Why is my RV water heater clicking but not igniting?

Possible Causes

There are a few common reasons why an RV water heater might be clicking but failing to ignite:

1. No Propane Flow

One of the most likely culprits is a lack of propane flow to the water heater. There could be different causes for this:

The propane tank is empty – Refill the propane tank if needed.

The propane line is blocked – Inspect the rubber propane hose for kinks or damage. Make sure the hose is not pinched off.
Faulty propane regulator – The regulator controls propane flow from the tank to the appliances. If it’s damaged, replace it.
Shutoff valves closed – Make sure all propane shutoff valves at the tank, regulator, and water heater are fully open.

Without proper propane flow, the water heater will keep clicking as it tries to ignite but cannot. Tackle any propane flow issues first.

2. Igniter or Thermocouple Failure

Most RV water heaters use a thermocouple to sense the pilot light flame and keep the gas valve open. The igniter creates the spark to initially light the pilot. Issues with either can prevent ignition:

Faulty igniter – If the igniter is damaged or worn out, it won’t create a spark. Replace it.

Bad thermocouple – The thermocouple generates a small voltage to signal the gas valve to stay open when pilot is lit. If it’s defective, the pilot won’t stay on.

If you hear clicking but no spark at all, the igniter is likely bad. If there’s a spark but no ignition, the thermocouple probably needs replacement.

3. Air in the Gas Line

Sometimes air can get trapped in the propane line, which prevents the proper gas flow to the water heater. This is more common after running the propane tank out completely. Bleeding the air out of the lines can resolve this.

Here’s how:

Make sure propane tank valve is off.
Open hot water faucet inside RV.

Turn propane tank valve on very slowly, just barely cracked open.
Air should begin hissing out the water lines as propane pushes it through.
Once the hissing stops, open the propane valve fully.

Attempt to light water heater again.

This procedure forces air pockets out of the line so propane can get through. Always turn off appliances and faucets before purging air from propane lines.

4. Faulty Gas Valve

The gas valve is essentially the switch that allows propane to flow into the burner tube. If it’s not functioning properly, the water heater may keep clicking while failing to let gas enter to ignite.

Gas valve problems usually require replacement by a technician. You may be able to remove and clean the gas valve yourself if debris is blocking it, but take care not to damage any components.

5. Bad Control Board

Many modern RV water heaters have electronic control boards that operate the ignition sequence. If the control board is defective, that could explain the clicking with no ignition. Test the board and replace it if faulty.

6. Sediment or Mineral Buildup

Heavy lime and mineral deposits from hard water usage can accumulate inside the water heater over time. This can obstruct gas flow, prevent the pilot from staying lit, and cause other issues.

Flushing the water heater tank yearly can help prevent sediment buildup. Use a de-liming solution for more severe mineral deposits.

How to Troubleshoot the Problem

It takes some basic troubleshooting to figure out exactly why your RV water heater isn’t igniting. Here are some steps to diagnose the issue:

Make sure the propane tank isn’t empty – Confirm there’s adequate gas in the tank before continuing.

Check for propane flow – Turn a propane appliance on like the stove or furnace. If they don’t ignite either, there’s likely an issue with gas flow from the tank.
Inspect the thermocouple – Remove and visually check the thermocouple for damage. Replace it if the tip is overly corroded.
Check for spark – Activate the igniter and look to see if it sparks at the pilot. No spark indicates a bad igniter.

Inspect pilot tubing for blockages – Make sure all gas tubing and orifices are clear of debris like spider webs.
Clean flame sensor – Use steel wool to remove oxidation on the pilot flame sensor. This can prevent proper ignition.
Listen for solenoid valve clicks – Turn ignition on and listen for a clicking sound from the gas valve solenoid as it opens and closes.

Test components with a multimeter – Check thermocouple, igniter, and control board for proper ohm readings based on specs.

Following basic troubleshooting steps can help narrow down the issue. If needed, bring the water heater to an RV technician for further diagnosis and repair.

