If you are seeing this code, you are likely experiencing a total loss of hot water, as the unit will enter a “lockout” state for safety. You might hear the internal fan spin up followed by a series of clicking sounds as the igniter attempts to spark, only for the unit to fail and flash the E248 code. While a gas-related error sounds intimidating, this guide will help you methodically diagnose whether the issue is a simple loose wire, a failing component, or a control board malfunction.
Symptoms of Navien Error E248
- Flashing Error Display: The front control panel or the wired remote will persistently flash “E248,” often accompanied by an audible beep.
- Lack of Ignition: You may hear the exhaust fan (blower) kick on, but you will not hear the “thump” of the gas valve opening or the roar of the flame.
- Ice-Cold Water: Because the gas valve is disabled, the heat exchanger cannot warm the water, resulting in no temperature rise at the tap.
- Cyclical Restarting: The unit may attempt to “self-correct” by restarting the ignition sequence several times before finally locking out with the error code.
- Clicking Noises: You might hear the solenoid on the gas valve clicking rapidly as it struggles to maintain an electrical connection.
Comprehensive Repair Guide
Comprehensive Repair Guide for E248
Follow these steps in order. WARNING: This repair involves working with electricity and combustible gas. If at any point you smell gas or feel uncomfortable, shut off the gas supply and call a licensed technician.
🛠️ Safety First: Read Before Repairing
Working with electricity is dangerous. We strongly recommend downloading the official guide.
- Perform a Hard Power Reset:
Before opening the unit, try a hard reset. Turn off the power button on the front panel, then unplug the unit from the wall outlet. Wait exactly 60 seconds to allow the capacitors on the PCB to discharge completely. Plug the unit back in and turn it on. If the error was caused by a temporary software glitch or a minor power surge, this may clear the E248 code. - Access the Internal Components:
Ensure the power is unplugged. Use your Phillips head screwdriver to remove the four screws securing the front metal cover. Carefully lift the cover off and set it aside. Locate the gas valve—it is usually the large component at the bottom center where the gas line enters the cabinet, connected by a thick wiring harness. - Inspect the Wiring Harness:
Visually inspect the wires leading from the gas valve to the Main PCB. Look for any signs of singeing, melted insulation, or pinched wires. Disconnect the plastic molex connector from the gas valve and inspect the pins for green/white corrosion. Use needle-nose pliers to ensure the pins are straight, then firmly reseat the connector. A “click” indicates a secure connection. - Test the Gas Valve Resistance (Multimeter Required):
Set your multimeter to the Ohms (Ω) setting. Disconnect the wiring harness from the gas valve. Place your probes on the terminals of the gas valve solenoids (refer to your specific model’s wiring diagram, usually found on the inside of the front cover).- Normal Range: Most Navien gas valve coils should read between 40 and 100 Ohms, though this varies by model.
- Infinite/Open: If your meter reads “OL,” the internal coil is burnt out, and the gas valve must be replaced.
- Check for Voltage from the PCB:
DANGER: High Voltage Risk. Plug the unit back in and call for hot water. Set your multimeter to DC Volts. Carefully back-probe the connector at the gas valve. When the unit attempts to ignite, you should see a momentary spike in voltage (typically 12VDC or 24VDC depending on the model). If the valve receives voltage but doesn’t click open, the valve is mechanically stuck. If no voltage is sent, the Main PCB is likely defective. - Verify Gas Supply Pressure:
While E248 is usually electrical, extreme low pressure can sometimes cause the valve to behave erratically. Ensure your external gas shut-off valve is fully open and that your gas regulator hasn’t tripped.
| Specification | Detail |
|---|---|
| Repair Difficulty | Intermediate to Advanced (Involves electrical testing) |
| Estimated Time | 45 – 90 Minutes |
| Tools Needed | Phillips #2 Screwdriver, Digital Multimeter, Needle-nose Pliers, Gas Leak Detector Solution |
| Estimated Cost | $0 (Reset/Wiring) to $250+ (Replacement Parts) |
Why is my Navien showing Error E248?
Understanding the root cause of E248 requires looking at the relationship between the Gas Valve and the Main PCB. Here are the most common reasons for this failure:
- Gas Valve Solenoid Failure: Inside the gas valve are electromagnetic solenoids. Over thousands of cycles, the internal copper windings can develop “shorts” or “opens” due to heat and wear. If the PCB detects that the solenoid is drawing too much or too little current, it triggers E248 to prevent a gas leak or fire hazard.
- Main PCB Fault: The Printed Circuit Board is the “brain.” If the relay or capacitor responsible for sending the 12V or 24V DC signal to the gas valve fails—often due to a power surge or simple component aging—the valve won’t receive the command to open.
- Wiring Harness Corrosion or Looseness: Navien units vibrate slightly during operation. Over time, the multi-pin connector that joins the gas valve to the wiring harness can wiggle loose. Additionally, in high-humidity environments, the metal pins can oxidize, creating electrical resistance that mimics a valve failure.
- Voltage Fluctuations: If your home experiences “dirty power” or frequent brownouts, the sensitive electronics in the Navien may misinterpret a dip in voltage as a gas valve malfunction, locking the system down as a precaution.
How to Prevent Error E248
To avoid a repeat of this error and extend the lifespan of your Navien water heater, implement the following maintenance strategies:
- Install a Dedicated Surge Protector: The PCB is highly sensitive to electrical noise. Using a high-quality surge protector designed for appliances can prevent voltage spikes from damaging the gas valve circuit.
- Annual Cleaning and Inspection: Dust and debris inside the cabinet can lead to overheating of the electrical components. Once a year, vacuum out the bottom of the cabinet and ensure all electrical connections are snug.
- Maintain Proper Venting: If the intake air is restricted, the unit may vibrate excessively as the blower works harder, which leads to loosened wiring harnesses and premature wear on the gas valve’s mechanical parts.
Frequently Asked Questions
Q: Can I manually clean the inside of the gas valve to fix E248?
A: No. The gas valve is a factory-sealed safety component. Attempting to disassemble the valve itself can lead to catastrophic gas leaks. If the internal solenoid or diaphragm has failed, the entire valve assembly must be replaced with an OEM Navien part.
Q: Is Error E248 covered under warranty?
A: Navien typically offers a 5-year warranty on parts and a 1-year warranty on labor (though this varies by model and installation date). If your unit is relatively new, contact Navien support with your serial number; they may provide the replacement gas valve or PCB at no cost.
Q: My unit works intermittently after I jiggled the wires. Is it fixed?
A: Likely not. If jiggling the wires temporarily clears the E248 code, you have a “loose connection” or a “cold solder joint.” While it works now, the vibration of the unit will eventually cause it to fail again—potentially at the coldest time of year. You should replace the wiring harness or the PCB to ensure a permanent fix.