Atwood Hydro-Flame Furnace Won’t Ignite: Troubleshooting and Repair

The Atwood Hydro-Flame furnace not igniting can leave an RV or mobile home without heat and cause stress. This guide explains common causes, step-by-step troubleshooting, safety checks, and proven fixes for Hydro-Flame furnaces, helping users identify whether the issue is a simple restart or requires parts replacement or professional service.

Symptom	Likely Cause	Quick Fix
No spark or click	Burner igniter failure or electrical issue	Check power, fuses, wiring, replace igniter
Clicking but no flame	Bad gas supply, solenoid, or clogged orifice	Check propane tank/valve, regulator, clear orifice
Flame lights then dies	Faulty flame sensor/thermocouple	Clean or replace sensor/thermocouple
Blower runs but no ignition	Control board or thermostat issue	Test thermostat, control board diagnostics

How The Atwood Hydro-Flame Furnace Ignition System Works

The Atwood Hydro-Flame furnace ignition system typically uses a direct spark or hot surface igniter, a gas valve with solenoid, a flame sensing device, a blower, and a control board. When the thermostat calls for heat, the control board powers the igniter and opens the gas valve so the burner lights. The flame sensor confirms combustion and the blower circulates warm air.

Key Components: Igniter or pilot, gas valve/solenoid, flame sensor (thermocouple or flame rod), blower motor, thermostat, and control board.

Safety First: Precautions Before Troubleshooting

Before inspecting the furnace, always turn off the propane supply and disconnect 12V power to the appliance. Work in a well-ventilated area to avoid gas buildup. If a strong propane smell is present, evacuate and ventilate immediately and call a technician.

Important: Working on gas appliances carries risks. If the user is not familiar with gas systems or electrical diagnostics, contact a certified RV technician or gas technician.

Initial Quick Checks

Start with basic checks that often resolve ignition problems quickly. These steps are safe and require minimal tools.

• Verify propane: Ensure the cylinder has gas and the tank valve is open.
• Check regulator and line pressure: Look for frozen or kinked lines and proper regulator function.
• Confirm 12V power: Inspect fuses, battery voltage, and ensure the furnace switch and thermostat are on.
• Check thermostat settings: Set temperature above ambient so the unit receives a heat call.
• Inspect vents and intake: Blocked combustion air or exhaust can prevent ignition or cause safety shutdowns.

Step-By-Step Troubleshooting For Ignition Failure

1. Verify Electrical Power

Many ignition issues stem from low battery voltage or blown fuses. Use a multimeter to check for 12–13.6 volts at the furnace power terminals when the system is active. Replace any blown inline or chassis fuse.

2. Listen And Observe The Ignition Sequence

With power and propane confirmed, engage the thermostat. Note whether the furnace attempts ignition: a clicking or sparking sound usually indicates the igniter is operating. No sound suggests an electrical or igniter fault.

3. Check The Igniter Or Pilot

If the unit uses an electronic igniter, visually inspect for cracks or carbon buildup. For models with a standing pilot, ensure the pilot is lit. Replace a damaged igniter or clean a sooted pilot assembly.

4. Inspect The Flame Sensor Or Thermocouple

If the furnace lights but quickly shuts off, the flame sensor may not detect combustion. Clean the flame rod gently with fine sandpaper and verify correct alignment. Replace the thermocouple or flame sensor if cleaning does not help.

5. Test The Gas Valve And Solenoid

When clicking is present but no flame appears, the gas valve or solenoid may not open. Check for continuity on the solenoid coil and proper voltage during a heat call. If voltage is present but the valve doesn’t open, the gas valve likely needs replacement.

6. Examine The Orifice And Burner Assembly

Debris, spider webs, or soot can clog the orifice and burner ports. Remove and inspect the orifice and burner tubes, clean with compressed air or an approved brush, and replace any corroded parts.

7. Evaluate The Control Board And Safety Switches

The control board coordinates ignition; a failed board may not send the proper signals. Check diagnostic LED codes (if present) and consult the Atwood manual. Also verify limit switches, high-temperature switches, and door interlocks are not tripped or faulty.

