air conditioning repair

8 Helpful Air Conditioner Troubleshooting Tips for Homeowners

You think hockey players are tough? Sure. But if you want the real definition of rugged, look no further than your air conditioner. You shut it down in the fall. It sits outside in the snow, cold, rain, and ice for six to eight months. Then when the first hot day arrives, you flick the switch on the thermostat and it’s game on! It starts immediately pumping out cool air on-demand, without missing a beat.

However, like any mechanical device, air conditioning units are prone to wear and tear as they age, or after sitting for long periods. That’s why it’s important to keep your eyes and ears open for any issues as you put your AC back in action.

To help, we’ve shared some of the more common concerns, along with troubleshooting tips for your central air conditioner.

1. I can’t get my AC to turn on

First, make sure the thermostat is set to ‘Cool’ and the temperature setpoint is at your desired indoor temperature. If you’ve done this, and the thermostat temperature is above your set point but the A/C condenser is not coming on, it may be another issue.

Next, check your electrical panel to ensure the breaker hasn’t been flipped to the ‘Off’ position over the winter.

If the electrical panel breaker for the A/C is in the on position, the next step is to check the AC disconnect to make sure that it is set to the ‘ON’ position. This is a grey box that is generally located beside the AC condenser outside your home. There will either be a plug that needs to be pulled out, rotated 180 degrees, and then reinserted – or a breaker style switch that needs to be in the ‘ON’ position.

If you’ve checked the AC disconnect and your air conditioner is still not turning on, it could be faulty wiring or an issue with the thermostat. Don’t worry. An AC repair specialist can quickly diagnose and repair the problem.

2. There’s a funny smell when I turn on my AC

There could be several causes for this. A musty or dusty odor may simply indicate your furnace filter needs to be replaced. This can also occur if your ductwork and vents haven’t been professionally cleaned for a while.

If you notice a smoky smell it could be faulty wiring, which requires immediate attention. Shut off power to your furnace and air conditioner and call a professional immediately. If you have reason to believe there is an actual fire (steady smoke or you see a flame), call the fire department.

3. My air conditioner keeps turning off and on repeatedly

This is a common problem known as “short cycling”. It may be due to a faulty or an incorrectly set up thermostat. It can be caused by a clogged filter. Short cycling can occur if the AC unit installed is oversized for the home. It may also be due to an improperly charged AC system.

If this happens to you, shut off the AC at the thermostat and have a professional diagnose the problem right away. It’s generally an inexpensive repair. But if you don’t get it fixed, short cycling can damage the compressor, which is costly to replace.

4. My air conditioner is running continuously

Your air conditioner is meant to turn on when the air is warm and shut off when the home reaches the desired temperature. If you notice the AC is constantly running and your home is not reaching your desired indoor temperature (especially on days when it is not extremely hot out) you have a problem. This is hard on the motor and your energy bill.

troubleshooting air conditioner

This can be due to a low refrigerant charge (possibly caused by a slow refrigerant leak in the system), a frozen AC evaporator coil (the coil which is inside your furnace), a faulty blower motor, or condenser fan motor, or dirty/plugged AC condenser coils. A clogged furnace air filter can also be the culprit

In the event, your unit is running, yet struggling to keep your home cool, check your furnace filter and replace if needed. Then check your outdoor condenser. If you notice that the condenser coils are dirty and clogged with debris, you can clean with your garden hose (see photo). If you have eliminated both of these potential causes and your home still struggles to stay cool, a visit from a qualified AC repair specialist will be required.

5. My AC is on but isn’t blowing cool air

The whole point of having AC is to cool off. Again, it may just be a blocked furnace filter or a plugged condenser coil. Check those first.

If your AC condenser is running but there is no airflow from the vents in your home, then you may have an issue with your furnace blower motor. This will require a technician to diagnose.

If your AC condenser outside is running and you have airflow from your vents (but that air is not cool) the condenser may require a top-up of refrigerant. This is a simple fix that can be done as part of an air conditioner tune-up visit.

6. My AC is making unusual noises (Shut it off immediately)

Do you hear a loud squeal or a grinding noise? Squeals are generally caused by a worn compressor, condenser coil blower motor, or possibly the blower motor in your furnace. If you notice a grinding sound, turn off your unit immediately and call a professional. This is often a sign of a failing compressor or failing bearings in blower motors. You will want to get the issue diagnosed and repaired ASAP before any further damage occurs.

7. My air conditioning unit is leaking water inside my home

You may notice water on the floor of your basement near your furnace or in proximity to the refrigerant line set running from your furnace to the AC condenser outside.

