RV furnaces run through the same steps every time: the blower starts, the igniter fires, the gas valve opens, the burner lights and the blower keeps running. If the cycle stops, note which step it reached. That narrows the problem a lot before you touch anything.
⚠️ Safety First
- If you smell propane, put everyone outside, shut the tank valve, avoid switches and flames, and call your propane supplier or emergency services.
- Never bypass a safety switch to get heat. They protect against fire and carbon monoxide.
- Keep a working carbon monoxide and propane detector in the RV and test them before every trip.
- Repairs to gas components — the valve, regulator and lines — should be done by a qualified technician. Rules vary by province.
🧰 Tools & Materials
- Multimeter
- Soft brush and vacuum
- Fine abrasive pad (for the flame sensor)
- Screwdriver set
- Your furnace model’s manual and wiring diagram
📋 Step by Step
1 Check the basics
Most “dead” furnaces are a supply problem.
- Confirm the thermostat is on heat and set above room temperature; replace its batteries if it has them.
- Measure 12 V at the furnace while the blower tries to run. Low voltage is a very common cause.
- Check the propane tank valve is open and the tank isn’t nearly empty, and that the stove still lights.
2 Read the sequence
Match what you hear to the stage.
- Blower never starts: power, fuse, thermostat or blower motor.
- Blower runs, no clicking: control board, airflow-proving switch or igniter circuit.
- Clicks but no flame: propane supply, gas valve or igniter spacing.
- Lights, then shuts off within seconds: dirty flame sensor or poor ground.
- Runs, then cycles off repeatedly: overheating — look at airflow.
3 Clear the airflow
Blocked air makes the high-limit switch shut the furnace down.
- Free the return-air grille and every duct register of stored items.
- Check the exterior intake and exhaust vents for snow, ice, leaves and insect nests.
- Look for crushed or disconnected ducts under beds and benches.
4 Clean the burner area
Spider webs and soot are common culprits.
- Turn off power and propane first.
- Vacuum dust and webs from the burner tube and combustion chamber.
- Gently clean the flame sensor rod with a fine abrasive pad and wipe it dry; reinstall it exactly as it was.
5 Know where DIY ends
Gas and combustion problems need the right tools.
- A technician measures supply pressure with a manometer (typically around 2.7 kPa, or 11 inches of water column).
- If several propane appliances run weakly, the regulator is the likely cause.
🔧 When to Call a Professional
Stop and book a qualified technician if you see any of these:
- Any smell of propane or soot, or a yellow, lazy flame
- Weak flame on every propane appliance
- Repeated lockouts after cleaning
- A cracked heat exchanger or damaged vent
❄️ Furnaces in hard cold
Propane still vaporizes at very low temperatures, but a nearly empty tank or a small cylinder can struggle to keep up in a long cold snap. Keep tanks well above empty, clear ice from exhaust vents, and plug into shore power if you can — a furnace blower can drain a battery overnight.
🔎 Furnace Symptoms and Next Steps
| Symptom | Possible cause | Safer next step |
|---|---|---|
| Blower runs but no heat | Ignition lockout, propane supply or sail-switch issue | Check user controls; consult technician |
| No blower | Low 12V voltage, fuse or thermostat issue | Check battery state and accessible fuse |
| Short cycling | Blocked airflow or thermostat placement | Clear vents; seek service if recurring |
🍁 Cold-weather furnace use
Check the battery voltage, thermostat, vents and propane supply first. Ice or snow around the exhaust can block airflow, so keep vents clear.
📚 More Guides on This Topic
- Furnace not starting or blowing cold air – symptom-based checks
- Heating an RV in a Canadian winter – heat planning and carbon monoxide safety
- Carbon monoxide safety – alarms and ventilation
- Propane regulators and changeover – fuel supply problems