
2) Is a power supply with the correct voltage connected?
(ⅱ) Items to check before troubleshooting
3) Are the control lines connecting the indoor and outdoor units wired correctly and connected securely?
1) Is the air conditioner running? Is it displaying any self-diagnosis information?
4) Is the outdoor unitÕ s service valve open?
2) Is a power supply with the correct voltage connected?
3) Are the control lines connecting the indoor and outdoor units wired correctly and connected securely?
(c) Troubleshooting procedure (If the air conditioner does not run at all)
If the air conditioner does not run at all, diagnose the trouble using the following troubleshooting procedure.
4) Is the outdoor unit
When all the following conditions are met, we say that the air conditioner will not run at all.
Important
(ⅲ) Troubleshooting procedure (If the air conditioner does not run at all)
1) The RUN light does not light up.
If the air conditioner does not run at all, diagnose the trouble using the following troubleshooting procedure.
2) The f laps do not open.
When all the following conditions are met, we say that the air conditioner will not run at all.
Important
3) The indoor unit fan motors do not run.
1) The RUN light does not light up.
4) The self-diagnosis display does not function.
2) The f laps do not open.
3) The indoor unit fan motors do not run.
4) The self-diagnosis display does not function.
Troubleshooting procedure (If the air conditioner does not run at all)
Is the correct voltage
connected for the power
supply?
With the power off, do
the ßaps open manually,
then close again when
the power is turned on?
Replace the indoor printed
circuit board and perform an
operation check.
,
s service valve open?
Make sure the correct volt-
NO
age is connected, then per-
form an operation check.
YES
NO
YES
Proceed to the indoor printed
circuit board check.
Is the current fuse on the in-
door unit , s board broken?
NO
342
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'12 • PAC-T-174
* If the voltage is correct, it will be
within the following voltage range.
198 ~ 264 V
YES
If the package components
are not damaged, replace
the fuse and perform an op-
eration check again.