Suburban SW6D Water Heater Won't Stay Lit: Quick DIY Troubleshooting Guide

Tools & Parts Needed

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Recognizing the Signs

If you're experiencing this issue, you're not alone. Here's what's typically happening and how to address it.

What You Might Notice

Your Suburban water heater won't stay lit with the door closed because it's not getting adequate combustion air or the ECO (Energy Cut Off) switch is malfunctioning.

The Underlying Issue

The most frequent cause is blocked combustion air intake. Suburban water heaters require specific airflow patterns for safe operation. When you open the door, you're providing additional combustion air that bypasses the blocked intake.

Spider webs and insects are particularly common culprits, as they're attracted to the warm, dark spaces around the burner assembly. ECO switch tripping can also cause this symptom, as the safety system detects improper combustion conditions.

Other causes include:

• Corroded or damaged burner tube
• Improper venting causing backdrafts
• Gas pressure irregularities
• Faulty gas control valve
• Damaged or misaligned flame sensor

What to Grab

• Compressed air or shop vacuum
• Soft brush or old toothbrush
• Screwdriver set
• Multimeter (optional)
• Flashlight or headlamp
• Safety glasses

The Repair Process

1. Turn off and cool down: Shut off the propane supply valve, turn off the water heater switch, and disconnect the RV battery or turn off the electrical breaker to the water heater. Wait at least 30 minutes for the unit to cool completely.
2. Remove the outer door: Take off the exterior access door to expose the water heater compartment and burner assembly.
3. Inspect combustion air intake: Look for the combustion air intake screen or louvers, usually located near the bottom of the unit. Check for spider webs, debris, lint, or other blockages.
4. Clean air intake passages: Use compressed air to blow out any debris from the combustion air intake. Work from inside the compartment outward to avoid pushing debris deeper.
5. Check the burner tube: Inspect the burner tube for rust, corrosion, or debris that could restrict airflow. Clean gently with a soft brush if needed.
6. Examine the ECO switch: Locate the ECO switch (usually a small reset button mounted on the rear of the tank). If it has tripped, identify and correct the underlying cause before pressing to reset. If the ECO switch trips repeatedly, discontinue use and contact a professional.
7. Inspect door seals: Check that the outer door seals properly when closed, but isn't so tight that it restricts necessary airflow.
8. Test operation: Reconnect propane and wait 5 minutes for any residual gas to dissipate. Check all connections for gas leaks using soapy water. Turn on the water heater and test with the door closed. Monitor for several complete cycles, checking that flames are blue and steady, the ECO switch doesn't trip, and each cycle completes normally.

Situations That Need a Professional

Contact a certified RV technician if:

• You smell gas during operation
• The problem persists after cleaning air intakes
• You're uncomfortable working with propane appliances
• The burner flame appears yellow or irregular
• You suspect gas pressure or control valve issues
• The ECO switch continues to trip after cleaning

Remember: Propane appliances involve potentially dangerous gases and combustion. When in doubt, professional service is worth the cost for safety.