Air Conditioning Maintenance

Learn how to take care of your air conditioner and ensure it's operating properly.

The basics

Keeping your air conditioner running well is essential for peace of mind — and to protect you from unexpected costs. It’s easy to do and all here in this guide.

Whole-home air conditioners are typically very reliable, but they still require the following regular maintenance:

Change the furnace filter regularly — Follow the instructions in our furnace maintenance guide. Air conditioners have delicate heat exchangers that are easily blocked and damaged by dust and debris, so you should always have a furnace filter installed.

Keep the outdoor unit, vents, and returns clear — Air conditioners rely on unobstructed air flow, inside and out. Regularly check your indoor vents and the outdoor A/C unit for blockages. Never use your fingers or other tools to clean the outdoor A/C unit; only water from a garden hose.

Watch out for A/C problems — In the Spring, follow our A/C startup checklist. Problems often appear within the first few weeks of use after startup. Unusual behaviour, sounds, smells, and water leaks are signs of A/C problems that may require professional repair. 

Finally, all A/C units and furnaces need a professional touch, including regular tune ups every one or two years.

Refer to the furnace glossary if you need help identifying furnace parts or terms.

A/C startup checklist

When the weather is getting warmer and you want to start using your air conditioner, follow this checklist to get it ready.

Start by preparing the outdoor A/C unit (also known as the condenser):

  1. Clear the area around the A/C unit.
  2. Remove the Winter cover from the A/C unit, if you have one.
  3. Use a garden hose to gently rinse the A/C unit from all directions.
  4. In the outdoor electrical disconnect box, set the switch to ‘ON’.

Next, move inside to the furnace room and electrical panel:

  1. Make sure a clean furnace filter is installed.
  2. In the electrical panel, set the breaker(s) for your air conditioner to ‘ON’.

Then, get the rest of your home ready: 

  1. Open all air supply vents.
  2. Ensure all return vents are clear of obstructions.
  3. Close all windows.

Finally, turn on the air conditioner:

  1. Set the thermostat mode to ‘Cool’ or ‘Auto’
  2. Set the thermostat below the current indoor temperature.

Within a few minutes, you should hear the A/C turn on and feel cool air from the vents.

Always be on the lookout for common air conditioner problems.

Common A/C problems

Some of the following common air conditioner issues have do-it-yourself solutions, but most require professional attention. Don’t hesitate to call us for A/C repairs.

This can happen if your thermostat is not set correctly, needs new batteries, or if one of the air conditioner breakers is disconnected. Try the A/C startup checklist first, then contact us to book a repair.

This can be caused by a blocked furnace filter or A/C condenser coil, frozen A/C evaporator coil, low refrigerant, faulty furnace blower motor, or faulty A/C condenser fan motor. 

When the air conditioner is running continuously and not keeping up with your cooling requirements, it’s hard on your A/C unit, furnace blower motor, and energy bills.

If you’ve tried the A/C startup checklist and the problem remains, stop using your air conditioner and contact us to book a professional diagnostic.

This can be caused a blocked furnace filter, thermostat problem, oversized A/C unit, or improper refrigerant charging.

Repeated A/C startup and shutdown is also called “short cycling.” Short cycling can damage the compressor, which is expensive to replace. 

If you’ve tried the A/C startup checklist and your air conditioner continues to short-cycle, stop using it and contact us to book a professional diagnostic.

Frost or ice formation on the condenser coil (located in the centre of the outdoor A/C unit) can be caused by low refrigerant, blocked condenser coils, or a faulty condenser fan motor.

Similarly, frost or ice formation on the evaporator coil (attached to your furnace) can be caused by a blocked furnace filter or faulty furnace blower motor. Frost or ice can also form on poorly-insulated or exposed A/C lines. 

If you’ve tried the A/C startup checklist and you continue to see frost or ice build up, stop using it and contact us to book a professional diagnostic.

A loud squeal or a grinding noise is a sign of a worn or failing A/C compressor, condenser fan motor, or furnace blower motor.

If notice sounds like this, stop using your air conditioner and contact us to book a professional diagnostic.

A musty or dusty odour while your air conditioner is running can be caused by a dirty furnace filter or ductwork overdue for cleaning. If you’ve replaced the furnace filter and the smell remains, contact us to book a furnace and duct cleaning.

If it smells like smoke or burning plastic while your air conditioner is running, stop using it immediately and shut off power to the A/C and furnace. This can be caused by faulty wiring or failed parts and is a fire risk. If you see smoke or flame, call the fire department. Don’t use your air conditioner until you’ve had the problem professionally diagnosed

Water leaks can be caused by a poorly-insulated or exposed A/C line set, blocked condensate drain line, faulty condensate pump, or a frozen/thawing evaporator coil.

It’s normal for water to flow from the evaporator coil attached to your furnace through the attached line to the drain or condensate pump (if you have one). Water should not be pooling or leaking anywhere else.

Leaks of other fluids are never normal and can be caused by a broken refrigerant line.

If your air conditioner is causing water to build up anywhere in your home, or has a fluid leak of any kind, stop using it and contact us to book a professional diagnostic.

Professional service

Even the cleanest homes build up dust and debris in the furnace ductwork over time. Get a furnace and duct cleaning every year or two to keep your indoor air as clean as possible. 

Annual air conditioning tune ups will keep your A/C operating at maximum efficiency and identify problems — before they become failures or major repairs. Our A/C maintenance plans include an annual tune up, furnace filters, and priority service.

Finally, be prepared for the unexpected. If you ever need air conditioner repairs, call Advanpro to get your A/C back up and running as soon as possible.

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Air conditioner repairs should only be performed by a certified technician.

This website is for informational purposes only. Advanpro Ltd. is not liable for property damage, personal injury, or death caused directly or indirectly by actions taken as a result of the information provided here.