Suburban RV Furnace Fan Runs But No Heat

The furnace is the heating source in the RV that is helpful to make the interior warm on freezing nights of winter. These run on both electric and gas sources, mainly propane, to produce warm air.

Suburban RV furnace fan runs, but there is no heat due to weak batteries, damaged sail switch, incorrect setting of the thermostat, obstruction of sail switch, and faulty propane tank regulator. Furthermore, you can face issues due to stuck propane valves, dirty spark probes, failure controller circuit boards, and less gas pressure. 

It is necessary to troubleshoot the furnace as soon as possible when these do not provide warm air because you cannot enjoy the trip in freezing weather.

Suburban RV Furnace Fan Problems Solutions
Weak batteries Connect to shore power or recharge batteries
Damaged sail switch Replace sail switch
Incorrect setting of the thermostat Correctly adjust the thermostat
Obstruction of sail switch Clean the switches with contact cleaners
Faulty propane tank regulator Avid overfilling the propane tank
Failure of the controller circuit board Ensure consistent power supply and check fuse
Lack of gas pressure Refill the propane tank

Weak batteries

You cannot receive warm air from these furnaces because of their weak batteries. The primary purpose of the batteries is to run the fan by supplying power.

The running fans activate the sail switch to provide ignition. The ignition occurs due to the closure of sail switches when fans turn on.

Sometimes the fans do not turn on due to low power or weak batteries, and sail switches cannot supply power to the electric circuit board.

Moreover, the issue comes when shore powers are not connected because this supplies more voltage than batteries and generators.

Connect the RV directly to shore power for high voltage supply. In addition, turn on the generators to recharge the batteries if they are weak and about to die.

Damaged sail switch

The sail switch is the sensitive safety component in most heating systems to reduce fire hazards.

It controls the flow of propane and reduces the risk of fires in the RV. It allows the propane to flow through pipes after detecting the fans’ airflow.

The risk of firing increases when the RV furnace ignites without airflow from the fans or blowers. It does not allow ignition if the fan’s speed is slow to avoid hazardous situations.

The sail switch can get damaged, and you can see only cold air blowing from the heating equipment. These can get damaged due to their age-related deterioration and overtime use.

You should replace these switches and check their wires. These are readily available in markets and at affordable price ranges.

It is better to hire the mechanic for their correct adjustment because you can make the situation worse.

Incorrect setting of the thermostat

It is the small equipment that is present in the furnace to sets the temperature according to the inner environment. These are connected to heating furnaces to change their temperatures.

The thermostat increases or decreases the temperature according to the inner conditions and makes the interior comfortable for people.

You can also set them at a desirable range to receive the maximum heat from the heating devices. Many times people set the thermostat at the incorrect range, and these can turn off after reaching a desirable temperature.

You cannot receive warm air from them because of their incorrect adjustment. Correctly adjust the temperature on them according to your requirement.

Furthermore, you have to change the thermostat if the issue persists after setting the temperature.

Obstruction of sail switch

The obstruction of sail switches is common, hindering their normal functioning.

These can get stuck because of obstructed material on their surface and do not open and close in response to moving fans.

The sail switch’s blade has gaps of a few inches, and dust, dirt, hair, and grease can accumulate there. The accumulated particles restrict their movement, and fans continuously blow cold air.

The dust comes on these switches because of poor cleaning and maintenance of the Suburban RV furnace.

Moreover, the opened doors and windows cause the tiny insects and bugs to come there and make them faulty.

Furthermore, people also take their pets with them during long trips, which can cause their hair and furs to get stuck in these components.

You can clean the sails switches and unclog their obstructions. You can clean them with liquid cleaners or contract cleaners.

Spray the contact cleaners on the affected area and resolve the problem.

Faulty propane tank regulator

The propane regulator valve is present in the tank to control the pressure of the gas. These control the pressure of the gas to protect the connected appliances.

Sometimes this regulator becomes bad and leads to poor control of gas pressure. It causes unusual gas flow and decreases pressure, hindering the ignition mechanism, and you cannot get warm air.

These become faulty due to the presence of moisture in these regulators. The moisture and dust enter the spring area, leading to corroded and rusty valves.

These can also fail to perform their function because of sludge build-up on these valves and poor installation. You can see the freezing of propane due to overfilling and overflowing of the tank.

Check the levels of propane and avoid overfilling in it. Set the tank in the proper position so it cannot lead to freezing and overflowing problems.

Failure of the controller circuit board

The control circuit board is the crucial part of the furnace that allows the gas supply and triggers the ignition procedure to supply warm air from the fans.

Sometimes these circuit boards become bad and restrict the gas supply, and direct spark ignition does not ignite the spark to produce heat.

The controller circuit board fails due to faulty sail switches and high-limit switches that do not supply the power.

Moreover, the issue comes due to a surge in power supply and fluctuations in voltage supply due to bad or weak batteries. The dust and dirt also accumulate on these circuit boards and cause malfunctioning.

The dust accumulates on the circuit board’s insulating layers and produces overheating. You should ensure the correct power supply from the batteries and reset the furnace.

Check the fuses to control fluctuations in the power supply and replace the blown-out fuses.

Lack of gas pressure

Sometimes the direct spark ignition does not ignite and supply warm air due to low gas pressure in the tank.

Therefore, propane gas is stored in small tanks, and their pipes are connected to the respective equipment for their supply.

The pressure decreases when the tank propane levels are low, and these are about to end. Moreover, the reduced pressure issue comes when RVs are not parked at the level ground surface.

The low levels decrease the pressure through pipes and their insufficient supply for ignition.

Check the tank’s propane levels and refill the gas when its levels are low in the tank. Park your RV on the leveled ground surface so it cannot disturb the gas levels.

Check the gas pressure by turning on the other appliances that run on the propane source.

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