Pioneer QUANTUM INVERTER Series Service & Troubleshooting Manual page 141

High pressure protection
Are the high pressure switch
and main control board wired
correctly?
Yes
Is the high pressure
protector defective?
Method : Disconnect the plug.
Measure the resistance of the
high pressure protector. If the
protector is normal the value is
0. Does a problem still exist ?
Yes
Is the outdoor ambient
temperature higher than
122°F ?
No
Check if the outdoor unit
ventilation is good
Yes
Is the outdoor fan running
properly ?
Yes
Is the heat exchanger dirty ?
No
Replace outdoor main board .
Is the problem resolved?
No
Check whether the refrigerant
system is functioning properly
Troubleshooting

Connect high pressure switch
No
and main control board
No Replace high pressure protector
Yes Stop the unit until temps drop
Ensure that the outdoor unit
NO
ventilation is configured properly
Please refer to the solution of the
"Fan Speed is operating outside of
No
normal range" malfunction.
Yes Clean the heat exchanger
33