Proper and scheduled air conditioning maintenance is essential in making sure that your air conditioning unit will be operational as long as possible. A properly maintained air conditioning unit will cost your less in the long run, and you don’t have to go around, looking for a new unit.
I would like to classify air conditioning maintenance into two categories,
This famous quote is so true, for maintaining any equipment. We’ll normally do more harm by “trying” to “fix” a problem that is not there in the first place.
The best bet is, to do some simple checks before undertaking maintenance activities.
Type 1: Air conditioning maintenance by yourself:
List of air conditioning maintenance at user level are,
Air conditioner filter maintenance,
External cleaning of condenser and evaporator,
Tube insulation care,
Condensate pan and drain care,
Simple damper maintenance,
Acidity test,
Moisture check,
Simple leak detection, and
Simple fan and blower diagnostic
Short details,
Air conditioner filter maintenance
Frequency of maintenance depends on the location of the conditioned room, and intake air condition.
Some would suggest a frequency of once a month, some would suggest once in three months.
The real fact is, there is no fixed frequency. We have to determine the frequency after two or three filter maintenance
Maintenance of the filter could be replacing the filter for disposable ones, or washing it for electrostatic filters
This problem is easily identified, and rectified using fin comb
External cleaning of the condenser and evaporator may be carried out without involving water or cleaning foam.
Combination of fin brush and a vacuum cleaner would do the trick quite nicely.
Use of cleaning foam and water would be the best, but it has to be carried out with the electrical supply isolated, and electrical equipment covered to prevent unnecessary water or cleaning solution ingress
Tube insulation care
This is probably the least problematic area within an air conditioning unit.
A good check would be, to find damaged parts of the insulation, and exposed parts of the vapour return line.
The remedy?
Get yourself a synthetic rubber tube insulation, matching with the vapour return line size,
Remove the damaged insulation (if any),
Cut required length of the insulation, and cover the exposed tube length,
Secure the insulation by wrapping the ends, with cable tie, or better still, with insulating tapes
Condensate pan and drain care
Condensate pan and drain care is probably the simplest air conditioning maintenance you can perform, but normally overlooked, creating unwanted moss formation, clogging, and evaporator unit flooding.
Maintenance that you can perform on monthly basis are,
Testing the water flow from the pan. Better still, use warm water, mixed with detergent
Cleaning any debris and dust from drain inlet to prevent clogging,
Cleaning of condensate pan with detergent and wiping it clean to prevent moss formation,
Use of wet and dry vacuum cleaner at the outlet of drain line, to pull out dead insects or remaining water within the line
Simple damper maintenance
A damper in air conditioning system may be operated manually, or automatically, using electrical motor, hydraulic system, or pneumatic system.
These dampers will have,
Linkages, and
Pivot
Cleaning of these points from dust and debris would prevent seizure of dampers.
Simple spray lubrication may be applied to these points, to prevent squeaking sound. Please make sure to wipe off the excess oil.
This maintenance may be carried out on quarterly intervals.
Acidity test
Is used to check for acidity in the refrigerant, or lubrication oil. This test is extremely important in making sure that the compressor will not fail prematurely, from parts erosion and corrosion.
Acid formation within the system happens due to excessive temperature rise, thus disintegrating the refrigerant into chlorine based, or fluorine based acid.
Normal causes for excessive temperature rise are insufficient lubrication, or insufficient cooling from the return refrigerant vapour.
The test could be performed by attaching a bulb to the vapour line service valve, and analysing the colour change of the litmus element.
Courtesy: Qwik
Such bulb is currently being produced by QwikTM, named QwikCheck.
According to QwikTM, if the result of the test shows red, then the system needs to be flushed from acid, refrigerant needs to be changed, filter dryer replaced, and lubrication oil needs to be replaced.
An orange indication means that the filter dryer needs a replacement, and the system needs to be flushed.
Moisture check
Moisture within an air conditioner system is equally as bad as acids.
Presence of moisture will cause ice formation at the low pressure side of the air conditioner, since the temperature will be lower than water’s freezing temperature.
Clogged refrigerant path will reduce flow of refrigerant, lubrication oil, and cause compressor overheating.
