Atwood Furnace Reset Switch: Troubleshooting, Replacement, and Maintenance

The Atwood Furnace Reset Switch is a small but critical component that protects RV and marine furnaces by shutting down the unit during overheating or electrical faults. This article explains how the reset switch works, common failure symptoms, step-by-step troubleshooting, replacement tips, compatible parts, safety precautions, and cost considerations to help owners restore reliable heating.

Item	Details
Function	Overheat/thermal protection and manual reset
Common Location	On furnace housing near blower or heat exchanger
Typical Symptoms	No heat, intermittent operation, visible burn marks
Typical Replacement Cost	$10–$60 for part; $50–$150 labor if professional

How The Atwood Furnace Reset Switch Works

The Atwood reset switch, often called a thermal cutoff or manual reset thermal switch, senses excessive temperature or an overcurrent condition in the furnace. When the sensed value exceeds a safe threshold, the switch opens the circuit to stop the gas valve or blower, preventing damage or fire.

In many Atwood furnaces, the reset switch is a physical push-button mounted on or near the furnace housing. Once trips occur, the switch must be manually depressed to restore power after the underlying fault is corrected.

Common Causes For Reset Switch Tripping

Understanding causes helps prevent repeated trips. Common triggers include restricted airflow, clogged filters, failed blower motor, blocked flue or vent, malfunctioning gas valve, loose wiring, or a failing high-limit sensor.

Restricted Airflow: Accumulated dust, lint, or debris in intake grills and ducts raises heat in the heat exchanger, causing the thermal cutoff to trip.

Blower Or Motor Issues: A failing blower that does not move sufficient air allows heat to build. Mechanical binding or bearing failure can create excessive current draw, triggering the reset.

Blocked Exhaust Or Vent: Obstructions in the flue, bird nests, or ice can prevent proper venting, backpressure raises furnace temperatures, and the switch trips.

Electrical Problems: Loose connections, corroded terminals, and shorted wiring can cause voltage irregularities or overcurrent that trips the thermal switch.

Symptoms Indicating A Faulty Reset Switch

Several symptoms point to the reset switch itself failing rather than an external fault. Key signs include a switch that won’t latch, visible physical damage like burn marks, or a unit that trips instantly after resetting without running long enough to overheat.

If the furnace shows no diagnostic codes, the blower runs but the burner won’t ignite, or the reset button feels mushy or stuck, the switch may be defective and require replacement.

Tools And Safety Equipment Needed

Before servicing an Atwood furnace and reset switch, gather common tools and safety gear to ensure a safe and efficient repair.

• Insulated screwdrivers and nut drivers suitable for furnace fasteners
• Multimeter for continuity and voltage checks
• Needle-nose pliers and wire strippers
• Replacement reset switch compatible with the furnace model
• Protective gloves, safety glasses, and a dust mask
• Manufacturer schematic or service manual for wiring reference

Step-By-Step Troubleshooting Procedure

Follow a systematic approach: isolate power, inspect visually, test electrically, verify airflow and venting, and replace the switch only after determining it’s necessary.

1. Power Isolation And Visual Inspection

Disconnect 12V power and, if applicable, propane supply before opening the furnace access panels. Check the reset switch and surrounding area for soot, melted insulation, or discoloration that suggests overheating.

2. Check Airflow And Filters

Inspect intake vents, return air grills, and furnace filters. Clean or replace filters and remove any obstructions in ducts, grills, and the combustion air intake to restore proper airflow.

3. Test The Blower Motor

Reapply power briefly to test the blower. If the blower fails to operate, measure voltage at the motor and current draw with a clamp meter. Abnormal readings indicate motor or wiring faults that can trip the reset switch.

4. Inspect Exhaust And Venting

Ensure the flue and vent piping are clear of debris, nests, snow, and ice. Verify proper installation and slope of vent pipes to prevent backflow or condensation buildup that can affect operation.

5. Electrical Tests On The Reset Switch

With power off, disconnect the reset switch and test continuity with a multimeter. A normally closed thermal switch should show continuity; if open at ambient temperature it is defective. Also inspect terminal tightness and wiring condition.

