When your RV furnace blows cold air but won't ignite, the problem is usually a dirty flame sensor, blocked air intake, faulty ignition board, or gas supply issue. Most ignition problems can be diagnosed and fixed with basic cleaning and component checks.
Furnace running 5-10 minutes then quitting usually indicates overheating from restricted airflow, weak flame, or failing control board. Check combustion air intake, propane pressure, and burner flame quality. Control board becomes suspect if other tests pass.
Your Coleman 9420-381 thermostat has failing solid-state switching components causing voltage drop during heating calls. This is a known issue with this model - replace it with a more reliable thermostat or return to a mechanical relay-based unit.
When your RV propane furnace clicks but won't light, it's usually caused by a dirty or failing igniter, blocked air intake, low propane pressure, or faulty control board. Most issues can be resolved by cleaning the igniter, checking propane supply, and ensuring proper airflow.
Furnace rumble and backfire indicates air-fuel mixture problems. Check gas pressure at manifold, deep clean burner by soaking, and inspect heat exchanger. Delayed ignition from weak spark or dirty igniter also causes this. May need replacement on 20+ year unit.
When a Suburban RV furnace only works on battery power but fails to heat on shore power, the issue is typically a converter providing incorrect voltage (13.8V+ instead of 12V) to the control board. The solution involves checking voltage levels and potentially adjusting or replacing the converter.
When upgrading your Suburban KT30 furnace to the 521099 circuit board, you need to properly connect the flame sensor circuit to get continuous spark ignition instead of just one spark. The new board requires different wiring than simply grounding the old flame sensor wire.
Suburban SH-42 thermostat circuit is simple - thermostat closes circuit to allow furnace to run. After thermostat replacement, verify both wires are connected tightly at thermostat and furnace. Test by jumping thermostat wires at furnace - if it starts, wiring or thermostat issue.
Replace Atwood 8535-III with Dometic 8535-IV direct replacement or Suburban NT-30SP alternative.
Furnace blower runs but no ignition usually indicates sail switch, igniter, or gas valve failure. Check sail switch for debris first. Watch for spark at igniter. First run of season may need multiple cycles to purge air.
For a 2002 Born Free with Suburban SF-30 furnace, choose the complete furnace replacement over just the core. While cores cost less, complete units include updated components, better reliability, and easier installation for DIYers.
When your RV furnace clicks but won't ignite, the most common causes are a faulty igniter electrode, blocked burner orifice, or malfunctioning sail switch. Start by checking for proper gas flow and inspecting the igniter for damage or buildup.