This can be caused by improperly insulated AC line sets. The insulation on the larger diameter line can deteriorate over time. When the larger diameter copper line set is exposed to air in the home, condensation will form, drip and then collect on floors (or in ceilings if the line set is running through a finished ceiling). Improperly installed line sets with exposed copper can cause this too.

Moisture leaking from your furnace is often caused by a blockage in the condensate drain lines, which run from the in-furnace evaporator coil to floor drains or condensate pumps. Sometimes a faulty condensate pump can overflow. In certain circumstances, water near your furnace is a sign that a frozen AC evaporator coil inside the furnace that is thawing. Whatever the reason, it is best to call a professional to get to the source of the issue.

8. There is frost around my condenser coil

While not common, ice can form around the condenser coil (located in the center of the main unit outside of your home). This usually indicates your AC is low on refrigerant and needs a refrigerant top-up. It may also be caused by dirt or debris in the condenser coils. In rare instances, it can be a problem with the condenser blower motor.

Preparing for your appointment

Once you notice an issue, it is always recommended that you turn off your AC system, and leave it off until the service professional takes a look.

In cases where the evaporator coil, line set, or condenser coil is frozen, the ice will need to thaw before a technician can properly diagnose the issue. Again, turn off your AC. This will help the evaporator thaw quicker.

Notice an issue? Call a qualified AC repair specialist

Air conditioning units are extremely sensitive, requiring specialized tools and training. They should only be repaired by qualified professionals. Many of the air conditioning problems we mentioned will become worse over time and can result in more costly repairs if neglected.

At the first sign of a problem, call an AC repair specialist. The quicker you get the issue fixed, the sooner you can go back to enjoying a cool home.

Offer Terms: Free Duct Cleaning with Install Financing


Finance your furnace or air conditioner installation with no interest or payments for 6 months, and get a free duct cleaning.

How to get the offer:

  1. Get a free online or in-home quote for A/C installation or Furnace installation from Advanpro.
  2. Apply for financing through Financeit via the Advanpro link: https://www.financeit.ca/s/y2HQMw
  3. Confirm and book your installation with Advanpro, including approved financing.
  4. Ask us to claim and book your free duct cleaning.


Free duct cleaning offer applies to new furnace or air conditioning installations that meet all of the following terms:

  • installation of Lennox furnaces or air conditioners
  • supply and installation fully-financed through a Financeit payment plan with no payments and no interest for 6 months (“6 month deferral”).
  • financing approved and installation booked between March 7, 2022 and June 10, 2022

Duct Work Sanitizing

If you or your loved ones suffer from respiratory issues or allergies, or you’re concerned about the quality of the air that you are breathing, ductwork sanitizing treatments give you the reassurance that your ductwork is sterile and free of contaminants that negatively impact your respiratory and overall health.

Microban is a hospital-grade sanitizing solution, which kills 99.99% of germs, viruses, funguses, molds, and other pathogens.

We also offer Benefect, an all-natural sanitizer made from plant extracts, which also kills 99.99% of germs, viruses, funguses, and molds. ​

Dryer Vent Cleaning

Dryer fires are a top-five cause of house fires. Cleaning your dryer vent regularly greatly reduces the chance of a dryer fire, plus the following benefits:

  • Reduces clothes drying times
  • Lowers utility bills through greater efficiency
  • Extends the life span of your dryer
  • Lessens the amount of allergens in your house

Brush Cleaning Method

Our high-speed rotary brushing equipment sweeps the entire interior surface of your duct work, ensuring that all dust, debris, and pet hair are vacuumed away.

Physically cleaning the entire length of your duct work ensures that no contaminants are left behind, increasing your indoor air quality and peace of mind.

Reverse Octopus Whip Tool

The reverse octopus whip has eight 16” flexible tentacles, which whip around blasting high-pressure air in all directions as it moves through your duct work.

The tool agitates and dislodges the most hard-to-reach dust, debris, and contaminants, moving them toward our duct vacuum for collection and disposal.

Furnace Tune Up

Regular furnace tune ups are essential to maximizing the lifespan and efficiency of your furnace, so you can rely on it to keep you warm all Winter long.​

During our 30+ point inspection, we check all furnace systems to identify components that are worn out and need replacement. Replacing parts before they break — preventative maintenance — maximizes heating efficiency, avoids no-heat emergencies, and saves on costly service calls. 

Home furnaces can last for 20 years or more if well-maintained. A professional furnace tune up every two years helps to preserve your investment for decades.

