Haier HBU-18HF03 Manual page 239

minutes later after it is powered on again
4.7 Sensor broken down protection
a. Check if sensor breaks down
After compressor has run for 2 minutes, the unit will check the sensor, Outdoor board checks
the sensor in short circuit or in open circuit or near to short/open circuit for 2 minutes continuously,
then it will adjust the sensor broken down.
b. How to deal with it?
If the outdoor ambient temperature sensor and the outdoor coil temperature sensor have
broken down, the unit will stop running, and alarm E3, E4, E4 simultaneously.
4.8 Starting current control
Outdoor unit load control: after the outdoor motor running for 2 seconds, main compressor start
up, the secondary compressor will run 2 seconds later.
4.9 4-way valve control
5. Outdoor PCB test
(1) There are three pins marked with TEST, please make the two ones near to COOL in short circuit.
Outdoor begin to run in cooling mode, that is, compressor run and outdoor motor works at high
speed.
(2) There are three pins marked with TEST, please make the two ones near to HEAT in short circuit.
Outdoor begin to run in heating mode, that is, compressor and 4-way valve run, outdoor motor
works at low speed.
Electric control functions
-239-