Air conditioners that are completely installed at site will have filter dryer, and sight glass attached. Hence presence of moisture within the system can be detected by formation of moisture at the sight glass.
However, there are air conditioners that are hermetically sealed at the manufacturer’s factory. These units will not have sight glass installed. Examples of hermetically sealed units are window air conditioners and portable air conditioners.
A way to check this is by checking if there is any leak within the system. If there is no leak, then there should be no problem.
Otherwise, repairs need to be carried out, and the system has to be re-sealed hermetically by the manufacturer, or a contractor.
Simple leak detection
Leak of air conditioner tubes will pose the threat of refrigerant loss and finally, no cooling or heating.
There are three famous simple leak detection methods at end user level. The,
Soap test
Electronic leak detector, and,
UV light test
Electronic leak detector is the most widely used method nowadays, with lightweight construction, and accurate pin-pointing of the leak position on the tube, or other air conditioner parts.
Treatment for leaks is either part replacement, or repair by tube soldering, or welding.
There is another air conditioning maintenance that is related to pump down, and evacuation.
This is system purging. Limitation of this maintenance activity lies within the construction of the air conditioning system.
Air conditioning system with a receiver or a service valve on top of the condenser will allow for system purging from non condensable gases (e.g. air).
This is performed by system pump down, followed by releasing the gases through the service valve on top of the condenser, or at the compressor’s discharge service valve (if available).
Alternatively, you can evacuate the system, leak test, and recharge with refrigerant.
Compressor lubrication oil maintenance,
consist of lubrication oil top up, and changing.
Changing of the lubrication oil is simple.
Evacuate the air conditioning system, take out the compressor,
Remove the old lubrication oil into a pan, fill with correct air conditioner compressor lubrication oil, and quantity
Reassemble the system, evacuate it, and charge with new refrigerant
Lubrication top up has a similar procedure to changing lubrication oil, but we don’t have to follow step (2).
Perform step (1). Top up until the correct level (based on compressor’s sight glass), and follow reassembling steps shown in (3).
System flushing,
is essential air conditioning maintenance in removing acid from the system.
by listening to low vibration hum, or clicking sound.
This indicates that there is either inadequate voltage to the contactor during engaged position, OR wear of the contactor's parts.
If changing the contactor doesn't solve the problem, then you have to modify the circuit to the contactor, such that there will be no voltage drop upon engaging
by observing on the operation of the compressor, blower, or fan.
Continuous running and inability to start might (and normally does) suggest a problem with a stuck contactor.
Try replacing the contactor and observe if it rectifies the problem
Motor capacitor checking
Air conditioner compressors and large blowers will normally be equipped with start capacitor and run capacitor.
Performing this air conditioning maintenance is easy. Check,
if the capacitors are oily, then replace without second thoughts,
if (according to Maintstream Engineering) the measured current, multiplied by 2,650, divided by the measured voltage, is lower than 10% of the design capacitance of the capacitor, then replacing it is the best thing to do.
Voltage measurement can be performed by a voltmeter.
Current measurement can be measured by an ampere probe
if you don't hear second "thud" a few seconds after the first "thud" sound during a compressor of blower start that utilises start capacitor,
then your start capacitor is most likely defective and needs to be replaced
General best practices on air conditioning maintenance:
It doesn’t matter, what type of air conditioning system we have, the responsibility of taking care of it lies on the owner, or the user.
The user has to take good care during installation, and proper air conditioning maintenance when in operation.
We have to install it as far as possible from sources of standing water, possible physical impact (e.g. adjacent to a football field), and we have to secure the unit firmly on the base/wall/window.
General care during normal operation includes keeping the unit as clean as possible, as dry as possible, and properly lubricated.
It is not advisable to operate the unit, if you’re occupying a space for less than 10 minutes (e.g. rushing back into the house to get your forgotten presentation material).
Finally, air conditioner maintenance or air conditioning maintenance should not be a complicated, and expensive, set of tasks.
In fact, these tasks will save you bucks in the long run. Get it right, and you’ll be enjoying comfort air for years to come.
Simply put, air conditioning maintenance is all about checking, and correct operation, before rectification.
