Furnace Repair in Cloverdale

How a furnace starts, and where the sequence breaks

A modern gas furnace runs a fixed startup order, and every step has to prove itself to the control board before the next one is allowed to happen.

The thermostat closes a low-voltage circuit. The inducer motor spins up and pulls air through the heat exchanger and out the flue. A pressure switch senses that draft and closes, which is the board's proof that exhaust is leaving the building. Only then does the igniter energize. The gas valve opens, the burners light, and a flame sensor sitting in the fire has a few seconds to return a small current confirming combustion is happening. If it does, the blower starts after a built-in delay. If any step fails to prove itself, the board shuts the gas off, retries a set number of times, then locks out.

Nearly every no-heat call here is one of those handshakes failing, so naming the specific step that stalls is most of the diagnosis.

What fails, and what each failure looks like from the hallway

• Hot surface igniter. The most common single failure. A brittle ceramic element cycles hot and cold until it cracks. The inducer runs, no glow appears at the sight window, the burners never light.
• Flame sensor. An oxidation film builds on the rod and the current it returns drops below threshold. The signature is unmistakable: burners light, run four or five seconds, shut off, retry, lock out.
• Blocked flue or stuck pressure switch. The inducer runs and nothing follows. On rural parcels this is often a nest built in a flue that sat unused all summer, which makes it a venting problem before a furnace problem.
• Blower motor or run capacitor. The motor hums without turning, or starts and trips on its own thermal overload. On a shared air handler this kills your cooling too.
• High limit tripping. Heats a few minutes, shuts down, repeats. Almost always restricted airflow rather than a bad switch: a clogged filter, a closed return, or crushed flex duct overheats the cabinet.
• Control board. Relays weld shut, or the board burns because a failing motor drew more current than it was rated to feed. Replacing it without finding that motor guarantees a second visit.
• Cracked heat exchanger. The failure that ends the repair conversation, because it can put combustion products into the air your blower delivers to bedrooms.
• Thermostat and control wiring. Frequently a smart thermostat installed without a common wire, stealing power through the control circuit and confusing the board.

How a real diagnosis runs

A diagnosis worth paying for is a sequence of measurements, not a sequence of guesses.

We confirm the call for heat reaches the board, read the fault history stored there, then watch a full ignition attempt end to end so we see which proof step stalls instead of inferring it. From there the numbers do the talking. We measure manifold gas pressure against the nameplate, temperature rise between return and supply air against the range printed on the unit's own data plate, static pressure across the air handler, and flame signal current at the sensor.

Those readings sort the problem before a part is quoted. Temperature rise above the nameplate range is an airflow problem, and a new limit switch will not touch it. Low flame signal on a clean rod points at gas pressure or burner condition. We finish with a combustion check and a visual inspection of the heat exchanger, because that finding overrides the rest.

Repair or replace, in order

Homeowners want a rule. Here is ours, in order.

Safety. A failed heat exchanger, venting that cannot be made to draft correctly, or combustion readings that cannot be corrected are disqualifying. No repair price makes an unsafe heat exchanger a good idea, and we will not put one back into service.

Parts. Is the failed component still manufactured, and is it a commodity item or a model-specific assembly? Igniters, sensors, capacitors, and most motors cross brands. Integrated boards for discontinued models are a different situation, and on equipment old enough that its board is obsolete, the next failure has no fix at all.

Remaining life. Age against realistic service life, prior repair history, and whether the proposed fix addresses the cause or only the symptom. A board that burned because of a dying blower motor is two repairs, not one.

Clear all three and repair it. Fail the first and the decision is made for you. Fail the second or third and the real question becomes what you put in its place.

Permits, code, and inspection for Cloverdale furnace work

• Who issues the permit. Inside city limits it is the City of Cloverdale Building Division, which takes applications through its online permitting portal. Outside them, including much of the Alexander Valley and the rural parcels around it, the authority is Permit Sonoma.
• Repair versus replacement. Swapping a component inside an existing appliance is generally maintenance. Installing a different appliance, or altering venting, gas piping, or ductwork, is permitted work. Confirm scope with the jurisdiction covering your address.
• Inspection scheduling is a genuine project constraint here. The city's Building Division states that it conducts inspections and plan check reviews Monday through Thursday from 2 to 4 p.m., and that "requests for inspections must be made at least 24 hours in advance to guarantee the inspection." On a small-city calendar, that window shapes when a change-out gets closed out.
• Title 24 energy standards. California's 2025 Building Energy Efficiency Standards took effect January 1, 2026, per the California Energy Commission, and a replacement documents compliance. Read carefully here: that cycle set a single fuel baseline for new single-family construction, with heat pumps prescriptively required for water and space heating alike, and a new-construction baseline does not extend to swapping equipment in an existing home.
• Carbon monoxide alarms. California Health & Safety Code §17926 requires an owner to install a carbon monoxide device "in each existing dwelling unit having a fossil fuel burning heater or appliance, fireplace, or an attached garage," placed consistently with new-construction building standards or the manufacturer's instructions.
• Air district, and this one is specific to Cloverdale. The town sits in the Northern Sonoma County Air Pollution Control District, not the Bay Area district, per Sonoma County's own listing of air quality districts. If a search result told you gas appliances are being outlawed where you live, check which district you are in.

