Norm Christopherson
With the heating season winding down and the cooling season soon upon us, it is time to reconsider what is involved in proper cooling system maintenance. Perhaps each contractor or service manager should hold a short but useful meeting reminding all technicians of what is involved in providing customers with professional preseason air conditioning service and why we do them.

Even while technicians continue to service heating systems, it is a good idea to start thinking about preseason cooling service. Technicians can begin reminding customers of the need for servicing their air conditioning systems before the warmer weather arrives. Just as we prepare our automobiles in the fall prior to winter's freezing temperatures, air conditioning systems need to be prepared for the hot summer conditions.

Customers can be reminded of the following reasons preseason service needs to be performed. However, all of us in the business need to remind ourselves as well.

  • Lower operating cost

    Even a film of residue on the coil and fins of the condenser will raise the high side pressure and decrease heat transfer to the point of increasing running time and decreasing compressor efficiency. Reciprocating compressors operating with even a slightly increased high side pressure lose effective stroke rapidly, thus increasing power consumption. Excessive high side pressure is trapped in the clearance pocket of a reciprocating compressor at the end of the compression stroke. This trapped pressure must re-expand on the down stroke before the suction valve can open to draw in new refrigerant from the low side. The higher the high side pressure, the farther the piston must fall on the suction stroke before the suction valve opens. This can amount to a substantial loss in pumping capacity.

    In addition to the loss in capacity, the compressor is consuming more power as it works against the higher high side pressure. Just cleaning a dirty condenser can increase capacity by 20 percent or more while decreasing operating cost by 15 percent or more, depending upon how much the high side pressure is lowered.

  • Increased operating capacity

    This has already been discussed in the last item but bears repeating. Cleaning condensers really does make a substantial difference in improving system efficiency. This fact is so important to understand that I intend to discuss it in some detail in a future article.

  • Reduced possibility of a system failure

    Properly servicing a system will reduce the possibility of a problem during the summer. Just cleaning the condenser and lowering the high side pressure will decrease the stress on the system. Additional items rectified during the preseason check may eliminate other potential problems.

    For example, vibrating copper lines, lines in contact with each other, or in contact with the cabinet could become leaks. Loose electrical connections could become the cause of other problems.

  • Increased comfort level

    A clean system operating at its rated capacity and airflow will provide the greatest possible level of comfort. A clean evaporator coil with good airflow will allow for better humidity control.

  • Improved indoor air quality

    With the new awareness for the necessity of improved indoor air quality in our homes and workplaces, we need to stress the importance of keeping cooling systems clean. All technicians have serviced residential systems that were incredibly dirty. So dirty, in fact, that they were disgusting to work on. Considering that the air we breathe has been transported through this filth, it should not be difficult to convince customers of the need to clean their units. I like to actually show my customers their systems while I have them apart and let them see for themselves. That alone often sells the customer on a contract for regularly scheduled service.

    There are also advantages to the contractor and technician:

  • Increased income

    This is pretty obvious. Preseason service brings in more work and added income.

  • Technicians remain busy

    Preseason service can be scheduled to be performed during slower times of the week or month, whereas emergency service cannot.

  • Customer relations

    Unlike emergency service calls, technicians can take more time to discuss the operation and maintenance of the system with the customer. Actually showing the customer the dirt flowing out of the condenser while washing it out is pretty strong evidence to the customer of the need to regularly service the system. Technicians who take the time to communicate with their customers are building trust for a continued business relationship.

  • Potential for sales leads

    Preseason service is not only a good time to increase system efficiency, increase comfort, decrease the operating cost, and reduce the potential for future problems, but it is also a time to build customer trust and begin planting the seed for a future replacement sale. Even an older, well maintained 8 SEER system is a candidate for an upgrade to a new 12, 14, 16, or better replacement.

    When given the scoop on the potential for energy savings with a new higher SEER system, some customers are ready to make the upgrade. Many customers are more comfortable with their technician than with a salesperson, so preseason service is also an opportunity for a sale.

  • Sale of service contracts

    Once a customer actually sees the dirt removed from their system and the technician actually takes the time to discuss how the preseason service benefits them, the potential for the sale of a service contract is much greater. Good technician communication with the customer is key.

    Each technician should take time to learn these customer benefits and be prepared to clearly explain them to each customer on every call. Remember, even the heating service calls we get are ideal opportunities to sell customers on preseason air conditioning service.

