North Sound RV Repair provides on-site RV furnace repair throughout Everett, Marysville, Mukilteo, Lynnwood, and all of Snohomish County. A furnace failure in western Washington — where overnight temps drop into the 30s even in late spring — is a priority call. We diagnose and repair Atwood (Dometic) and Suburban RV furnaces at your location, with most repairs completed in a single visit.
The most common furnace call we receive happens in September and October — when RV owners dust off a rig stored since spring and discover it won't fire. Almost always: a fouled sail switch, a corroded thermocouple, or a spider web in the combustion air intake. All preventable. All fixable on-site in a single visit.
We prioritize furnace calls in cold weather. Most repairs are completed in a single visit with parts carried on the truck.
Call for a same-day estimateThe control board sequences the blower, igniter, and gas valve in the correct order. A failed board results in a furnace that clicks and tries to ignite but won't fire, or one that starts, runs briefly, and shuts down. We test the board's input and output signals before replacing it — a board that appears failed is sometimes responding to a failed sensor or wiring issue that would cause the replacement to fail as well.
The sail switch confirms the blower motor is producing sufficient airflow before allowing the gas valve to open. A sail switch that fails to close — due to a bent sail, debris obstruction, or worn contacts — results in a furnace that runs the blower but won't light. This is one of the most common furnace failures on rigs that have been stored unused for a season. We carry sail switches for all major Atwood and Suburban models.
The thermocouple (on older pilot-lit furnaces) or flame sensor (on DSI furnaces) confirms the burner has lit before the gas valve stays open. A failed thermocouple causes the furnace to light and then immediately shut off — typically within 2–3 seconds. Thermocouple replacement is one of the most common and least expensive furnace repairs we perform.
The blower motor pulls combustion air into the burner and pushes heated air through your RV's duct system. A seized or failing blower results in a furnace that won't start at all (the sail switch won't close without airflow) or one that produces heat at the furnace but doesn't distribute it through the ducts. We test motor amperage draw before replacement — a motor drawing excessive current is failing even if it's still running.
A furnace that works fine at one location but not another often has a propane supply issue rather than a furnace problem. We test propane pressure at the furnace inlet, check regulator output, and inspect the supply line for restrictions or leaks. We also check for freeze-off in the regulator — a common cold-weather issue commonly mistaken for furnace failure.
Propane system issues are common in stored rigs — especially if the OPD valve on the tank was fully closed during storage, which causes a low-flow condition when first reopened.
The gas valve controls propane flow to the burner. A valve that fails open is a safety emergency — the furnace will smell of gas and should not be used until repaired. A valve that fails closed results in a furnace that goes through the ignition sequence (blower runs, igniter fires) but won't produce heat. Gas valve replacement requires pressure testing before and after to confirm the repair is correct.
A thermostat that's lost calibration, has a failed internal switch, or has corroded terminals can prevent the furnace from calling for heat even when the furnace itself is functional. A bad thermostat wire — common in rigs where wiring has been pinched or chewed by rodents during storage — is a cheap fix that looks like a furnace problem. We test thermostat output voltage and wiring before condemning the furnace.
An RV furnace that sat unused through a storage season accumulates spider webs (a surprisingly common ignition obstruction), dust in the combustion air intake, and corrosion on the igniter and flame sensor. An annual cleaning and service — checking the igniter gap, cleaning the burner and sail switch, testing the thermocouple, and verifying gas pressure — extends furnace life and prevents the mid-trip failure that happens when a marginally operating furnace is pushed hard on the first cold night of the season.
We service both major RV furnace brands on-site. Here's a quick reference for the common failure patterns we see on each.
| Feature | Atwood / Dometic | Suburban |
|---|---|---|
| Common failure points | Sail switch, circuit board, thermocouple | Sail switch, gas valve, limit switch |
| Ignition type | Direct spark ignition (DSI) | Direct spark ignition (DSI) |
| BTU range (common) | 16,000–30,000 BTU | 16,000–40,000 BTU |
| Parts availability | Good — widely stocked | Good — widely stocked |
| We service on-site? | Yes | Yes |
Clicking that doesn't result in ignition usually means one of three things: no propane reaching the burner (check that the tank isn't empty and the valve is fully open), a failed igniter that isn't producing a strong enough spark, or a gas valve that isn't opening. If you can smell propane during the ignition attempt but the furnace still won't light, the igniter is the likely culprit. If you smell nothing, start with propane supply. Call us — we'll walk you through it on the phone first.
A furnace that lights and shuts off within 2–4 seconds almost always has a failed thermocouple or flame sensor. The control board lights the burner, the thermocouple doesn't confirm the flame in time, and the board shuts the gas valve as a safety measure. Thermocouple replacement is one of our most common furnace repairs and is usually completed in under an hour on-site.
Most furnace repairs run $150–$400. Simple fixes — a thermocouple, a sail switch, or a propane supply issue — are at the lower end. Control board replacement is typically $250–$450 depending on the part. We give you a written estimate before any work begins and don't proceed without your approval.
Yes. We make furnace service calls at storage facilities throughout Snohomish County. The most common scenario is a pre-trip furnace check or repair at a Smokey Point storage lot in Marysville before a fall or winter camping trip. As long as you have propane in the tank and we can access the furnace compartment, we can diagnose and repair it on-site.
A furnace that lights correctly but shuts off after a few minutes is generally safe to use — the control board is doing its job protecting against a failed sensor. A furnace that smells of propane during operation or produces incomplete combustion should not be used until repaired. If you have a CO detector alarming near the furnace, turn it off and call us immediately.
If the furnace fires and runs but heat isn't reaching the living space, the issue is usually in the ducting or the blower — not the burner. Collapsed duct sections, closed or blocked registers, and a failing blower that's producing heat at the furnace but not enough airflow to move it are all common causes. We diagnose duct and airflow issues as part of any furnace service call.
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We come to your home, storage lot, or campground — anywhere in Everett, Marysville, Mukilteo, Lynnwood, and surrounding Snohomish County.
Call (425) 645-6388