The Dometic furnace reset switch is a small but critical component that helps protect RV and marine furnaces from overheating and electrical faults. This guide explains how the reset switch works, how to locate and reset it safely, common causes for trips, diagnostic tips, parts and replacement guidance, and when to call a technician. It focuses on practical, step-by-step information for U.S. users who own Dometic heating systems.
| Issue | Likely Cause | Quick Action |
|---|---|---|
| Furnace Won’t Start | Tripped Reset Switch / No Power | Check battery/breakers; press reset |
| Furnace Starts Then Stops | Overheat Or Blocked Flue | Inspect vents; reset after cool-down |
| Repeated Trips | Faulty Switch Or Wiring | Test/reset; replace if persistent |
How The Dometic Furnace Reset Switch Works
The Dometic furnace reset switch is typically a manual or automatic thermal protector located on the furnace housing or control board that interrupts power if the unit overheats or experiences an electrical fault. Its primary role is to prevent damage and fire risks by cutting power until conditions are safe. Many Dometic furnaces incorporate a small push-button reset or a replaceable thermal fuse depending on the model.
Where To Find The Reset Switch On Dometic Furnaces
On most Dometic RV and marine furnace models, the reset switch sits on the furnace access panel or near the blower motor. For compact units, the switch may be inside the control box requiring panel removal. The owner’s manual lists the exact location, and the reset is often labeled “Reset” or appears as a small red push-button.
Safety First: Before Attempting A Reset
Before interacting with the Dometic furnace reset switch, disconnect power sources to avoid electrical shock and reduce risk of fire. Turn off the propane supply if applicable, disconnect batteries, and switch off shore power or generator. Allow the furnace to cool for at least 10–15 minutes after operation to avoid burns or repeated trips from residual heat.
Step-By-Step Guide To Resetting A Dometic Furnace Reset Switch
These steps cover a standard manual push-button reset procedure. Models with thermal fuses require replacement rather than resetting.
- Power Down: Turn off shore/generator power and disconnect battery ground to ensure no voltage at the furnace.
- Cut Fuel: Shut off the propane supply when working on a propane-fed furnace.
- Access The Switch: Open the furnace access panel using proper tools. Locate the reset button—usually red and recessed slightly.
- Inspect Surroundings: Check for loose wires, visible corrosion, burnt connectors, or debris that could cause overheating or electrical arcing.
- Press The Reset: If the switch is a push-button, press firmly until it clicks. Do not depress repeatedly if there’s strong resistance.
- Restore Power And Fuel: Reconnect batteries and power, open propane if used, and attempt furnace startup following the normal sequence.
- Monitor Performance: Run the furnace through a full cycle and watch for proper ignition and stable operation. If the reset button trips again, proceed to diagnostics or replacement.
Common Reasons The Dometic Furnace Reset Switch Trips
Understanding why the reset switch tripped helps prevent recurrence. Common causes include:
- Overheating From blocked intake or exhaust vents or dirty heat exchangers.
- Electrical Faults Such As shorted wiring, corroded connectors, or failing blower motors drawing excess current.
- Faulty Switch Mechanical wear or internal failure can cause nuisance trips.
- Restricted Airflow Closed vents, clogged filters, or insulation too close to the furnace cabinet.
- Propane Or Gas Issues Improper combustion causing high temperatures or incomplete ignition sweeps.
Diagnostic Checklist If Reset Button Trips Repeatedly
If the Dometic furnace reset switch continues to trip, use this prioritized diagnostic checklist to identify the root cause.
- Verify proper power voltage at the furnace with a multimeter; low voltage can cause motor strain and trips.
- Inspect intake and exhaust vents for obstructions, nests, ice, or debris and clear any blockages.
- Examine the blower motor for abnormal noise or overheating; a failing motor often creates trips.
- Check furnace wiring for burnt insulation, loose terminals, or corrosion and repair or tighten connections.
- Remove and inspect the heat exchanger area for soot buildup or debris; excessive soot indicates combustion issues.
- Test the thermostat and control board for fault codes; Dometic models may use LED flash patterns to indicate specific problems.
Testing The Reset Switch And Electrical Components
Testing helps determine whether the reset switch or another component is faulty. Recommended tests:
- Continuity Test: With power off, use a multimeter to test continuity across the reset switch; an open circuit when the switch is in the normal position indicates a failed switch.
