Century COMFORT-AIRE VMH-SG Series Service Manual page 101

Service Manual - VMHxxSG
TS08-S: Current overload protection diagnosis and solution
Description: An abnormal current rise is detected by checking the specified current detection circuit.
Recommended parts to prepare:
• Connection wires
• Reactor
• Outdoor fan
• Outdoor PCB
Troubleshooting and repair:
Was the protection activated
Was the protection activated
Is the power voltage is normal?
Is the power voltage is normal?
Is outdoor terminal voltage
Is outdoor terminal voltage
Is the voltage between L and N
Is the voltage between L and N
Power on and measure the
Power on and measure the
While the unit is in standby,
While the unit is in standby,
is the voltage between P and N
is the voltage between P and N
is around DC 310V, 340V or
is around DC 310V, 340V or
380V? When start up the unit,
380V? When start up the unit,
temperature is higher than
temperature is higher than
Is the outdoor fan running
Is the outdoor fan running
Is the heat exchanger dirty?
Is the heat exchanger dirty?
board. Does a problem still
board. Does a problem still
Is system pressure too high?
Is system pressure too high?
Check whether the refrigerant
Check whether the refrigerant
system is running normally
system is running normally
Note: For certain models, outdoor PCB could not be removed separately. In this case, the outdoor electric
control box should be replaced as a whole.
in standby?
in standby?
No
No
Yes
No
normal？
normal？
Yes
No
is normal？
is normal？
Yes
Is the current normal？ Yes
Is the current normal？
No
voltage between P and N.
voltage between P and N.
is it in 220V~400V?
is it in 220V~400V?
Yes
Is the outdoor ambient
Is the outdoor ambient
Yes Stop the unit
50℃?
50℃?
No
Is the outdoor unit
Is the outdoor unit
Ensure that the outdoor unit ventilate
Ensure that the outdoor unit ventilate
ventilation functioning No
ventilation functioning
properly?
properly?
Yes
Please refer to the solution of the
Please refer to the solution of the
No "fan speed is operating outside of
"fan speed is operating outside of
properly?
properly?
the normal range" malfunction.
the normal range" malfunction.
Yes
Clean the heat exchanger
Yes Clean the heat exchanger
No
Replace outdoor main
Replace outdoor main
exist?
exist?
Yes
Recycle the overcharged
Recycle the overcharged
Yes
No
 Troubleshooting
Restart the unit when the power supply
Restart the unit when the power supply
returns to normal
returns to normal
Is the power wiring Reconnect the
Is the power wiring Reconnect the
wired correctly? power wiring
wired correctly? power wiring
Are L and N wired
Are L and N wired
Reconnect L and N
Reconnect L and N
properly?
properly?
Replace the outdoor main PCB
Replace the outdoor main PCB
Is the wiring of the
Is the wiring of the
No
reactor properly wired?
reactor properly wired?
Yes
Stop the unit
Are the reactor and
Are the reactor and
inductance functioning
inductance functioning
normally
normally
is working properly
is working properly
Yes
refrigerant
refrigerant

Troubleshooting
Yes
No Reconnect the wiring
Reconnect the wiring
No Replace reactor
Replace reactor