Called out today due to no cooling. Upon arrival system was tripped on the float switch causing the thermostat to go blank. I gave options for a chemical drain cleaning due to the visible algae build up. Evaporator coil is heavily impacted. After pulling the float switch I checked all electronics and motor components to ensure equipment is operating properly within manufacture specifications. Checked filter. Measured the temperature drop across the coil (which was 2.3 degrees…..) Went to the roof and checked refrigerant pressures. System was extremely low on R22 refrigerant. Compressor ratio was 6.1. I explained to the clients that to resolve this issue we would need to perform a leak search, find the leak, fix the leak and then refill the system of refrigerant. R22 has not been manufactured since January of 2020… we as a company do not carry it anymore. Bare minimum for the cost of this refrigerant leak repair would be around 2,000. Due to the age, condition and warranty status