The Atwood Hydro Flame Furnace is a reliable and widely used heating system in recreational vehicles (RVs) and trailers. Its efficient performance ensures a cozy and comfortable living space for RV enthusiasts during colder seasons. However, like any mechanical equipment, the furnace may encounter problems over time. In this comprehensive guide, we will explore common issues that can arise with the Atwood Hydro Flame Furnace and provide detailed troubleshooting solutions to help you keep your heating system in optimal condition.
1. Furnace Not Turning On
Possible Causes:
- Thermostat Malfunction: The thermostat plays a crucial role in the furnace’s operation by sensing the ambient temperature and signaling the furnace to turn on when the temperature falls below the set level.
- Power Supply Issues: A malfunctioning power supply can prevent the furnace from turning on. Loose connections, blown fuses, or tripped circuit breakers are common culprits.
Troubleshooting Steps:
- Check Thermostat Settings: Begin by verifying the thermostat settings. Ensure that it is set to the appropriate temperature and mode, such as “heat” or “auto.” Adjust the settings and see if the furnace responds.
- Test Thermostat Operation: To test the thermostat’s functionality, use a multi-meter. Disconnect the thermostat from the furnace and measure continuity across its terminals while adjusting the temperature settings. If there is no continuity or inconsistent readings, consider replacing the thermostat.
- 1.2.1 Inspect Power Supply: Carefully examine the power source for any issues. Look for loose wires, damaged cords, or blown fuses. If you find any problems, rectify them and attempt to start the furnace again.
- 1.2.2 Reset Circuit Breakers: If the furnace is not receiving power, check the RV’s circuit breaker panel for any tripped breakers. Reset them and see if it resolves the problem. If the circuit keeps tripping, there may be an underlying electrical issue that requires professional attention.

2. Insufficient Heating or Uneven Heating
Possible Causes:
- 2.1 Clogged or Dirty Furnace Burner: Over time, the furnace burner can accumulate dirt, debris, and rust, hindering its ability to produce sufficient heat.
- 2.2 Blocked Vents or Airflow Obstruction: Obstructed vents or airflow pathways can lead to inadequate heat distribution throughout the RV.
Troubleshooting Steps:
- 2.1.1 Clean the Furnace Burner: Start by turning off the furnace and gas supply before attempting to clean the burner. Gently brush away any debris and use compressed air to blow out dirt and dust. Avoid using sharp objects that may damage the burner.
- 2.1.2 Inspect the Burner for Damage: During the cleaning process, check the burner for signs of corrosion or damage. If the burner is severely corroded, it’s best to replace it to ensure efficient heating.
- 2.2.1 Check Vents and Airflow: Inspect the exterior vents for any blockages, such as leaves, insects, or other debris. Clean the vents and ensure nothing obstructs the airflow. Additionally, check the interior vents and ducts for any blockages.
- 2.2.2 Verify Ducting Integrity: Examine the ductwork for any leaks or disconnected sections that may disrupt the airflow. Repair or replace damaged ducts to improve heating efficiency and even heat distribution.
3. Continuous Fan Operation
Possible Causes:
- 3.1 Fan Limit Switch Malfunction: The fan limit switch is responsible for turning the blower fan on and off based on the furnace’s internal temperature. If this switch malfunctions, the fan may run continuously.
Troubleshooting Steps:
- 3.1.1 Test the Fan Limit Switch: Locate the fan limit switch and use a multi-meter to check for continuity across its terminals. With the furnace running, observe the temperature readings. If the fan limit switch fails to shut off the fan when the temperature rises to the appropriate level, the switch may be faulty and require replacement.
- 3.1.2 Adjust Fan Limit Settings: Some fan limit switches have adjustable settings. Refer to the furnace’s manual to determine the correct settings and make adjustments as needed. If the settings are beyond repair, replace the fan limit switch.
- 3.1.3 Seek Professional Assistance: Working with electrical components can be hazardous if not done correctly. If you are uncertain about dealing with the fan limit switch or any other electrical aspects of the furnace, seek help from a qualified RV technician to avoid any safety hazards.

4. Unusual Furnace Noises
Possible Causes:
- 4.1 Squealing or Screeching Sounds: These noises may indicate a problem with the blower motor or fan. Worn-out bearings or damaged fan blades are common causes of such noises.
- 4.2 Banging or Rumbling Sounds: Such noises might suggest an issue with the furnace’s ignition or gas combustion. Delayed ignition or unburned gas can cause loud banging or rumbling sounds.
Troubleshooting Steps:
- 4.1.1 Lubricate the Blower Motor: Apply lubricating oil to the blower motor’s oil ports to reduce friction and eliminate squealing noises. Proper lubrication can extend the life of the motor and prevent premature wear.
- 4.1.2 Inspect and Clean the Fan Blades: Check the fan blades for any debris or damage. Clean the blades and ensure they are securely attached to the motor. If the fan blades are damaged, replace them to avoid further noise issues.
- 4.2.1 Check the Igniter and Burner: Inspect the igniter for signs of wear or damage. Clean or replace it if necessary to ensure proper ignition. Additionally, examine the burner for any obstructions or damage that could cause incomplete combustion and loud noises.
- 4.2.2 Adjust the Gas Pressure: If you hear rumbling sounds during ignition, the gas pressure might be too high. High gas pressure can lead to disruptive combustion. Adjust the pressure to the manufacturer’s recommended levels or consult a professional if unsure about gas-related adjustments.

5. Furnace Short Cycling
Possible Causes:
- 5.1 Dirty or Defective Flame Sensor: A dirty or faulty flame sensor may cause the furnace to short cycle, turning on and off repeatedly.
- 5.2 Improper Thermostat Placement: If the thermostat is placed near a heat source or in direct sunlight, it might inaccurately sense the temperature, leading to short cycling.
Troubleshooting Steps:
- 5.1.1 Clean the Flame Sensor: Turn off the furnace and remove the flame sensor. Gently clean it with fine sandpaper or steel wool to remove any residue or corrosion that may be interfering with its proper function.
- 5.1.2 Test Flame Sensor Functionality: Use a multi-meter to check for continuity across the flame sensor’s terminals while the furnace is running. The sensor should generate a small electrical current when exposed to the flame. If there is no continuity or inconsistent readings, consider replacing the flame sensor.
- 5.1.3 Check Flame Sensor Alignment: Ensure that the flame sensor is correctly positioned relative to the burner flame. A misaligned flame sensor may not detect the flame properly, causing short cycling.
- 5.2.1 Relocate the Thermostat: If the thermostat is near a heat source or in direct sunlight, it may not accurately detect the actual ambient temperature. Relocate the thermostat to a more suitable location within the RV to prevent short cycling.
- 5.2.2 Calibrate the Thermostat: Some thermostats allow calibration to improve their temperature reading accuracy. Refer to the manufacturer’s instructions to calibrate the thermostat correctly.
Conclusion
By following the detailed troubleshooting steps outlined in this comprehensive guide, you can effectively address common issues that may arise with the Atwood Hydro Flame Furnace in your RV. Regular maintenance, cleaning, and prompt attention to problems will ensure that your heating system operates efficiently, keeping you warm and comfortable during your travels.
However, if you encounter complex issues or feel uncomfortable performing certain tasks, don’t hesitate to seek professional assistance from a qualified RV technician to ensure the safe and reliable operation of your furnace. Remember that proper maintenance and care of your Atwood Hydro Flame Furnace will extend its lifespan, allowing you to enjoy the comfort of a cozy RV no matter the weather outside.