A/C + High-efficiency Bypass

The secondary heat exchanger in a high-efficiency furnace or A/C coil has delicate, closely spaced fins that must be protected during your furnace and duct cleaning.

For furnaces that require a bypass, we temporarily install a filter above the heat exchanger or A/C coil, and position our duct vacuum above the filter.

This bypass procedure prevents damage by ensuring all dust and debris in your supply duct work is collected before reaching the heat exchanger or A/C coil.

Standard furnaces without A/C don’t have secondary heat exchangers or A/C coils and don’t require the bypass procedure.

Exhaust Flu Stack Cleaning

Mid-efficiency furnaces produce a sand-like, mildly-corrosive byproduct. This substance condenses in the exhaust flu stack and collects over time near the inducer/venter motor, restricting exhaust gas flow. Eventually, it enters the inducer motor and causes premature wear on the furnace.

Exhaust flu stack cleaning removes the build-up to reduce the chance of motor failure and maximize the life span of your furnace. Preventative maintenance ensures your furnace runs efficiently all Winter long — without costly no-heat emergencies. 

HRV Cleaning

In Calgary, all homes built in 2016 or later have a Heat Recovery Ventilator (HRV). Some homes built or renovated after 2013 may also have an HRV.

An HRV efficiently replaces stale indoor air with fresh outdoor air, all year round.

As with any other air-handling equipment in your home, your HRV should be cleaned regularly to ensure the best possible indoor air quality.

Not sure if you have an HRV? Call our team to find out how you can tell.

Furnace Tune Up Checklist


Test & Check

Supply & Service

Measure & Record

A/C Tune Up

Regular preventative maintenance improves efficiency and extends the lifespan of your air conditioning system, with the following benefits:

  • Reduced electricity bills and operating costs. When the unit operates as designed, electricity usage is reduced.
  • Maximized cooling capacity. Home comfort on the hottest of days with minimum run time.
  • Minimized repair bills. Detect and fix small problems before they get worse.

Hot water tank types

Natural draft or atmospheric vented hot water tanks have a 3″ – 4″ steel vent pipe, which runs to a vertical chimney. The chimney is usually shared with standard or mid-efficiency furnaces.

Power vented hot water tanks have one or two black or white plastic vent pipe(s), which are 2″ – 3″ in diameter. The vent pipes usually exit from the side of the house.

Correct furnace sizing guarantee

If the furnace Advanpro installs is determined to be undersized for your home, we will supply and install the correctly-sized furnace at no additional cost.

Advanpro must be immediately notified of any install issues. The guarantee applies for 3 months, starting from the installation date. The guarantee no longer applies if, at any time after the quote or installation, modifications are made to the home that impact heating requirements.

Correct A/C sizing guarantee

If the air conditioner Advanpro installs is determined to be improperly sized for your home, we will supply and install the correctly-sized A/C condenser at no additional cost.

Advanpro must be immediately notified of any install issues. The guarantee applies for 3 months, starting from the installation date. The guarantee no longer applies if, at any time after the quote or installation, modifications are made to the home that impact cooling requirements.

Repair guarantee

If the diagnosed issue is not fixed by our initial repair, we will dispatch the first available service technician to return and fix it at no additional cost.

If we determine that there is an additional unrelated issue, there may be a charge for the additional repair.

Quote guarantee


When we receive an online furnace or air conditioning quote request and the customer accepts the initial quote, we’ll send a comfort advisor to confirm the provided information and quoted price in person.

If the comfort advisor finds any inaccuracies during the in person visit, we’ll revise the quoted price on the spot. After the quoted price is confirmed with an in person visit, the price is set.

If there are unforeseen complications on the date of install, Advanpro will not pass the additional costs along to the customer. (See exceptions in Terms below.)


The guarantee is not valid if the customer provides inaccurate information when Advanpro seeks to confirm any information about the quote. This also applies to the on-site confirmation visit.

In the exceptional circumstance that the chimney liner required for most furnace installations cannot be installed or gets stuck during installation, the guarantee no longer applies and we will provide a supplementary quote to complete installation.

We do not warranty or guarantee customer-supplied thermostats.

Furnace & Duct Cleaning Checklist




Back Skipper Tool

The back skipper is a 1” diameter rounded ball connected to a long, flexible high-pressure airline.

The 1” ball has jets that discharge high-pressure air, pulling the tool and airline through the length of your duct work.

The high-pressure air moves the dust and debris toward our duct vacuum, where it is collected for disposal.​