What Can You Do If Your Cooling System Won’t Turn On?

Fix Broken AC

When your cooling system won’t turn on, many Hoosier homeowners are quick to worry about such a major problem. When the temperature outside is hot, a home without air conditioning, a functional heat pump, or mechanical cooling system can turn your space into a warm, uncomfortable mess. A number of components could be involved in such an issue, though professional repair isn’t always necessary to diagnose an air conditioning system that appears broken. Before you call for HVAC repair service, these troubleshooting tips can help you fix your cooling system unit and start it up again soon.

When your cooling system problems include an air conditioning that won’t start, check  these components to diagnose simple service issues first. Many times, there’s no need to repair or replace an air conditioning unit. All your system may need is a quick check and an easy fix, which doesn’t cost a cent!

What Would Cause an Air Conditioning Unit to Not Turn On?

A heat pump or air conditioning unit has many components, and malfunctions involving various parts can cause the system to not turn on and the temperature to warm up inside your house. While a number of problems will require professional repair, there are a few common issues that cause a cooling system not to turn on that troubleshooting can usually solve.  These cooling system problems include:

  • Power issues
  • Thermostat problems
  • Clogged filters
  • Clogged drain line

How Do I Fix My Air Conditioner That Won’t Turn On?

Before you call your HVAC professional to schedule repair services, we recommend you perform some quick troubleshooting steps to diagnose simple problems without the cost of a service appointment. If your heat pump or air conditioning unit cooling system will not start this summer, run through these steps first, as they may save you hours of uncomfortable waiting.

Troubleshoot Power Problems

The easiest explanation is commonly the answer – if your mechanical cooling system won’t turn on, does it have power? Your first step is to inspect all system power sources and each switch that controls your equipment.

  • If your thermostat runs off battery power, check the display for a low battery alert. If the display is blank and doesn’t turn on at all, you may have a battery issue – replace the batteries now. Often times, new batteries are all it takes to fix an unresponsive thermostat.
  • Inspect the home’s main electrical panel to see if a circuit breaker switch has tripped on any of the circuits running your cooling system equipment or thermostat (if hardwired to the home’s electrical system). If you find a tripped switch, reset it.
  • The indoor unit and outdoor heat pump or air conditioning unit each have an ON/OFF switch located on the unit or on a nearby wall. Make sure this switch is flipped to the ON position.

Thermostat Issues

An incorrectly set thermostat or a malfunctioning unit can cause an air conditioning system not to start when expected. The thermostat is the device that communicates with your cooling system or heat pump, alerting it when it is time to run a cooling cycle and when the cycle should end. If your air conditioning system doesn’t start up, check the thermostat settings after you inspect for electrical and power issues.

  • Make sure your thermostat is set to COOL. If the thermostat switch has been accidentally or incorrectly moved to HEAT, it will not trigger your air conditioning unit to run and cool the air – instead, the thermostat expects to signal your furnace for heat.
  • Check the temperature setting and make sure it is programmed a few degrees below the current room temperature, which should signal the air conditioning system to start a cooling cycle. This may be the problem if you expect your heat pump or air conditioner to turn on at a certain point yet it hasn’t.
  • If the settings are correct, your next step is to remove the thermostat faceplate. Debris buildup on internal sensors and loose wiring connections can cause an interruption in proper communication between the device and your cooling system. Carefully clean the insides of the unit with a can of compressed air and tighten any loose wiring terminals with a screwdriver before the faceplate is replaced. Make sure the faceplate is properly attached and the thermostat sits level.
  • If these steps do not fix thermostat-related cooling system problems, the device may need to be replaced. Your HVAC professional will be able to test the unit and the rest of the cooling system components to determine if this is the right repair solution.

Dirty Filters

If HVAC system filters become clogged with contaminants, filters can stop a furnace or air conditioning unit from turning on. A clogged filter prevents proper airflow through the system which can cause overheating. When components overheat and the internal temperature within the unit is too high, the system shuts down for safety, in order to prevent damage. Once electrical and battery power issues and thermostat settings have been cleared as the cause of your air conditioner not turning on, check filters.

  • Pull out the filter and remove it from the filter cabinet, which is usually located where the return duct meets the furnace or air handler unit inside your home.
  • Visually inspect the filter. Is the surface completely covered in grey matter? If there is no clean space left on the surface of the filter media, replace the filter.
  • If you have trouble determining if your filter could have some free space left, try holding it up to a light source. If you can see light through the filter when you check it, the filter is still usable.
  • After you check the filter, whether you need to replace it or reinstall the existing one, make sure you reinsert the filter properly when replacing it within the filter cabinet. Follow the arrow and number markings on the frame that show the correct direction for filter insertion.

Avoid serious cooling system issues this season when you check heating and cooling system filters regularly – once a month, at least. This is a critical maintenance step for heating and cooling equipment. Extremely clogged filters could cause serious damage to your air conditioning unit, warranting expensive service calls. Dirty filters prevent free air movement which not only could damage the system, but your home will not receive the cold air you expect due to this airflow restriction.

Clogs in the Drain Line

Air conditioning units and heat pumps produce condensation as they cool air during a cooling cycle. As the fan blows air across the evaporator coils, the coils cool the air and the moisture within condenses into water. It drops out of circulation, which provides some dehumidification.

Normally, the water will drip from the evaporator coils into a drain pan and flow out of the system through the attached condensate drain line. If the condensate drip pan or drain line is clogged, water backs up and fills the drip pan. Not only can water overflow and spill out of the system, which can cause water damage to the unit and the surrounding area, but the excess water volume can trigger a float switch which stops the system to prevent water damage.

Before you start placing calls for repair services, make sure you also check the air conditioning drain line.

  • Remove the panel to access the interior chamber of your air handler or furnace unit that holds the evaporator coils, so you can inspect the drip pan. If the pan is filled with water that is not draining, the line is likely clogged or could possibly be damaged.
  • To remove drain line clogs, shut off power to the cooling system at the nearby switch and electrical breaker.
  • Use a wet/dry vacuum to remove excess water from the drip pan. Hold the vacuum hose over the drip pan exit to suction out any clogs located where the drip pan and drain line connect or in the upper portion of the drain line. A plumber’s snake can also be threaded through the line to remove material clogging the drain.
  • Find the condensate drain line’s exit, which may empty into a nearby floor drain or outside your home. Make sure there are no obstructions at the exit opening. Attach the wet/dry vacuum to the exit to suction out clogs in the lower portion of the drain line, or use a plumber’s snake.
  • Check the PVC drain pipe for damage, as damaged portions of pipe can prevent water from draining away from the air conditioning indoor unit. If there is damage, the drain line needs to be replaced.

Performing these maintenance steps periodically throughout cooling season can help you avoid system issues and water damage.

Air Conditioning System Still Doesn’t Start?

If your air conditioning system still does not start up after you check the system drain components, power, filters, and thermostat, it’s time to call for professional repair services to solve the problem. A motor or fan problem may be to blame, electrical problems involving more complex components like the capacitor or contractor, or other mechanical parts may be broken or malfunctioning.

A broken cooling system happens to the best of us, heating up homes and leaving families to sweat through warm temperature discomforts. If your system doesn’t cool your home properly or won’t even start, call Williams Comfort Air for repair services. We perform thorough diagnostics to identify service issues and repair or replace problem parts. Call us today to schedule repair service for your air conditioning unit or heat pump.

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