    What Does Preseason A/C Service Consist Of?


  • Check the location of the thermostat. The thermostat should be approximately 5 feet above floor level on an inside wall, not near a supply register, and not where the sun's radiant heat affects it. The thermostat should be level, especially if it is a mercury bulb type. The hole in the wall where the thermostat wires enter should be sealed up to prevent wall drafts from reaching the thermostat.

  • Inspect the electrical wiring for missing insulation and brittle or discolored insulation. Replace as necessary.

  • Check all electrical connections for loose terminations. Also carefully check each electrical termination for signs of overheating and discoloration.

  • Make sure the filter is clean, the right size and type, and that it properly fits the filter rack.

  • Check the blower and blower motor for dirt and clean as necessary. The blower assembly must usually be removed and taken outside for proper cleaning. Even a small amount of dirt on the blades of a blower will decrease the airflow enough to make a difference in system operation.

  • Lubricate the blower motor as necessary. Use the proper oil (not a penetrating oil) and do not over-oil. Many blower motors have sealed bearings and are not to be oiled.

  • Inspect the evaporator coil for an accumulation of dust, dirt, lint, pet hair, or other accumulation and clean as necessary. I clean evaporators by first removing as much material as possible using a short stiff dog brush and then follow up with a suitable chemical evaporator cleaner spray. Follow the directions on the liquid evaporator cleaner bottle.

  • Inspect all accessible ductwork and connections for crushed or damaged ducts and leaking or separated connections.

  • Make sure all supply registers are open and not obstructed by rugs, furniture, or other objects. Do the same for the return grilles. Check the number and location of return grilles. Many homes do not have enough return grilles; they are too small and are poorly located.

  • Clean the evaporator condensate drain. Make sure a condensate trap is installed.


  • Check for proper clearance between the condensing unit and the house.

  • Examine the condenser for dirt, leaves, cottonwood seeds, weeds, and any accumulation in general. Clean the coil even if it looks clean. Notice the amount of dirt that is washed out of even a clean looking coil.

  • Check the area for obstructions to the airflow through the condenser. Are trees or the overhang of the roof obstructing the upward airflow of the condenser discharge air? Are bushes or plants obstructing the intake of air to the condenser?

  • Check to see if the roof overhang allows rainwater or melting snow from the roof to drip directly onto the condensing unit.

  • Open the outdoor electrical section and clean out all cobwebs, insects, or other accumulation of dirt and dust.

  • Inspect the electrical wiring for missing insulation and brittle or discolored insulation. Replace as necessary.

  • Check all electrical connections for loose terminations. Also carefully check each electrical termination for signs of overheating and discoloration.

  • Carefully look over any run or start capacitors for signs of overheating.

  • Inspect the electrical contacts on the compressor contactor for discoloration, contact pitting, and excessive wear. Recommend a replacement if your inspection determines the contactor is ready for replacement.

  • Check for missing or deteriorated insulation on the suction line and replace as necessary.

  • Check the system charge using the correct method for the type of system and metering device used by the system.

    This checklist is general in nature and may be modified to match the type of equipment serviced.

    Before You Leave

  • The technician should record all his or her inspection findings on the service work order. This allows the customer to see what was accomplished, it gives the technician a record if questions arise later, and the service manager is able to refer to the record should the customer question what was accomplished or question the recommendations of the technician for additional work.

  • Talk to the customer and explain the results of the preseason service. If the preseason service turned up any additional items that should be addressed, explain them to the customer and offer to take care of them immediately or make an appointment to return soon.

  • This is also a good time to offer the customer a service contract. If the customer actually watched the technician cleaning the system and saw the dirt washing out of the condenser, or saw dirt and pet hair removed from the evaporator, a service contract sale is much easier.

  • Make absolutely sure you leave the home and your work area as clean, or even cleaner, than when you arrived.

    Note: Contractors or service managers should use this article as a guide for one of your service meetings with your technicians. Do so now before the warm weather arrives and before the summer heat has you too busy servicing air conditioning systems to even hold a service meeting.

    Norm Christopherson is a former HVACR instructor, a technical writer, and a seminar presenter. He is currently seeking seminar and training opportunities. He can be contacted at

    Publication date: 04/05/2004