This can present a problem due to the automatic reset controls found on most residential and light commercial units. During a malfunction, a control opens and stops the unit’s operation. By the time you drive across town, the safety control has time to reset.
Flagging is done. Flags are sold at most supply houses. Let me explain to those that might never have used them. The flag is designed to conduct very small amounts of electricity. It will open like a fuse if a high ampacity load is placed across it. The flags are wired across every control in parallel. In the event the control opens, the flag will open and indicate. I’ve found that small ampacity type automotive fuses and holders work as well and are less costly. When flagging a unit, don’t place flags on controls that are supposed to open such as the low pressure control of a pump-down system. Only flag the actual safety controls. With the use of this method, you at least find out what part of the system is the problem area.