Mitsubishi Heavy Industries FDT100VNAWVH Service Manual page 63

(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
3) When disconnecting and connecting connectors, take hold of the connector housing and do not pull on the lead wires.
begin work.
(b) Items to check before troubleshooting
2) When taking out printed circuit boards, be sure to do so without exerting force on the circuit boards or
1) Is the air conditioner running? Is it displaying any self-diagnosis information?
package components.
2) Is a power supply with the correct voltage connected?
3) When disconnecting and connecting connectors, take hold of the connector housing and do not pull on
3) Are the control lines connecting the indoor and outdoor units wired correctly and connected securely?
the lead wires.
4) Is the outdoor unitÕ s service valve open?
(ii) Items to check before troubleshooting
(c) Troubleshooting procedure (If the air conditioner does not run at all)
1) Is the air-conditioner running? Is it displaying any self-diagnosis information?
If the air conditioner does not run at all, diagnose the trouble using the following troubleshooting procedure.
2) Is a power source with the correct voltage connected?
When all the following conditions are met, we say that the air conditioner will not run at all.
Important
3) Are the control lines connecting the indoor and outdoor units wired correctly and connected securely?
1) The RUN light does not light up.
4) Is the outdoor unit
2) The flaps do not open.
(iii) Troubleshooting procedure (If the air-conditioner does not run at all)
3) The indoor unit fan motors do not run.
If the air-conditioner does not run at all, diagnose the trouble using the following troubleshooting procedure.
4) The self-diagnosis display does not function.
Important
Troubleshooting procedure (If the air-conditioner does not run at all)
Is the correct voltage
connected for the power
source?
With the power off, do
the f laps 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?
When all the following conditions are satisfied, we say that the air-conditioner will not run at all.
1) The RUN light does not light up.
2) The flaps do not open.
3) The indoor unit fan motors do not run.
4) The self-diagnosis display does not function.
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
62
- -
'19 • PAC-SM-309
* If the voltage is correct, it will be
within the following voltage range.
AC198 - 264V
YES
If the package components
are not damaged, replace
the fuse and perform an op-
eration check again.