|Alarm meaning||Low-pressure switch activated|
A report occurs during A/C operation when the low-pressure sensor installed at constant low-pressure parts detects a pressure of 0.05 MPa or less continuously for 2 minutes, or an instantaneous pressure of 0.02 MPa or less. (These values represent abnormal low pressure which may damage the compressor.)
However, the alarm does not actually occur the first 2 times that the above operation takes place. At these times, the outdoor unit is stopped and the conditions are monitored. The alarm occurs when the above operation occurs for the fifth time. The first 4 times before the alarm occurs are called “pre-trip.” After pre-trip occurs, if the low-pressure sensor detects a pressure of 0.15 MPa or more for 3 minutes of continuous operation, the pre-trip count is reset to 0.
If the low-pressure sensor detects a pressure of 0.16 MPa or less continuously for 30 minutes when the compressor is stopped, an alarm occurs immediately (no pre-trip).
|Probable cause||The A/C unit low pressure has dropped to a level that does not occur under ordinary conditions.