Faults that only appear occasionally are among the most difficult to diagnose, because they may not be present when the technician arrives.
1. Alarm history
Record which fault appeared first and at what time.
2. Trends
Monitor temperatures, pressures, flow, compressor frequency and electrical values.
3. Occurrence conditions
Correlate with outdoor temperature, defrost, DHW or load changes.
4. Wiring and contacts
Check for loose connections, plugs and intermittent communication faults.
5. Reset
Perform a reset only after data has been recorded, so that information needed for the actual cause is not lost.
