What Happens During an A/C Maintenance Inspection of Your Air Conditioning System
When we talk about inspections it starts with the office. They call to confirm that the customer is home and the approximate arrival time of the technician. When the technician arrives he should be in uniform to identify himself and the company, He then should ask for the location of the equipment and if they are having any particular problem that they can look at during the inspection. Now for the inspection!
He sets the thermostat on cooling or heating depending on the mode of operation they want so they can check out system running conditions.
Check return air filter or filters, this is based on return air duct design and if they are clogged you can not not get the proper readings needed to diagnose the system.
Wash out outside condenser coil with garden hose. This is done because dirt and grass clippings accumulate on the coil causing blockage to airflow and shorting the life of your equipment.
While disassembling the outside unit, the technician is checking wiring, capacitors, contactors, connections for wear and tear and all around condition of unit, that is any rusting, oil spots that could identify a problem starting.
After he puts the unit back together, he checks the outside disconnect for burnt wiring and poor electrical connections.
The technician then goes to the inside unit and checks condition of evaporator coil and drain pan for a dirty coil that might have algae build up on it or mold. He also looks for those same conditions in the drain pan. The reasoning for this is that in Alberta you have very high humidity and with the cold temperature of the evaporator coil making moisture (condensate) it lends itself to producing mold. Which can cause allergies, eye irritation and possible asthma attacks. He then cleans out the drain line adds algaecide tablets in drain pan to reduce the chance of algae clogging up your drain line.
While unit is open he also checks wiring, capacitor, relays and contactors. Makes sure blower wheel is clean because if it is not clean it reduces air flow shorting the life of your equipment. He then looks for any rusting and oil spots that could identify a problem starting.
After he puts unit back together he checks the inside disconnect for burnt wiring and poor electrical connections.
Now that both sections are together and there isn't anything that we know of restricting air flow we can check the operation of the air conditioning and heating system.
We then check amperages of the compressor and fan motors. The auxiliary heat strip of a Heat Pump, the heat strips of a Straight Cool with Electric Heat. With Gas Furnaces we check ignition, burner, flame, controls and safety controls. With Oil Fired Furnaces we check oil filter, oil pump ignition, flame, controls and safety controls.
Now unit has stabilized we check refrigerant pressures based on refrigerant charts that show what the pressures should be depending on the metering device. Expansion valves we use the sub cooling method and with flow control orifices we use the super heat method.
Now that the unit has been diagnosed a report is filled out with the items checked and any recommendation that would be needed to bring unit up to proper operating condition and provide the most energy efficiency. I hope this helps you in understanding what goes on when you are having your Air Conditioning and Heating system serviced. Have a reputable company service your unit. Ask a friend or relative who has had good service or the BBB or homestars because these are good third party advocates.