RV Water Heater Not Working: Complete Troubleshooting Guide
Your RV water heater not working is one of the most common failures RV owners face, especially after winter storage or extended trips. The good news: most water heater issues fall into a handful of predictable failure modes, and many are repairs you can do yourself. This guide walks you through the diagnostic sequence a licensed RV technician would use, organized by water heater type and failure mode.
Identify Your Water Heater Type First
Before troubleshooting, identify whether you have a tank water heater (Suburban or Atwood, typically 6 or 10 gallon) or a tankless unit (Furrion, Girard, or similar). The exterior access panel will have the brand name and model number. Tank heaters use a holding tank that recovers in 20 to 30 minutes. Tankless units heat on demand and use different diagnostic codes. The troubleshooting paths diverge significantly between the two.
Tank Water Heaters (Suburban, Atwood)
Propane Mode Won't Ignite
The most common failure on propane mode is a dirty or misaligned main burner. Pull the exterior cover and inspect the burner tube for spider webs, insect nests, or debris. Mud daubers in particular love the warm tube and will block ignition entirely. Clean the tube with compressed air. Next, check that the propane is actually flowing. Verify the tank valve is open, the regulator is functioning, and other propane appliances (stove, furnace) ignite normally. If only the water heater fails to ignite on propane, the issue is at the unit itself.
If propane is reaching the unit but it still will not ignite, inspect the electrode and the wire feeding it. The electrode should sit roughly 1/8 inch from the burner tube. If the gap is wrong, the spark will not jump correctly. Ceramic insulators on the electrode can crack and short to ground, which prevents spark generation. Replace the electrode if you see any cracking.
Electric Mode Won't Heat
If propane mode works but electric does not, the electric heating element is the most likely failure point. These elements eventually corrode from mineral buildup in the tank water. To test: with the water heater switched to electric mode and shore power connected, check for 120V AC at the element terminals using a multimeter. If voltage is present but the element is not heating, the element has failed and needs replacement. This is a common maintenance item, not a major repair.
If no voltage is reaching the element, check the circuit breaker in your RV's main panel, the inline fuse on the water heater wiring harness, and the thermostat that controls the electric element. A failed thermostat will prevent voltage from reaching the element even when the breaker is on.
Neither Mode Works
When both propane and electric modes fail simultaneously, the issue is usually in the shared control circuit rather than in the individual heating systems. Check the 12V DC power supply to the water heater circuit board. These units require 12V DC for the control logic even when heating with 120V AC. Low battery voltage (below 10.5V under load) can prevent the control board from functioning. Also check for a blown fuse on the 12V DC line to the water heater, typically located in the RV's DC fuse panel.
Tankless Water Heaters (Furrion, Girard)
Error Codes
Tankless units display error codes on the interior wall mounted control panel. The most common codes are: E1 (ignition failure, usually caused by low propane or air in the line after storage), E2 (flame detection failure, the unit ignites but cannot confirm the flame is sustained), E4 (overheating, typically from restricted water flow), and E5 (low water flow, check for kinked lines or a clogged inlet filter). Write down the error code before troubleshooting. It tells you exactly which system to investigate.
No Error Code, No Heat
If the wall panel is completely blank or unresponsive, check the 12V DC supply. Tankless units draw more power from the 12V system than tank heaters. Battery voltage below 11.5V can cause the control panel to shut down entirely. Also check the fuse on the 12V feed line. If the panel powers on but no error code appears and no heating occurs, try turning the unit off at the panel, waiting 30 seconds, and turning it back on. A firmware hang can sometimes prevent the ignition sequence from starting.
When to Call a Professional
Some water heater issues require professional service: any propane leak (smell of gas near the unit), a failed circuit board or control module (requires specific replacement parts and programming), anode rod replacement on aluminum tanks (Suburban units), and any repair that involves modifying gas lines or high voltage wiring. FixMyRV.ai can help you diagnose the issue and determine whether it is a DIY fix or a professional repair. Text us your specific situation and we will walk you through it step by step.
Get Instant Help With Your Water Heater
This guide covers the most common water heater issues, but every RV is different. If your specific situation is not covered here, text FixMyRV.ai with your RV year, make, model, and water heater brand. Our AI, backed by over 50,000 pages of professional repair manuals, will walk you through the exact diagnostic sequence for your unit.