Common Causes And Targeted Fixes

Cause	Symptoms	Fix
Empty or closed propane tank	No flame, no gas smell	Open tank, replace cylinder
Low battery voltage	Unit doesn’t attempt ignition	Charge/replace battery, check connections
Faulty igniter	No spark/click	Replace igniter assembly
Clogged orifice	Clicking but no flame	Clean orifice, replace if damaged
Bad flame sensor	Lights then shuts off	Clean/replace sensor
Defective gas valve	No gas flow despite voltage	Replace gas valve/solenoid
Blocked intake/exhaust	Shutdown for safety	Clear vents and ducts

How To Test Specific Components

Testing The Igniter

Observe ignition cycles while listening for a clicking sound. Use a multimeter to check continuity (most igniters will be open at room temp). For hot surface igniters, visually inspect for cracks and replace if damaged.

Testing The Flame Sensor/Thermocouple

Measure millivolts or resistance according to the furnace manual. A weak or zero signal usually indicates replacement. A properly functioning thermocouple should generate a small DC voltage when heated by the pilot flame.

Testing The Gas Valve Solenoid

With the system calling for heat, measure voltage at the solenoid terminal. If the correct voltage is present and the valve does not open, the valve assembly is defective. If no voltage, the control board or wiring is at fault.

Maintenance Tips To Prevent Ignition Problems

• Inspect and clean the burner, orifice, and combustion chamber annually.
• Keep vents, intake, and exhaust clear of debris and nesting insects.
• Replace old or brittle wiring and connectors to ensure good electrical contacts.
• Service the propane system regularly including regulators and hoses.
• Run the furnace briefly before storage to detect issues early.

When To Replace Parts Versus Call A Technician

Simple parts like igniters, orifices, flame rods, and fuses can be replaced by confident DIYers with basic tools and an Atwood parts diagram. Parts requiring gas-tight seals, regulator adjustments, or control board replacements are better handled by certified technicians.

Call a professional if there is a persistent gas odor, regulator failure, complex wiring issues, or if the user is uncomfortable working with gas appliances.

Replacement Parts And Where To Buy

Use OEM (Atwood/Hydor-Flame) or high-quality aftermarket parts for reliability. Common replacement parts include igniter assemblies, gas valves/solenoids, flame rods/thermocouples, orifices, and control boards. Purchase from authorized RV parts suppliers, manufacturer distributors, or reputable online retailers. Verify part numbers against the furnace model plate.

Diagnostic Codes And Resources

Some Hydro-Flame systems include diagnostic LEDs or sequence patterns. Consult the furnace manual for error code meanings and recommended actions. Manufacturer technical bulletins and RV forums can provide model-specific tips and common fixes.

FAQ

Why Does The Furnace Click But Won’t Light?

Clicking indicates the igniter is cycling. The likely issues are no propane supply, clogged orifice, or a stuck gas valve. Check gas supply and clean the burner orifice first.

What Causes The Furnace To Light Then Shut Off?

This usually points to a faulty flame sensor or thermocouple that fails to detect sustained combustion. Cleaning the sensor may help, but replacement is often required.

Is It Safe To Use The Furnace With A Flame Sensor Problem?

No. The flame sensor protects against unburned gas accumulation. A malfunctioning sensor can cause unsafe operation and should be repaired before using the furnace.

Can Low Battery Voltage Prevent Ignition?

Yes. Low voltage can stop the control board from cycling the igniter and gas valve. Ensure the RV battery is charged and connections are clean.

Useful Tools For DIY Troubleshooting

• Multimeter for voltage and continuity checks
• Small screwdriver set and nut drivers
• Fine sandpaper or emery cloth for flame sensor cleaning
• Compressed air or soft brush for burner cleaning
• Manufacturer service manual and parts diagram

Key Takeaways

Systematic troubleshooting—start with propane and 12V, listen for ignition attempts, inspect igniter and flame sensor, test gas valve voltage, and clean orifices. Regular maintenance prevents many Atwood Hydro-Flame furnace not igniting problems. When in doubt about gas or electrical safety, contact a certified RV technician.