An E1 or E2 code on your Della mini-split display signals a sensor problem inside your indoor unit. These temperature sensors help your system understand how warm or cool your space is. Without accurate readings, your unit can't operate properly.

The fix is often simpler than you'd expect. Many homeowners resolve this issue themselves by following a logical sequence of checks.

Understanding E1 and E2

Your indoor unit contains two key sensors. The room temperature sensor monitors the air in your living space. The coil temperature sensor tracks the evaporator coil's condition.

E1 typically points to a room sensor issue. E2 usually indicates a coil sensor problem. Both sensors connect to the indoor unit's control board, known as the PCB (printed circuit board). This board processes sensor data and controls system operation.

A disruption in this communication chain triggers the error code. The cause could be as minor as a loose wire or as significant as a failed component.

Before You Begin

Turn off the power to your Della mini-split at the breaker or disconnect switch. This step protects both you and the equipment during inspection.

Gather these items:

• A screwdriver for panel removal
• A flashlight
• A multimeter (for sensor testing)

The troubleshooting process moves from simple to complex. Start at Step 1 and stop as soon as the error clears.

Step 1: Inspect the Sensor Connection

A loose connection causes E1 and E2 errors more often than actual component failure. Vibration, settling, and normal wear can gradually loosen plugs over time. Checking this first saves you from unnecessary repairs.

Open your indoor unit's front panel. Locate the thin wires running from the sensors to the main control board. These wires terminate in small plastic connectors.

Look for these issues:

• A connector that's only partially inserted
• Misalignment between the plug and the socket
• Visible dust or corrosion on the contacts

If anything appears off, disconnect the plug completely. Clean away any debris, then reinsert it until you feel or hear it click into place. A secure connection should feel snug.

Close the panel and restore power. Give your unit a few minutes to initialize.

The E1 or E2 code should disappear if a poor connection was the cause. You can stop here and resume normal use.

If the error returns, the connection isn't the problem. Move to the next step.

Step 2: Test the Sensor

A secure connection rules out wiring issues. Now you need to determine whether the sensor itself has failed.

Temperature sensors work by changing their electrical resistance based on the surrounding temperature. A healthy sensor produces predictable readings. A damaged one gives erratic results or no reading at all.

Testing with a multimeter:

Set your multimeter to measure resistance (ohms). Disconnect the sensor from the PCB and touch the probes to the sensor's two terminals.

At room temperature—around 25°C (77°F)—a functioning sensor should read approximately 5 kΩ (5,000 ohms). This value serves as a reference point. Resistance naturally drops in warmer conditions and rises in cooler ones.

Interpreting your results:

A reading of zero or near-zero suggests a short circuit. No reading at all indicates an open circuit. Either result points to sensor failure.

A reading far outside the expected range also signals a problem. The sensor may still function intermittently, but replacement is the reliable solution.

A reading close to 5 kΩ at room temperature suggests the sensor is working properly. If the error persists despite a normal reading, the issue likely lies elsewhere.

Step 3: Act on Your Findings

Your test results determine the next move. Two scenarios typically emerge at this point.

The Sensor Is Faulty

Replacement is straightforward. Contact your manufacturer or search for your model's specific part number. Most sensors cost between $10-30 and are widely available online.

Installation tips:

• Match the replacement sensor to your exact unit model
• Route the new wire along the same path as the original
• Push the connector firmly into the PCB socket

Restore power after installation and monitor for the error code.

If E1 or E2 disappears, the faulty sensor was your problem. Troubleshooting is complete.

If the error remains despite a new sensor, proceed to the next scenario.

The Sensor Tests Normal (or Replacement Didn't Help)

You've confirmed the connection is secure. You've verified the sensor functions correctly—or installed a new one. Yet the error code persists.

This situation points to the indoor unit control board (PCB) itself. The board may have a defect preventing it from processing sensor data correctly.

PCB replacement falls outside typical DIY territory. The component costs $100-300, and installation requires careful handling of electronic connections.

Your options include:

• Contacting a certified HVAC technician for diagnosis and repair
• Reaching out to your manufacturer, especially if warranty coverage applies
• Attempting the repair yourself if you have electronics experience

Professional help makes sense here. A misdiagnosed PCB issue could lead to unnecessary expense, while improper installation creates new problems.

Knowing When to Stop

This troubleshooting sequence has built-in exit points. You don't need to complete every step if an earlier fix resolves the issue.

Stop troubleshooting if:

• The error disappears after reconnecting the sensor plug
• The error clears after sensor replacement
• A technician confirms the repair is successful

Continue troubleshooting if:

• The error code returns after each attempted fix
• You haven't yet worked through all possible causes

The goal is identifying and addressing the actual problem—nothing more. Once E1 or E2 clears from your display, your system should operate normally.

Quick Reference

The entire process follows a logical path:

1. Check the connection: Loose plugs account for many E1/E2 cases
2. Test the sensor: Measure resistance with a multimeter (5 kΩ at 25°C is the reference)
3. Replace what's broken: Start with the sensor; consider the PCB only as a last resort

Most homeowners can handle the first two steps with basic tools and patience. The third step depends on your comfort level and the specific component involved.

Final Thoughts

E1 and E2 errors follow a clear troubleshooting logic. Starting with the simplest possible cause—a loose connection—often yields results without spending money on parts or service calls.

Testing the sensor adds another layer of certainty. You'll know whether replacement makes sense before ordering anything.

Only after ruling out these possibilities should the PCB come into consideration. This approach keeps costs low and prevents unnecessary repairs.

Your Della mini-split communicates through error codes for a reason. E1 and E2 tell you exactly where to look. The rest is methodical problem-solving.

Read More: Understanding Mini Split Error Codes: A Quick Guide for Della Models