Maintaining Air Conditioners

During summer, outside temperature reaching to near 40°C can be very irritating. Worst case if your air conditioner at home is not giving you the ample coolness the way it used to be. This problem is mostly encountered by people neglecting the proper maintenance procedure or simply neglect of doing it themselves. You have nothing to blame but yourself. But before you pick up that phone and start calling your repair man to do the maintenance for you, why not read further below and check if the recommended maintenance procedure would be beneficial and is easy to follow. Here are some very basic steps on how to maintain your air conditioning unit. This procedure can be applied to all standard window-type as well as standard split-type air conditioner units.

Precaution: Before doing any maintenance, switch off the main circuit breaker of the air conditioning unit on disconnect the air conditioning unit from the electrical outlet during maintenance.

Cleaning of air filters of split and window-type air conditioning units.

1. Switch off the air conditioning unit.
2. Gently pull out the air filter from the air conditioning unit.
3. Clean the air filter using a vacuum cleaner.
4. If the air filter is very dirty, wash it with clean water and neutral detergent (soft brush shall be used to effectively remove the dirt).
5. Dry the air filter using a soft cloth / rags.
6. Return the air filter to the air conditioning unit.
7. Switch on the air conditioning unit if necessary.
8. This procedure shall be done every 2 weeks.

Cleaning of evaporator and condenser coil of split type air conditioning units.

1. Remove and recover refrigerant from the air conditioning unit using refrigerant recovery equipment. (refer to procedure 5)
2. Disconnect the power supply, refrigerant lines, and drain lines from the evaporator Unit (indoor unit) and condensing unit (outdoor unit).
3. Evaporator and condensing unit shall be pulled out and place in a containment pan.
4. Fan impeller and casing (if any) of evaporator unit (indoor unit) and condensing Unit (outdoor unit) shall be dismantled and washed using clean water and neutral detergent or water soluble solution.
5. Fan motors of indoor and outdoor unit shall be dismantled (if possible) to prevent it from being damaged during coil cleaning.
6. All electrical components including fan motors of evaporator and condensing unit shall be covered with plastic or any water resistant material.
7. Rinse the evaporator and condenser coil with the manufacturers approved chemical coil cleaner (approximately 2.5 to 3 liters per TR cooling capacity).
8. Rinse the evaporator and condenser coil with sufficient water to remove the dirt and the chemical coil cleaner. Contaminated water collected in the containment pan should be disposed properly.
9. Clean the casing (indoor and outdoor unit) and air diffuser (indoor unit only) with soft cloth or rag. Use clean water and neutral detergent if dirt and stain are difficult to remove.
10. Assemble all dismantled parts of the evaporator and condensing unit.
11. Drain line of indoor unit shall be flushed with the manufacturers approved liquid de-clogger (approximately 100 to 200 ml) and clean water sufficient enough to remove the clog materials. (Contaminated water from this procedure should be disposed properly.
12. All refrigerants and drain line connections to the air conditioning unit shall be leak tested using nitrogen and water respectively as medium. (Soap solution shall be applied to refrigerant line connections to easily locate the leaks).
13. Prior to refrigerant charging, refrigerant lines shall be subjected to flushing using nitrogen gas.
14. Prepare and charge the unit with applicable refrigerant by Triple Evacuation Method.(refer to procedure 6).
15. This procedure shall be done semi annually (every 6 months).

Cleaning of evaporator and condenser coil of window type air conditioning units.

1. Air conditioning unit shall be pulled-out and place in a containment pan.
2. Fan impellers for evaporator and condenser coil shall be dismantled and washed with clean water and neutral detergent or water soluble solution.
3. All electrical components including fan motor shall be covered with plastic or any water resistant material.
4. Rinse the evaporator and condenser coil with manufactures approved chemical coil cleaner (approximately 2.5 to 3 liters per TR cooling capacity).
5. Rinse the evaporator and condenser coil with sufficient water to remove the dirt and chemical coil cleaner. Contaminated water collected in the containment pan shall be disposed properly.
6. Clean the casing and air diffusers using a soft cloth / rag. If dirt and stains are difficult to remove, wash it with clean water and neutral detergent or water soluble solution.
7. Assemble all dismantled parts of the air conditioning unit.
8. Drain line of the air conditioning unit shall be flushed with manufacturers approved liquid declogger (approximately 100 to 200ml) and clean water sufficient enough to remove the clog materials. Contaminated water from this procedure shall be contained and disposed properly.
9. Drain line connection shall be leak tested using water.
10. This procedure shall be done quarterly (every 3 months).

Replacement of Filter Dryer

1. Filter Dryer of split-type air conditioning units shall be replaced annually.
2. Replacement of the said element shall be done during the cleaning of evaporator and condensing unit.
3. Filter Dryer of air conditioning shall be replaced during breakdown maintenance.
4. Filter Dryer connections shall be leak tested as per procedure 2.

Recovery of Refrigerant

1. Prepare the refrigerant recovery equipment and one (1) empty cylinder tank of refrigerant.
2. Connect the refrigerant recovery equipment to the charging port of the Condensing unit. Likewise, Refrigerant Recovery Equipment shall be connected to the empty cylinder tank of refrigerant.
3. Start the Refrigerant Recovery Equipment. By-pass the lower pressure switch of the air conditioning unit by manual pressing of magnetic contactor during refrigerant recovery to prevent the compressor to stop due to low pressure refrigerant. Release the magnetic contactor when the refrigerant pressure on the gas line drops to 10 psig.
4. Close the valve of the refrigerant tank and stop the Refrigerant Recovery Equipment.

Preparation of Refrigerant line and charging of Refrigerant by Triple Evacuation Method

1. Connect the gauge manifold to the refrigerant lines.
2. Purge all pressure from the refrigerant lines by opening the system service valves and gauge manifold hand valves.
3. Connect the center hose of the gauge manifold to the vacuum pump.
4. Start the vacuum pump and vacuum system of approximately -29.92 in. Hg.
5. Close the gauge manifold hand valves and stop the vacuum.
6. Disconnect the center hose of the gauge manifold from the vacuum pump and connect it to a cylinder containing (R-11) refrigerant.
7. Open the cylinder valve.
8. Loosen the center hose connection at the gauge manifold. Purge the hose for a few seconds; then tighten the connection.
9. Open the gauge manifold hand valves and charge the system with (R-11) Refrigerant up to 5 psig.
10. Close the refrigerant cylinder valve and gauge manifold hand valves.
11. Disconnect the hose from the cylinder and purge the pressure from the system by opening the gauge manifold hand valves.
12. Repeat procedures c through k for three times.
13. Repeat procedure c through e.
14. Disconnect the center hose of the gauge manifold from the vacuum pump and connect it to the cylinder of applicable refrigerant.
15. Repeat procedure g through h.
16. Open the gauge manifold hand valves and charge the system with applicable refrigerant up to the standing pressure of the cylinder tank.
17. Start the air conditioning unit and add the proper charge of refrigerant
18. This procedure shall be done at an ambient temperature of not less than 34°C.