Century COMFORT-AIRE VMH-SG Series Service Manual page 108

Are the high pressure switch
Are the high pressure switch
and main control boar wired
and main control boar wired
Method: Disconnect the plug.
Method: Disconnect the plug.
Measure the resistance of the
Measure the resistance of the
high pressure protector, if the
high pressure protector, if the
protector is normal the value is
protector is normal the value is
o, Does a problem still exist?
o, Does a problem still exist?
temperature is higher than
temperature is higher than
Is the outdoor fan running
Is the heat exchanger dirty?
Is the heat exchanger dirty?
Replace outdoor main board. Is
Replace outdoor main board. Is
Check whether the refrigerant
Check whether the refrigerant
system is functioning properly
system is functioning properly
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.
High pressure protection
High pressure protection
correctly?
correctly?
Yes
Is the high pressure
Is the high pressure
protector broken?
protector broken?
Yes
Is the outdoor ambient
Is the outdoor ambient
50℃?
50℃?
No
Check if the outdoor unit
Check if the outdoor unit
ventilation is good
ventilation is good
Yes
Is the outdoor fan running
properly?
properly?
Yes
No
the problem resolved?
the problem resolved?
No
 Troubleshooting
Troubleshooting
Connect high pressure switch and
Connect high pressure switch and
No
mian control board
mian control board
Replace high pressure protector
No
Replace high pressure protector
Stop the unit
Yes
Stop the unit
Ensure that the outdoor unit
Ensure that the outdoor unit
NO
ventilation is functioning properly
ventilation is functioning properly
Please refer to the solution of the "Fan
Please refer to the solution of the "Fan
Speed is operating outside of normal
No
Speed is operating outside of normal
range"malfunction.
range"malfunction.
Yes Clean the heat exchanger
Clean the heat exchanger

Service Manual - VMHxxSG