Pressurized system to 200 psi with nitrogen and a little bit of trace gas to find out where the leak is coming from in the Refrigeration circuit with an electronic leak sniffer Arrived to find a system from 1999, which is 26 years old. System contains HCFC 22 Which has been removed worldwide by the EPA for use on air-conditioning systems due to the toxicity of the gas. There is a drop in refrigerant that is compatible that the EPA allows which is R 407C Typical systems last 16 to 20 years gas company recommends 25 years to replace your heater due to the potential safety hazards of the internal heat exchanger firebox that could have carbon monoxide leaks Due to the age overall condition of the system and potential safety hazards recommending replacing the entire system for the occupants in the home. New systems come with 10 year warranties are quieter and ,ore efficient on the utility bills.