3 Most Common Keystone RV Furnace Troubleshooting

Keystone RV Furnace Troubleshooting

Knowing how to do Keystone RV furnace troubleshooting should help you regain a warm and cozy RV interior for your family.

Keystone RVs are renowned for providing comfort and adventure for nature-loving families, but even the best RVs can experience issues with their space heating systems.

Dirt, wiring issues, and everything in between can prevent you from having a comfortable RV cabin when it’s freezing outside. So, how do you troubleshoot a Keystone RV furnace? Read on.

Common Keystone RV Furnace Issues


Before we dive into Troubleshooting Keystone RV furnaces, let’s familiarize ourselves with the most common issues experienced by owners so you can plan your approach more systematically.

1. It Won’t Start


A common complaint is the Keystone RV furnace not turning on. The most likely culprit is a loose or damaged electrical wire connection. Most RV furnaces have an electronic igniter. Hence, a broken igniter can also explain why the RV furnace won’t ignite.

However, a problematic ignition sensor, thermocouple, pilot tube, and other components can also explain a Keystone RV furnace not working as it should.

2. It Doesn’t Heat Up

Sometimes, the problem isn’t in the ignition but the heating mechanism. Thermostat problems are the most common culprit, although a sensor issue could also account for the problem.

Sail or flow switch issues, blower problems, and thermocouple faults can also cause a Keystone RV furnace to ignite but not produce heat.

3. Insufficient or Inconsistent Heating


Your Keystone RV heater lights and heats up, but its warmth is inconsistent or insufficient.

If this happens, this might point to a fault in different furnace components, including the blower, restrictor valve, pilot light tube, sensors, and thermocouple.

Troubleshooting Guide


Like everything else, troubleshooting a Keystone RV furnace requires reading the Keystone RV furnace manual. As a Thor Industries subsidiary, Keystone provides a troubleshooting guide for its RV owners. If you misplaced the manual, please consider the following.

1. Check the RV Furnace’s Fuse


The fuse might be tiny, but it’s crucial to optimal furnace operation. It’s like a bridge between the power source and the RV space heater, breaking a thin wire to prevent electrical catastrophes.

Unfortunately, some Keystone RV owners complain of the fuse popping out of its receptacle.

Check the fuse and see if it’s in its correct position. If not, remove it and slightly press the connections to ensure a firmer fit in the receptacle. Reinsert the fuse into its slot and check the furnace’s operation.

2. Assess the Furnace’s Electrical System


Suppose the fuse is okay, but the Keystone RV furnace is still not lighting up. What should you do then?

  • Inspect the electrical wires running between the RV furnace and its power supply, including associated components (i.e., blower motor and 12V battery), for signs of damage.
  • Note down the loose connections. Try to tighten fasteners to secure wire ends to their respective terminals.
  • Assess the RV furnace’s electrical circuit using a multimeter. You will want a stable 12-volt current, not fluctuating or below 12 volts. Check the switch’s power, ensuring the electricity flowing to it is adequate.
  • Test your 12V-battery’s charge if your RV furnace relies on DC power. Insufficient battery charge might explain why the Keystone RV furnace doesn’t start.
  • Please check the air filters for obstruction. Dirt and other particulates can accumulate on the surface, blocking airflow and causing the blower motor to overheat. Extremely high temperatures can undermine electrical wire integrity and blow a fuse.

We don’t recommend fixing RV electrical problems unless you’re confident with your electrical skills. This activity is best for a licensed RV electrician.

  • Inspect the thermostat

Some Keystone RV owners overlook a furnace thermostat’s setting, causing the heater to produce insufficient heat. In most instances, users switch the thermostat to a lower temperature, creating a cooler, not warmer, environment.

Check the thermostat’s setting, ensuring it’s within your preferred temperature.

Determine the thermostat’s location. If this device is near a “warm” place (i.e., near sunlight), there’s a chance it will interpret the RV cabin temperature as “warm.” It will cause the thermostat to adjust the temperature settings lower than necessary.

Reposition the thermostat so it’s far from radiant heat. It should be angled (90 degrees) toward the floor, several feet from the surface.

Clean the thermostat’s surface because dust can impair its sensing abilities.

3. Assess the Pilot Light Sensor or Thermocouple


Some Keystone RV furnaces have a flame sensor, while others use thermocouple. Regardless of the mechanism, these devices allow the gas valves to stay open as long as there’s light in the burners.

Carbon particles can easily accumulate on these devices’ surface. Their position in the furnace can also be problematic. For example, increased exposure to airflow can cause the flame sensor or thermocouple to work inconsistently.

So, cleaning the thermocouple should clear the surface of carbon deposits.

Inspect the thermocouple or flame sensor for signs of rust or corrosion. If you spot any, rubbing the corroded surface with sandpaper should restore these devices’ function.

Unfortunately, if cleaning doesn’t solve the problem, you can consider replacing the thermocouple or flame sensor.

4. Check the Flow Switch


Keystone RV furnaces have a flow switch (also called vane or sail switch) that ensures proper space heater function relative to the blower’s performance.

The flow switch allows the furnace to keep burning because it senses sufficient combustion air.

Unfortunately, flow or vane switches are not indestructible. Wear and tear can hamper the device’s normal operation, creating a safety hazard for the RV and its occupants.

This furnace component draws its power from the RV 12-volt battery.

  • Hence, your first action is to double-check the battery’s charge level using a multimeter or voltmeter.
  • Try swapping your battery with a fully charged unit and check to see if the flow switch functions. Alternatively, you can recharge the battery if you don’t have a spare.
  • You might want to reassess the wires to see if the battery has sufficient charge. Chewed out, frayed, and damaged cables can prevent electricity from reaching the vane switch. Replacing these wires shouldn’t be challenging.
  • Inspect the furnace air vents, noting backflow. A normally functioning vane switch will create a backdraft, underscoring optimal blower operation. Without this backward airflow, you can suspect improper ignition despite normal blower function.
  • Lastly, consider checking the gas supply. The vane switch will also fail if it doesn’t receive sufficient propane gas through the pipes and valves.

Defective flow switches require replacement. Although it might sound simple, the process is often more technical than most RV owners imagine. You might need an expert in disassembling the RV furnace to access and replace the faulty vane switch.


Keystone RV furnace troubleshooting is never an easy task. This space-heating appliance has many components that can go “bad” and undermine its operation, leaving you and your family cold inside the RV.

However, with the right approach, you can identify and resolve common issues. Although RV furnace issues are few, their potential causes can make problem-solving challenging. You might think it’s a wire issue, when the real culprit is dirt or dust.

Professional RV technicians might cost more than a DIY strategy. However, RV owners can only do so much to restore their Keystone RV furnace’s functionality.

5/5 - (2 votes)