How to Fix the Problem

Once you’ve diagnosed the specific problem preventing water heater ignition, you can take steps to fix it:

Refurbish Thermocouple

If the thermocouple is producing low millivolts or is visibly corroded, you may be able to salvage it by cleaning the tip with fine sandpaper or an emery cloth. Remove oxidation and restore a shiny surface.

Replace Igniter and Thermocouple

For defective or damaged igniters and thermocouples, replacement is the best option. Always use identical OEM parts. Install according to manufacturer instructions.

Clear Clogged Gas Lines

Carefully blow out obstructed gas tubing with compressed air or purge with propane. Make sure all valves are closed first. Watch for debris exiting the lines.

Clean Flame Sensor

Use steel wool or emery cloth to remove any built-up oxidation on the flame sensor probe. This will allow it to properly detect heat from the pilot flame again.

Replace Gas Valve

If cleaning or adjusting the gas valve doesn’t resolve ignition issues, replacing the valve may be required. Use a universal RV gas valve if an exact OEM match isn’t available.

Flush Water Heater Tank

To remove sediment deposits from hard water usage, flush the tank once or twice per year. Close valves and drain, then refill a few times with fresh water. Use a de-liming solution if mineral buildup is severe.

Reset Control Board

For water heaters with electronic control boards, resetting the board may clear any software glitches preventing proper ignition. Turn power off and on, or remove and reconnect wires.

Get Professional Service

For complex repairs like gas valve replacement or wiring harness issues, it’s best to take the RV to a certified technician. Most gas components require specialized tools and expertise to service properly.

Steps to Light RV Water Heater Manually

Many RV water heaters have a manual lighting option if the electronic ignition fails. Here are the basic steps to light most models manually:

Turn off power to the water heater.
Open the access door and locate the pilot light assembly.
Turn the gas control knob to Pilot position.

Depress and hold knob while applying flame to the pilot tube with a lighter wand.
Continue holding knob down for 30 seconds after lighting pilot.
Release knob and ensure pilot stays lit. Repeat process if pilot goes out.

Turn gas control knob to On position once pilot stays lit.
Replace access panel and restore power to the water heater.

Refer to the user manual for the exact lighting instructions for your make and model. The manual override allows you to use the water heater until the ignition issue can be repaired.

Maintenance to Prevent Problems

Performing regular maintenance can help prevent many water heater ignition issues in the first place:

Inspect anode rod annually – Helps protect against corrosion and sediment buildup inside the tank.
Flush tank yearly – Removes mineral deposits from hard water usage.

Check pressure relief valve – Make sure it isn’t stuck or clogged.
Clean air inlet openings – Prevent debris from obstructing combustion air flow.
Wipe down exterior – Keeps outer surfaces clean and controls free of dust and dirt.

Check wiring and terminals – Ensure all connections are tight to prevent arching or shorts.

Well maintained water heaters are much less likely to have ignition problems. Always consult the user manual for the required maintenance schedule.

When to Call a Professional

Repairs to gas appliances and lines should only be done by qualified technicians. Call a professional RV service center for assistance if:

You smell propane or there are leaks.
Electrical shorts and fires occur.
The gas valve, thermocouple or other safety components need replacement.

Propane regulators, tanks or lines sustain damage.
The appliance doesn’t operate properly after DIY troubleshooting.
You don’t feel comfortable working on gas systems.

Gas systems involve high pressure, flammable fuel and toxic fumes. Don’t hesitate to call an expert rather than tackling a complex repair yourself. Safety should always be the top concern.

Conclusion

An RV water heater that clicks but won’t ignite is a common issue with several possible causes. Start by troubleshooting components like the thermocouple, igniter and gas lines. Simple repairs like clearing obstructions or replacing parts can often get the water heater operating again.

For more complex diagnoses and repairs, rely on a professional RV technician. Proper maintenance is also key to minimize water heater problems and ensure reliable performance season after season. With some diligent troubleshooting and care, your RV water heater will be providing hot showers for years to come.