RV furnace runs for a few minutes then shuts off

RV furnaces follow a sequence: thermostat call, blower start, sail switch proof, ignition, flame sense, heat run, limit protection and shutdown. When the furnace starts and then shuts off after a few minutes, the timing tells you where to look.

If it shuts off before producing heat

If the blower runs, ignition happens briefly, then the burner drops out, focus on flame proving and propane delivery. Dirty burner areas, poor ground, electrode/flame-sensor position, low propane pressure or control-board faults can all cause flame loss.

If it heats first, then shuts off

If the furnace makes heat for several minutes and then stops while the RV is still cold, suspect overheating or airflow restriction. Blocked floor registers, crushed ducts, restricted return air, dust, pet hair, stored items near the furnace or a failing blower can cause the high-limit switch to open.

Check return air and outlets

Make sure cushions, rugs, storage bins and bedding are not blocking return-air grilles or heat registers. RV ductwork is often light and easily crushed. A partially collapsed duct can make one room cold while the furnace overheats near the cabinet.

Low battery voltage can create weird furnace behavior

The furnace blower is 12-volt DC. If voltage drops under load, the blower may not move enough air to close the sail switch or cool the heat exchanger properly. Test battery voltage during the furnace call, not only at rest.

Propane supply still matters after ignition

A weak regulator, nearly empty cylinder, frozen regulator, closed valve, or oil/debris in the propane system can let the furnace light but not burn reliably. Other propane appliances may provide clues, but a furnace uses more fuel than a cooktop burner.

Do not bypass safety switches

Sail switches, limit switches and flame-sense circuits are safety devices. Bypassing them to “test” can create fire or carbon-monoxide hazards. Observe the sequence and use manufacturer-approved tests only.