- Voltage Under Load: Measure voltage at the furnace during startup to detect dropouts that strain components.
- Current Draw: Use a clamp meter to measure blower motor current; readings significantly above spec suggest motor or capacitor problems.
Replacement Options For The Dometic Furnace Reset Switch
If testing indicates a failed reset switch, replacement is often straightforward. Dometic replacement parts are available through authorized dealers, RV parts stores, and online retailers. Options include:
- OEM Reset Switch Assembly Specific To Furnace Model
- Aftermarket Compatible Thermal Cutouts Or Reset Buttons
- Complete Control Board Replacements If The Switch Is Integrated
A replacement part number can be confirmed via the furnace model plate or the owner’s manual. Using OEM parts ensures compatibility and safety.
Estimated Costs And Typical Turnaround
Costs vary depending on the part and whether a technician performs the work. Typical ranges:
| Item | Estimated Cost (USD) | Notes |
|---|---|---|
| Reset Switch (OEM) | $10–$40 | Simple push-button replacements |
| Thermal Fuse/Thermostat | $15–$60 | May require partial disassembly |
| Control Board | $120–$350 | Integrated electronics; pricier |
| Professional Service Call | $100–$300 | Labor and diagnostics vary by region |
DIY Replacement Steps For A Push-Button Reset Switch
When comfortable with basic electrical work, follow these steps for a push-button replacement. If uncertain, hire a qualified RV technician.
- Power Down And Ventilate The Area; close propane only after shutting off electrical power to prevent accidental ignition.
- Remove The Access Panel And Identify The Switch Assembly; document wiring positions with photos before disconnecting.
- Disconnect Wires And Remove Mounting Hardware; avoid pulling on wires—use the connectors.
- Install The New Switch And Reconnect Wires To Original Positions; ensure tight, clean connections.
- Restore Power And Test The Furnace Operation; watch for stable ignition and no further trips.
When To Call A Professional
Professional service is advised if any of the following apply: repeated reset trips after replacement or inspection, evidence of gas leaks, suspected control board failure, difficulty accessing the switch, or lack of electrical diagnostic tools. A certified RV technician or HVAC technician with experience on Dometic systems can perform safe, compliant repairs and check combustion safety.
Preventive Maintenance To Avoid Future Trips
Regular maintenance reduces the likelihood of reset switch trips. Recommended actions:
- Inspect and Clean Intake/Exhaust Vents Seasonally
- Remove Debris Around The Furnace Compartment
- Change Or Clean Air Filters As Applicable
- Service The Blower Motor And Replace Worn Bearings
- Schedule Annual Professional Combustion And Safety Checks
Model-Specific Notes And Owner’s Manual Tips
Dometic manufactures many furnace models such as the B-series and the S-series with varying reset switch configurations. Always consult the specific model owner’s manual for wiring diagrams, part numbers, and recommended test procedures. Manuals are available on the Dometic website or through authorized dealers.
Common Questions About The Dometic Furnace Reset Switch
What If The Reset Button Is Not Accessible?
Some models enclose the switch behind interior panels. Inaccessible switches may require partial disassembly. If removal of cabinetry or major panels is needed, professional service is recommended.
Can A Reset Switch Be Bypassed?
Bypassing a safety device is dangerous and illegal in many jurisdictions. Never bypass the reset switch as it defeats critical overheat protection and creates fire risk.
How Long Does A Reset Switch Last?
Lifespan varies by usage and environmental conditions. A well-maintained furnace may see the switch last many years; frequent overheating or moisture exposure shortens life. Replace at first sign of unreliability.
Parts And Suppliers
Reliable sources for Dometic furnace reset switches include authorized Dometic dealers, major RV parts suppliers, and reputable online retailers. When ordering, confirm the furnace model number and part number. OEM parts provide the best assurance of fit and safety.
Key Takeaways And Best Practices
For safe, reliable operation of a Dometic furnace, regular maintenance, careful diagnostics when the reset switch trips, and prompt replacement of faulty components are essential. Always follow safety protocols, consult the owner’s manual, and seek professional help for complex electrical or gas-related issues.