Solution method: After replacing the connection, the fault was eliminated. Article source: Beijing Sharp Air Conditioner Repair Phone http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3766461. Analysis and maintenance: The control circuit of this machine uses the microcomputer chip uPD75028 as the main controller. Its heating instruction is issued from pin 60 of the chip, so it is necessary to focus on checking whether there is a high-level output at pin 60 of the chip, whether the resistance value of the indoor sensor is normal, and whether there is 220V voltage between the blue line in the outdoor unit wiring and the green line in the signal line. After inspection, it was found that there was no 220V voltage across the solenoid valve coil terminals in the outdoor unit wiring. Upon opening the indoor unit circuit board, it was measured that there was 220V voltage between the output terminal of the solenoid valve control relay and the L terminal of the power wiring, indicating a fault in the signal line. Further checks revealed signs of damage to the wiring at the pipe bend where the indoor unit tubing passed through the wall, and it was discovered that the solenoid valve control line (green) had an open circuit.
Sharp 1P heat pump air conditioner, unable to provide heating.
Fault phenomenon: The compressor operates normally for cooling but does not provide heating.