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How to troubleshoot a wall-mounted air conditioner?

Troubleshooting Wall-Mounted Air Conditioners: Expert HVAC Guide by AirGreen Montreal

AirGreen, Montreal's foremost HVAC service provider, understands the critical role that wall-mounted air conditioners play in ensuring a comfortable and healthy living environment. On occasion, your air conditioning unit may not function as expected. This blog post explores some common issues and their potential fixes, providing you with a guide to troubleshooting a wall-mounted air conditioner.

No Cool Air

If your wall-mounted air conditioner isn't providing cool air, it might be due to low refrigerant levels. In many cases, this issue is caused by leaks in the refrigerant lines. Such leaks should be repaired by HVAC professionals, as refrigerant requires careful handling. Contact your HVAC service provider if you suspect a refrigerant issue.

Insufficient Cooling

Insufficient cooling could be due to a multitude of issues. Firstly, check your air conditioner's filters. Dirty or clogged filters restrict air flow, reducing the unit's cooling capability. Cleaning or replacing your filters might resolve this issue.

Next, examine the condenser unit located outside your house. Ensure it's clean and clear of any debris or blockages that might restrict air flow.

Finally, consider the size of your room. A wall-mounted air conditioner might struggle to cool a room if it's too large for the unit's cooling capacity.

Air Conditioner Not Turning On

If your air conditioner doesn't turn on, it might be an electrical issue. Ensure the unit is properly connected to a power supply. Check the circuit breaker and reset it if necessary.

If these steps do not solve the problem, there could be an internal electrical issue. Contact a professional HVAC service provider to inspect and repair the unit.

Noise and Vibration

Noise and vibration are typically caused by loose or unbalanced parts. Inspect the unit for loose screws and tighten them if necessary. Ensure the unit is properly mounted and secure on the wall. If the noise continues, it might be an internal issue that requires professional assistance.

Water Leaking

Water leaking from the indoor unit is usually due to a blocked condensate drain. Over time, the drain can become clogged with dirt and debris, causing water to back up and leak from the unit. You can try to clear the blockage yourself, but if this doesn't work, it's best to call in an HVAC professional.


While some troubleshooting can be done by the homeowner, complex problems should always be addressed by trained HVAC professionals to avoid damaging the unit or voiding the warranty. AirGreen, a trusted HVAC service provider in Montreal, is always available to assist with your wall-mounted air conditioner problems.

We should note that a wall-mounted air conditioner does not provide heat like a wall-mounted heat pump does. It's function is to cool your spaces during the warm Montreal summers, so maintaining its optimal functioning is essential.

Turn to AirGreen for your HVAC needs and enjoy a cooler, more comfortable home.