Air conditioning repair and servicing

The phrase we hear most is "it is not cooling like it used to". That is a symptom with a short list of causes, and the order they come in is worth knowing before anyone quotes you for a new unit.

The two checks below cost nothing and resolve a large share of what we are called out to in August.

What should you check before calling anyone?

The filters and the outdoor coil, in that order. They are the two commonest causes of lost performance and they are both yours to look at.

Filters slide out of the indoor unit and are cleaned with water. Under heavy summer use they clog within weeks, and a clogged filter chokes airflow so effectively that the unit can run continuously and still not cool the room. If your unit has gradually got worse across one season, filters are the first suspect and very often the only one.

The outdoor coil is the finned block on the condenser. If it is packed with dust, seed or salt film, the unit cannot reject heat and its performance collapses in exactly the weather when you need it. Rinse it with fresh water at low pressure. Do not use a pressure washer: it bends the fins, and bent fins block airflow just as effectively as dirt.

If both are clean and it still underperforms, the cause is likely to be refrigerant, the condensate system or an electrical component, and those need instruments.

Why topping up the gas is not a repair

A sealed refrigerant circuit does not consume refrigerant. If a unit is low on gas, it has a leak — there is no other mechanism. Charging it without finding the leak sells you the same gas again next season, and usually sooner.

This matters more than it sounds, because the gradual version is easy to mistake for normal ageing. A slow leak produces a unit that cools a bit less each year, and it gets topped up each year, and nobody looks for the hole.

Finding the leak is the work. It is usually at a flare connection, at the service valves, or where the coil joins the pipework — and on this coast, corrosion at the copper-to-aluminium joint on an exposed condenser is a common culprit. Once found, it is a repair rather than a replacement.

Water coming from the indoor unit

This is a blocked condensate drain almost every time, and it is one of the more damaging faults to ignore because the water finds a ceiling.

The unit produces condensate whenever it runs, and that water leaves through a drain line. The line blocks with dust and biological growth over a season or two, the tray overflows, and the water goes wherever gravity takes it. It is not a refrigerant fault and it does not mean the unit is failing.

It is also entirely preventable. Clearing the drain is part of an annual service, and it is the single item most often skipped by whoever fitted the unit and never came back.

When is repair the wrong answer?

Three situations where we will say so rather than take the work.

A compressor failure on an old unit. The compressor is the most expensive component, and on a unit past ten years the cost of replacing it approaches a new system that will be substantially more efficient. We will price both and let you decide with the numbers in front of you.

A unit using an obsolete refrigerant, where a repair means sourcing gas that is being phased down and will get harder and more expensive to obtain.

A unit that was the wrong size for the room from the start. No repair fixes a specification error: an oversized unit will keep short-cycling and leaving the room clammy however well it is serviced. That is worth knowing before spending anything on it.

What does a service actually include?

Filters and the indoor unit cleaned, the outdoor coil cleaned, the condensate tray and drain line cleared, electrical connections checked and tightened, and the operating pressures and temperatures measured to confirm the charge is correct and there is no developing leak.

The right time is before the season rather than during it. An hour in May finds the connection that is running warm and the drain that is half-blocked while they are still a scheduled job, instead of a call-out in the middle of August at an August rate.

For a property that is let, servicing between changeovers is worth building into the calendar. Guests report a filter problem as a fault, and it is the commonest complaint that costs an owner a call-out fee for nothing.