RV furnace not working: what fails, in what order, and what it costs

RV furnaces fail in a strict sequence, which makes them one of the easier systems to diagnose over the phone. The blower runs, then a switch proves the airflow, then the board calls for gas, then the igniter fires, then a sensor confirms the flame. Whatever step it stops at tells you what is wrong, and the great majority of these repairs land between $200 and $800.

Check this first (ten minutes)

Confirm the blower runs at all. No blower points at power, a fuse, or the thermostat, not the gas side.
Listen through a full cycle. Blower starts, a pause, then either ignition or a lockout. Note exactly where it stops.
Check propane supply, the same as any gas appliance: tank has fuel, valve open, other propane appliances working.
Look at the exterior intake and exhaust vents for blockage: debris, a nest, or snow buildup after a storm can all restrict them.
If it runs but never fully warms the rig, note whether it cycles rapidly or runs continuously without reaching the thermostat setpoint, which points toward output rather than ignition.
Check the thermostat location and setting, since a thermostat placed somewhere that reads warmer or cooler than the rest of the rig gives a misleading picture.

What is usually wrong

What you notice	Likely cause	Fix and cost
Blower doesn’t run at all	Power, fuse, or thermostat issue	$150 to $350
Blower runs, no ignition attempt	Sail switch not proving airflow	$200 to $400
Ignition attempts, no flame	Blocked burner, failed igniter, or low gas pressure	$200 to $500
Lights, then shuts off	Limit switch or a flame sensor fault	$200 to $500
Runs but never fully warms the rig	Under-jetted for elevation, or a partly blocked burner	$150 to $350
Blocked exterior vent (intake or exhaust)	Debris, nest, or snow buildup	$150 to $300 to clear and inspect

These sit inside the appliance repair range on the pricing page, on top of the $75 to $150 trip fee and $125 to $190 hourly labor.

Why elevation matters for furnace output specifically

Propane furnaces are rated for combustion at a given air density, and the national fuel gas code calls for roughly a 4 percent reduction in appliance input for every 1,000 feet of elevation above 2,000 feet. At Prescott’s roughly 5,400 feet, a furnace set up without accounting for that can genuinely underperform, cycling a lot while never quite bringing the rig up to temperature, even though every component in the ignition sequence works correctly. That is a burner-sizing check, not a repair for a broken part, and it is worth ruling in or out before assuming the furnace itself has failed.

Where we work

On site across Prescott, Prescott Valley, Chino Valley, Dewey-Humboldt, Williamson Valley, Paulden, and Mayer. The appliance repair service page covers the full scope, and the maintenance and winterization page covers the pre-winter check that catches furnace problems before the first hard freeze.

Frequently Asked Questions

My RV furnace blows cold air and never lights. What is wrong?

The blower running without ignition points at the sequence after the fan: usually the sail switch that proves airflow, a blocked burner or exhaust, a failed igniter or board, or low propane pressure. A blocked exhaust from debris or a nest is a genuinely common cause.

How much does RV furnace repair cost in Prescott?

$200 to $800 covers the great majority: sail switches, limit switches, igniter boards, gas valves, and blower motors. Full furnace replacement is a larger conversation and rarely necessary if the blower and heat exchanger are sound.

My furnace runs constantly but never fully warms the rig. Is that an elevation problem?

It can be. Propane furnaces built or tuned for a lower elevation can be under-jetted for Prescott's roughly 5,400 feet and simply not producing their full rated heat output, which looks like a furnace that runs but can't keep up. A furnace altitude check and re-jet is a smaller repair than replacing the unit.

Do I need the furnace as much here as people think?

More than most owners expect coming from the desert. Prescott's climate record shows about 128 nights a year at or below freezing, with January lows averaging in the mid-20s. An RV holds heat poorly, so the furnace is doing real work most winter nights, not just an occasional cold snap.