Tom M. 12-8-24 No heat customer stated the system has been blowing cold air now the thermostat is blank. Found 30 amp breaker tripped to the air handler. Reset the breaker. Power on y for a call for heat but no power on r to power the defrost board. Noticed the R not connected on the air handler going to the heat pump. Customer stated he was told it was too cold to charge the heat pump during recent install. While checking the charge the system shut down again. Went to the air handler it has high voltage, high voltage going to the transformer and nothing coming out. Noticed a burn mark inside the mulex plug, high voltage wires feeding the air handler at the breaker were extremely loose. I did not have another transformer to replace will contact customer tomorrow to schedule a return trip. Before the system stopped again I noticed the outdoor coil freezing also it did not seem the blower motor did not seem to be producing enough air flow.