6. Recreate Conditions Carefully

If safe, apply power and observe operation after clearing any issues. If the switch trips immediately without the furnace running long enough to overheat, that supports replacing the switch or addressing an electrical short.

Replacing The Atwood Furnace Reset Switch

Replacement requires identifying the correct OEM or compatible part and following safe installation practices. Incorrect parts or improper wiring can create hazards.

Selecting The Correct Replacement Part

Consult the furnace model number found on the data plate and the Atwood/Suburban parts diagram. Common part numbers vary by model and year; verify temperature rating and mounting style before purchase. Aftermarket replacements are available but choose high-quality components with matching specs.

Removal And Installation Steps

Turn off all power and propane. Remove the furnace access panel to reach the reset switch. Note wire locations or photograph the wiring for reference. Disconnect wires using insulated tools, remove the mounting fastener, and extract the old switch.

Install the new switch in the same orientation, secure mounting hardware, and reconnect wires to the original terminals. Reassemble the furnace panel and restore power. Confirm normal operation and that the switch latches correctly when pressed.

Safety Precautions When Working With Furnaces

Working on a gas or electric furnace carries fire, electrical shock, and carbon monoxide risks. Always follow safety protocols and local codes.

• Shut off propane and battery power before servicing gas components.
• Work in a well-ventilated area and check for gas leaks after reassembly.
• Use insulated tools and avoid working alone when handling gas systems.
• If unsure, hire a certified RV technician or HVAC technician.

When To Call A Professional

Situations that require professional service include persistent trips after replacing the switch, suspected gas valve failures, major wiring faults, flue corrosion, or any uncertainty about safe disassembly and reinstallation.

Technicians can perform advanced diagnostics, leak tests, combustion analysis, and full component replacements to restore safe operation and ensure compliance with safety standards.

Cost Considerations And Typical Pricing

The cost to replace an Atwood furnace reset switch is modest for parts but can increase if professional labor is required. Typical prices for OEM or high-quality replacement switches range from $10 to $60.

Labor costs for a professional technician often fall between $50 and $150 depending on travel, hourly rates, and diagnostic effort. If additional components fail, total service costs may be higher.

Preventive Maintenance To Avoid Future Trips

Regular maintenance reduces reset switch trips and extends furnace life. Recommended tasks include cleaning intake and exhaust vents, replacing or cleaning filters, and performing annual inspections before cold weather.

• Inspect vent terminations and clear debris seasonally.
• Lubricate blower motor bearings if serviceable and recommended in the manual.
• Check wiring for corrosion, loose terminals, and chaffing during each service interval.
• Run the furnace briefly in spring and fall to verify operation and catch issues early.

Common Myths And Misconceptions

Several misconceptions lead owners to unnecessary repairs. One myth is that repeatedly resetting the switch is harmless. In reality, repeated trips indicate an unresolved fault and can mask dangerous conditions.

Another misconception is that aftermarket switches always match OEM performance. Mismatched temperature ratings or poor build quality can cause premature trips or fail to protect the furnace properly.

Compatible Parts And Cross-References

Atwood furnaces are branded across RV and marine applications; parts may be cross-referenced with Suburban and Dometic in some cases. Always cross-check the furnace model and part number when ordering replacements. Manufacturer parts diagrams and service manuals are the best sources for exact matches.

Quick Troubleshooting Checklist

• Verify power and propane supply to the furnace.
• Inspect and clear intake and exhaust vents.
• Check blower operation and current draw.
• Test reset switch continuity at room temperature.
• Replace the switch only after eliminating airflow and motor faults.
• Retest furnace operation and ensure no gas leaks.

Useful Resources And Manuals

Owners should keep the furnace model number handy and consult the Atwood/Empire or Suburban service manuals for wiring diagrams and parts lists. Manufacturer technical bulletins often include updates and recommended procedures for common failures.

Online RV forums, official parts retailers, and certified HVAC technicians provide additional troubleshooting tips and parts sourcing assistance.

Note: When in doubt about gas-system repairs or electrical abnormalities, engage a certified technician to ensure safety and compliance with codes.