What drives the cost of a furnace repair in Cloverdale

The largest variable is which part failed, and specifically whether it is a commodity item stocked across brands or an assembly built for one model line. Igniters, flame sensors, capacitors, pressure switches, and most inducer motors are the reason a large share of no-heat calls resolve in a single visit. Integrated boards, variable-speed motor modules, and manufacturer-specific gas valves are the group where availability rather than complexity sets the timeline, and on a discontinued model a board sourced from a specialty supplier changes both the schedule and the math on whether repairing makes sense at all.

Access is the next factor, and it splits along local housing stock. Older in-town homes frequently have equipment tucked into a hallway or utility closet with minimal clearance, sometimes sharing it with a water heater, so service clearance, combustion air, and shared venting all have to be respected while working. Valley properties more often have garage or exterior installations with room to move, though longer duct runs and deferred service turn up more often. A crawlspace or attic install is slower than a garage install for identical work.

Whether the fix addresses cause or symptom matters financially even when it does not look that way at the time: a limit switch installed on a furnace that overheats from a restricted return will fail again. Warranty status is worth checking early, since many furnaces carry a multi-year manufacturer parts warranty that registration can extend. It covers the component and not the labor, but on an expensive part it moves the decision.

The state of the incentives

Repairs almost never qualify for a rebate. Incentives attach to equipment replacement, and nearly all current programs target electrification rather than gas, so this is really a conversation about whether a failed furnace is your moment to convert.

Ask any bidder to name and link the program they are quoting.

Sonoma Clean Power is the community choice energy provider here, and its offerings move on their own schedule. Its published water heating terms carry an enhanced heat pump water heater rebate with an end date on it, and once that steps down the rebate is available only to customers on the CARE or FERA bill discount programs. We check what is open when we scope the work.

Where we work in Cloverdale, and what changes by area

We cover downtown Cloverdale, the neighborhoods along the Asti Road corridor, and out into the Alexander Valley and the rural parcels around it.

In town, the older housing stock means interior closet furnaces, tight clearances, duct systems sized around a different set of assumptions, and electrical services never planned around a second 240-volt appliance. Those constraints shape what is practical, and they are why we take readings before recommending equipment.

Out in the valley the lots are larger, equipment more often sits in a garage or exterior closet with room to work, and many parcels are on wells and septic. That last detail matters more than it sounds. This area faces PG&E Public Safety Power Shutoffs, and plenty of homeowners are surprised to learn a gas furnace does nothing during an outage: the board, the inducer, and the blower all run on household electricity, so no power means no heat regardless of how much gas is in the line. On a well, the pump stops at the same moment. As a Certified Generac Generator installer we can plan standby generation alongside the heating work rather than as a separate project. If your property runs on propane instead of natural gas, the furnace also needs the correct orifices and pressure setup for that fuel, worth confirming before equipment is ordered.

How to choose a furnace contractor in Cloverdale

Ask what will be measured. Anyone who reads temperature rise, static pressure, gas pressure, and flame signal is going to find the cause. Anyone quoting a part over the phone is guessing, and you pay for the guess twice.

Ask about license class. Furnace work belongs to a C-20 HVAC contractor. If the job touches the panel or a new circuit, C-10 electrical applies, and gas piping or a shared-closet water heater brings in C-36 plumbing. We hold all three, so a mixed-scope job does not turn into three separate schedules.

Ask what they plan to do about your cooling. Recommending a furnace replacement in this town without one question about the condenser outside is solving half the problem.

On credentials: Ongaro & Sons is Diamond Certified, a Trane Comfort Specialist, a Mitsubishi Diamond Contractor Elite, and holds a BBB A+ Rating. We have been family-run since 1932 and everything dispatches from our Petaluma headquarters. Our full heating and cooling service in Cloverdale covers repair, replacement, ducts, and maintenance.

What North Bay homeowners say

Two reviews from customers who called us about furnace work.

Furnace repair across Cloverdale and Sonoma County

More from Ongaro & Sons nearby: heating and cooling across Sonoma County, every service we offer in Cloverdale, and furnace repair in Windsor just down Highway 101.