DIY Fixes For Common Window Air Conditioning Unit Faults

Posted on: 12 November 2015

Window air conditioning units are a godsend during the hot summer months, but things can go wrong.  If you know how to fix the most common faults yourself, you'll not only have your air conditioning back up and running quickly, you'll save money on expensive contractor call-out fees too.

Here are some easy DIY fixes for some of the most common window air conditioning unit faults.

Fault – Iced-up condenser coils

This is a common problem with window air conditioning units.  The unit stops working properly and the condenser coils inside just freeze over.  The most likely reason for this is simply that the unit needs cleaning.

Switch off the unit.  Take off the plastic cover and remove the filter media inside the unit.  Have a good look at the fins of the structure behind the filter.  You'll probably find them blocked up with dust, fluff and other debris that is blocking the free flow of air through the unit.  As a result, warm air will not be able to flow over the refrigerant coils and they'll freeze over.

Take a trip to your local hardware store and buy a bottle of air conditioning unit coil cleaner.  Spray the coils liberally with the product then let it soak in.  When the cleaner begins to activate, it will bubble.  Rinse off the coils using clean water and clean out the drain pan thoroughly.  Switch the unit back on again – it should now be working properly again, and the coils will no longer freeze up.

Fault – water dripping from the front panel of the unit

If you notice water dripping from the front of the air conditioning unit, it is probably because the drain pan is sloping the wrong way.  Water condensate from the evaporator coil is therefore draining into your house, rather than out of the back of the unit via the drain tube.

Switch off the unit and reposition it correctly so that it slopes toward the exterior of the house.  This will allow the water to drain away correctly.

Fault – air conditioning unit cycles too frequently

This is usually a problem with the thermostat.

Sometimes, the thermostat can be compromised if the unit is obstructed by heavy curtains or blinds.  Make sure that there is unobstructed air flow around the unit.

If the airflow to the unit is clear, switch of the unit, remove the front cover, and check to see that the thermostatic sensor is correctly positioned near to the evaporator coil.  It should be close to the coil without actually touching it.  If necessary, adjust the positioning of the coil by adjusting the wire. 

If neither of the above fixes is applicable, the problem could be caused by an airflow issue within the unit itself.  Remove the filter media from inside the unit so that you can see the fins behind it.  Make sure that there are no dead leaves, fluff or other debris inside the unit that is obstructing the condenser.  If the unit is clogged with dust, vacuum it clean using the soft brush attachment on your vacuum cleaner hose.  If the fins are damaged or bent, repair them using a special fin comb that you can buy from a good hardware or DIY store.

In conclusion

There are simple fixes to common window air conditioning problems that you can carry out yourself.  If problems persist, always consult a professional air conditioning service engineer for further advice.