AC Won’t Turn On: Troubleshooting Steps
During the late spring and early summer you depend on flipping your air conditioner switch for a comfortable home. If you’ve tried multiple times but your air conditioning unit is still not turning on, it’s time to troubleshoot the problem. Learn with Lew Plumbing & Heating as we explain the reasons why your air conditioning system might not turn on.
How Your Air Conditioner Works
Modern air conditioners typically feature three main components: the compressor, the evaporator, and the condenser. A problem with these three components may prevent the system from turning on. Below is a summary of how an air conditioner works to help provide greater insight into potential issues with your system.
The cooling begins when the thermostat senses the air temperature should be lowered and signals to the unit controls to start the cooling process. When you turn on the air conditioner, fluid enters the compressor as a gas at low pressure while the fan from the indoor unit pulls hot air from inside the home through the return air ducts. The refrigerant gas leaves through a copper tube and goes into the compressor in the AC unit outside. The compressor compacts the fluid, so the molecules become tightly packed together. Molecules forced together generate higher heat and energy levels. After being forced together, the fluid molecules exit the compressor as a high-pressure gas and travel to the condenser coil, where heat quickly dissipates.
The high-pressure levels change the gas to a liquid. The liquid cools as it enters the evaporator before it travels back inside the home through the copper tube. It then enters an expansion device to regulate refrigerant flow to the evaporator. Within the evaporator, the pressure drops, and the fluid turns into a gas, repeating the air conditioning cycle. This process allows heat to be extracted from the surrounding air while the metal fans of the evaporator exchange thermal energy with the air around the unit. This comprehensive air conditioner guide from the government of Canada can help answer all of your questions regarding AC equipment performance.
Potential Reasons Why Your Air Conditioner Won’t Turn On
Faulty Thermostat
The thermostat is a piece of equipment that monitors and cools indoor temperature. A faulty thermostat may be due to an overheating AC system or debris such as dust or moisture within the thermostat. The fault could also relate to the wiring of the thermostat. If you’ve tried resetting the unit and replacing the batteries, any additional and more complex work is best left to the specialists.
Signs of a Faulty Thermostat:
- The temperature on the display does not match your indoor temperature.
- Irregular cycling as the thermostat continually attempts to cool the home.
- The display fails to turn on after changing the batteries.
A Drainage Problem
AC drainage issues occur when the drain pan fills and overflows, sending water back into the unit. You may also experience an AC drainage issue if the drain line shifts due to ground settling or a bump, which sends moisture away from the pan and into internal systems components.
Signs of an Air Conditioner Drainage Problem:
- Musty, mold smell near the indoor unit or the vents and registers.
- Standing water near the indoor unit.
- Water damage on the floor and equipment near the air conditioner.
A Frozen Evaporator Coil
The evaporator coil is one of the critical components involved in air conditioning. A frozen evaporator coil occurs when the coil does not receive an adequate supply of refrigerant or air. A frozen coil often prevents the air conditioner from turning on and stops all airflow.
Signs of a Frozen Evaporator Coil:
- Ice on the outside refrigerant line.
- Condensation on the air handler.
- Increased condensation on windows around the home.
A Condenser Issue
Homeowners with window air conditioners often experience problems with their condenser coming unplugged during the day, which stops the unit from starting up and producing cold air. You may also notice a ticking or chattering noise if your AC system fails to turn on due to a condenser problem.
Signs of a Condenser Problem:
- Increased fluid leaking from the AC unit.
- Increased noise from the unit in the weeks before the AC failed to turn on.
- Loud humming noises from the condenser when you turn it on.
Lew Plumbing & Heating: Over 30 Years of AC Service Excellence
Backed by our decades of experience repairing air conditioning units for homeowners throughout Vancouver, Burnaby, Coquitlam, New Westminster, and the surrounding Lower Mainland, Lew Plumbing is your local air conditioning service specialist. We offer 24/7 access to AC service specialists throughout the summer. Request your home visit today, and we will dispatch your expert within minutes.
