It lights and then shuts off after a few seconds, over and over. Is that dangerous?

That is the safety system working, which is the opposite of dangerous — but it does mean something is genuinely wrong, most often flame sensing or an airflow restriction. What matters is not repeatedly cycling it. Every retry admits gas to a chamber that has already failed to run properly.

Could it just be cold weather?

It can contribute. Propane regulators can behave differently in severe cold, and a nearly empty tank in very low temperatures produces reduced vapour pressure. If the fault appears only below a certain temperature and everything works when it warms, that pattern is worth reporting — it points somewhere quite specific.

RV furnace clicks but will not ignite

What this usually means

Clicking or sparking is useful news: the sequence got as far as ignition, which means the blower reached speed and the airflow proof closed. The remaining candidates are all on the gas side — supply, pressure, the valve, or flame sensing — and all of them are technician territory because this is a propane burner inside your living space.

Check this first

Confirm propane is available and flowing by lighting another appliance. A furnace is often the first heavy propane user of the season and regularly takes the blame for a tank that is empty or a valve that is closed.

Drivable, with precautions

Complexity moderate

Cluster Furnace

Stop-work system

A furnace burns propane inside the coach. A fault in the burner, exhaust, or sail switch is a carbon-monoxide risk. Stop and call a technician.

Nothing below is a repair instruction for this system. What follows is what to observe and record — the work itself belongs to a technician.

Most likely causes

Ordered by how often each one turns out to be the answer, with the tell that distinguishes it.

No propane or closed valve
most common
Other propane appliances also fail to light.
Regulator fault or freezing
common
Several appliances misbehave together; worse in very cold weather.
Failed gas valve
common
Ignition sparks correctly, gas is available, and nothing lights.
Igniter or electrode out of position
common
Clicking is audible but no spark reaches the burner.
Obstructed burner after storage
common
Classic seasonal finding; nesting insects in the burner assembly.
Flame sensing failure
common
Lights momentarily, then drops out and retries.

What you can safely check

01
Stop and evacuate on any propane smell
Shut off at the tank from outside if safely reachable, get everyone out, ventilate, and do not operate switches or anything that could spark.
02
Confirm propane at another appliance
The stove is the quickest test. If it lights, propane is present and the fault is at the furnace.
03
Count how many ignition attempts it makes
Most control boards try a set number of times then lock out. Knowing the pattern helps a technician read the board’s behaviour.
04
Note the outside temperature
Regulators can behave differently in severe cold, and a fault that only appears below a certain temperature is a real clue.

What needs a technician

The entire gas side — supply pressure at the appliance, the valve, the burner, the igniter and flame sensing. Pressure is confirmed at the appliance rather than assumed from a full tank, and none of that is owner work on a combustion appliance venting into a living space.

Parts typically involved

So you know what a quote should be naming. We publish no prices — real costs vary by market, season and technician, and a number we invented would look authoritative and help nobody.

Gas valve
Igniter / electrode
Flame sensor
Burner assembly
Propane regulator
Control board

When to stop troubleshooting

You smell propane at any point
It has locked out after repeated attempts — resetting it repeatedly admits gas each time
There is soot around the exterior vent

Can you still travel?

Drivable, with precautions

The coach drives normally, but no heat in freezing weather risks the plumbing as well as comfort. Close the propane at the tank for travel — a sensible habit regardless, and essential if you suspect any gas fault.

Check other symptoms against travel safety

Common questions

It lights and then shuts off after a few seconds, over and over. Is that dangerous?: That is the safety system working, which is the opposite of dangerous — but it does mean something is genuinely wrong, most often flame sensing or an airflow restriction. What matters is not repeatedly cycling it. Every retry admits gas to a chamber that has already failed to run properly.
Could it just be cold weather?: It can contribute. Propane regulators can behave differently in severe cold, and a nearly empty tank in very low temperatures produces reduced vapour pressure. If the fault appears only below a certain temperature and everything works when it warms, that pattern is worth reporting — it points somewhere quite specific.

Related failures

For the whole system rather than this one symptom, see RV furnace repair.

Next step

Work through structured triage for this system and you will end up with a written service brief: what you observed, in what order, and what has not been established yet. It is the document that lets a technician quote properly instead of guessing on arrival.

Being straight about what this is. No technician is signed to any territory yet — not one. We do not match you, dispatch anyone, or promise a call. What you get is the brief, and a request form that copies it to us so we know the demand is real. If you need someone today, take the brief and send it to a local technician directly; it works just as well that way.

Start triage Request a technician