HVAC Error Code L8 — Compressor Current Overload Fix

What Does This Error Mean?

HVAC error L8 means the compressor is drawing more electrical current than it should. The system detects this and shuts down to prevent the compressor from burning out. Think of it like a circuit breaker specifically protecting the compressor. Overheating, low refrigerant, a failing capacitor, or a dying compressor are the usual causes. Do not keep trying to restart the system — let it cool down and address the cause first.

Affected Models

Mini-split air conditioners
Central air conditioners
Heat pumps
Window AC units (larger commercial models)

Common Causes

Compressor is overheating due to a dirty condenser coil blocking heat dissipation
Low refrigerant charge is causing the compressor to work harder than designed
Start or run capacitor is failing, causing the compressor to draw excessive current during startup
The compressor itself is mechanically worn and requires more current to do the same work
High ambient temperature outside is causing the refrigerant system to operate at higher pressures, loading the compressor

How to Fix It

Turn the system off immediately and do not attempt to restart it right away. Allow the compressor to cool for at least 30 minutes before doing anything else.

Repeated restart attempts on an overloaded compressor cause rapid temperature buildup that can permanently damage the compressor windings.
Inspect and clean the outdoor condenser coil. Turn off power to the outdoor unit at the breaker first. Gently spray the condenser fins with a garden hose from the inside out (not a pressure washer). Remove any leaves, grass, or debris from the coil surface.

A dirty condenser coil traps heat and forces the refrigerant to reach higher pressures, which directly increases compressor current draw. Regular cleaning prevents L8 errors.
Check that the outdoor unit has adequate clearance. There should be at least 2 feet of open space on all sides and overhead. Overgrown bushes, fences too close to the unit, or debris against the coil restrict airflow and cause overheating.

Shade is beneficial — shading the outdoor unit can reduce compressor work by up to 10%. However, do not block airflow in the process.
Have the start/run capacitor tested. This is a component that helps the compressor motor start and run efficiently. A weak capacitor causes the compressor to draw excessive current. A technician can test it with a capacitance meter. Capacitors cost $10-$50 to replace.

Capacitor failure is one of the most common and inexpensive causes of L8. It is worth checking this before assuming the compressor itself needs replacement.
Have a technician check refrigerant levels. Low refrigerant causes the compressor to over-work trying to build the pressure needed to cool your space. Adding refrigerant (if there is a leak, also fixing the leak) is typically a $200-$500 repair.

Refrigerant handling requires EPA 608 certification. Never attempt to add refrigerant without proper training and equipment.

When to Call a Professional

L8 compressor overload errors should be evaluated by a licensed HVAC technician. Refrigerant levels and compressor health checks require specialized tools and EPA certification. Ignoring this error and repeatedly restarting the system can cause permanent compressor failure, which is the most expensive HVAC repair — often $1,500 to $3,000 or more.

Frequently Asked Questions

If I clean the coil and it works again, do I need a technician?

If the system runs without showing L8 again after cleaning and a brief test run, you may be fine for now. However, the L8 error indicates the system was under significant stress. Having a technician check refrigerant levels and do a seasonal tune-up is still recommended. If L8 comes back within days or weeks despite a clean coil, a deeper cause (refrigerant, capacitor, or compressor) needs professional diagnosis.

Is it normal for L8 to appear on very hot days?

Somewhat. On days with extreme heat (above 100°F / 38°C), outdoor units work harder than normal and may occasionally trip protective shutdowns. However, modern systems are designed with these conditions in mind and should not regularly trip overload protection even in high heat. If L8 only occurs when it is unusually hot and the coil is clean, it likely indicates the system is undersized for your space, or refrigerant levels are slightly low.

What does the compressor actually do?

The compressor is the heart of your air conditioning system. It is a pump that circulates refrigerant by compressing it from a low-pressure gas into a high-pressure hot gas. This hot gas then flows through the outdoor coil where it releases heat to the outside air. After cooling, it expands back into a cold liquid that absorbs heat from inside your home. Because it is under constant mechanical load, the compressor is also the most expensive component in an HVAC system.