Air Conditioner Repair

What usually goes wrong with central air

A central air conditioner is a simple loop: the outdoor unit compresses refrigerant and sheds heat, the indoor coil above the furnace absorbs heat from the house air, and the furnace blower moves that air through the ducts. When it stops cooling, the cause is usually in one of a handful of places, and many AC repairs in Hamilton are quick, inexpensive fixes made on the first visit.

• Capacitor: the most common failure. The outdoor unit hums but the fan or compressor will not start. Heat waves finish off weak capacitors.
• Contactor: the switch in the outdoor unit that turns it on. Pitted contacts or insects stop it closing.
• Dirty condenser coil: cottonwood fluff, grass clippings and dust choke the outdoor coil, and the unit loses capacity on hot days.
• Low refrigerant: there is a leak somewhere. The indoor coil can freeze and air from the vents turns lukewarm.
• Frozen indoor coil: a clogged filter, a slow blower or low refrigerant. Ice on the copper line outside is a sign.
• Blocked condensate drain: water around the furnace, or a safety float switch that shuts the AC off.

Before you call

Check that the thermostat is set to cool and a few degrees below the room temperature. Make sure the furnace blower is running, because the AC needs it. Check the furnace filter and both breakers: the outdoor unit usually has its own breaker and a disconnect switch on the wall beside it. If the indoor coil is iced up, switch the AC off and run the fan alone for a few hours to thaw it before the technician arrives; running it frozen can damage the compressor.

Refrigerant rules and old R-22 systems

Handling refrigerant in Ontario requires certification, and topping up a leaking system without fixing the leak is not good practice. Most air conditioners installed before about 2010 use R-22, which can no longer be manufactured or imported in Canada. What is left is recycled and expensive, so recharging an older R-22 unit can cost more than the system is worth. Units from roughly 2010 to 2024 use R-410A, and new equipment is moving to lower-impact refrigerants such as R-454B and R-32. Those refrigerants are not interchangeable, which matters when you are deciding whether to repair or replace.

Repair or replace?

Central air conditioners in southern Ontario usually last 12 to 18 years. If yours is past 12, uses R-22, needs a compressor or a major leak repair, or has been topped up every summer, replacement usually makes more financial sense. That is also the moment to ask whether a heat pump should replace it: a heat pump cools exactly like an air conditioner and also heats much of the year. The AC cost guide and new air conditioner installation page cover the numbers.

Who is allowed to repair an air conditioner

Air conditioning and refrigeration in Ontario is a licensed trade. Technicians work under a 313A (refrigeration and air conditioning) or 313D (residential air conditioning) certificate or as registered apprentices, and anyone handling refrigerant needs ozone depletion prevention training. Electrical work on the disconnect and wiring falls under the Electrical Safety Authority. Contractors we refer to carry the licences the work needs.

What the visit looks like

1. The technician checks the thermostat, the filter and the indoor blower, then the outdoor unit.
2. They test the capacitor, contactor and fan motor, and listen to the compressor start.
3. They measure refrigerant pressures and temperatures to see whether the charge is right.
4. If refrigerant is low, they look for the leak with an electronic detector or bubble solution.
5. They quote the repair before doing it, and say how much life the system likely has left.

Heat waves and health

Hamilton summers regularly bring humid stretches above 30 °C, and the city issues heat warnings when it gets dangerous. If someone in the house is elderly, very young, pregnant or has a heart or lung condition, say so on the request. In the meantime, close blinds on sunny windows, run fans, stay on the lowest floor and use a city cooling centre if needed.

How the request works

You request an AC repair once, and we pass it to one licensed contractor who works your area, from Stoney Creek to Milton. They call to confirm the symptoms and book a visit. Mention the age and brand of the outdoor unit if you can see the label: it helps them bring the right parts.