This job was located in signal Hill California. It was to help out someone I know personally.
Fixing any kind of factory equipment can be a huge pain. Even more so when its 100 degrees and the competent repair people are booked 3 weeks out while you are sweating in your office. I have helped repair multiple hvac units because during the busy season HVAC companies send out less qualified crews trying their best to help the inevitable flood of calls that comes in.
However these extra crews really can only check the basics and will often leave by recommending you replace the unit completely. However most situation are fixable and many are even fixable by someone with just a little competence and electrical tools. Rarely do units leak and loose refrigerant. Most often the problems are poor maintenance or an electrical issue.
In this case the control panel was completely off so I did the following step by step procedure used for fixing any heat pump that is not responding.
I removed the thermostat and checked for batteries. There were none and I searched online to determine that it will shut off with out a hardwired power supply. I checked the power at the terminals behind the thermostat and there was none.
Next I went to the breaker. It was on and appeared to be supply power. Next I went to the rooftop unit.
The unit has a disconnect and usually a breaker of fuse as well. I check the power coming in and leaving the breaker. If you are using a non contact tester at this point you must stop and use a multiplier.
Now I began checking the power as it moved through the unit. The power splits up and does multiple things in the unit so I think logically and go to the 24v transformer supplying power to my thermostat. Its only showing 1 volts. Not the 24 I need. So I run down to the supply house and grab a 24v 60va transformer.
As soon as the transformer is installed I switch the equipment back on and everything is working. Naturally I check the air filter and inside compartment for dust and debris to eliminate stress on the unit.
You will notice I have a very linear logic of fixing the simplest items such as checking for power at the thermostat then checking for power at each point. I have successfully fixed several heatpump issues where another company has recommended replacement. This is not for the amateur however and requires skill in understanding as well as safe practices in working with high voltage equipment.