Wood stove and insert sweeping, through the liner or with the insert pulled

What you are seeing

Stove and insert owners call us when the stove starts behaving like this, often a few weeks into the heating season.

• Smoke puffs back into the room when you open the stove door to reload.
• The fire is sluggish with the air wide open, and the glass blacks over in a night.
• A tarry smell from the stove on mild days, or black liquid weeping from a connector pipe joint.
• Flakes of black fall into the firebox from above when the stove is cold.
• The insert has never been out of the fireplace, and nobody knows what is behind it.

What we do on a stove sweep visit

A stove sweep works from the appliance up, because the baffle, the combustor and the connector pipe collect as much as the flue does.

1. Cold stove, drop cloths and a sealed firebox

   The stove has to be cold, so no fire the night before. Drop cloths run from the entry to the stove, and the vacuum hose goes into the firebox so air moves toward it while the brush works. On an insert the surround panel comes off first so we can see the connection and the block-off plate.

2. Take out the baffle and check the combustor

   The baffle plate or the ceramic baffle boards lift out from the top of the firebox so the brush can reach the flue collar; we photograph them for cracks and sag and vacuum the secondary air tubes. On a catalytic stove the combustor comes out, gets a soft brush and a light held behind it to show plugged cells.

3. Brush the liner from inside the stove, or from the roof

   With the baffle out, poly rods and a brush sized to the liner go up from the firebox, which keeps the creosote falling toward the vacuum. If the collar or an elbow stops the rods, we go to the roof, take off the cap and sweep down. A masonry flue above a slammer install gets a wire brush and a camera.

4. Clean the connector pipe and the thimble

   Single wall connector pipe comes apart at the joints and gets brushed outside; double wall stays in place and is brushed from the stove end. We check the pipe for rust-through, loose screws and a joint that weeps tar, and we look at the thimble where the pipe passes through the wall for scorched trim.

5. Look over the stove: gaskets, glass, bricks and clearances

   A door gasket that will not grip a strip of paper lets air in and makes the stove run away; cracked firebrick and a sagging baffle can be signs of overfiring. We measure the stove and the connector against the clearances on its label and check the floor protection in front of the door.

6. Photograph, deal with the ash and write it down

   Ash goes in a metal can with a lid, on a noncombustible floor, away from anything that burns; coals in ash can stay alive for days. You get flue photos from before and after, plus the connection, plus a short note on creosote degree, what the look-over found, and whether the insert needs its own liner.

Why an insert without a liner is a liner job, not a sweep

An insert pushed into an open fireplace and vented straight into the old flue, what the trade calls a slammer install, cannot be swept clean and needs a stainless liner run from the collar to the cap.

The insert's exhaust leaves a small collar and spreads into a much larger flue, so it cools, slows and condenses across the smoke shelf and down the back of the insert, where no brush reaches without pulling the unit.

A full liner connected to the collar fixes it: the flue is the right size, it stays warm, and the brush reaches every inch from the firebox. We sweep what we can on the first visit, walk you through the photos, and price the liner as its own job.

Why we pull some inserts and leave others in place

An insert with a liner connected to its collar usually sweeps through the stove with the baffle out; an insert with a short stub liner or none at all has to come out.

Pulling an insert means disconnecting the liner or the stub, lifting a unit that can weigh several hundred pounds onto a hearth protector, cleaning the smoke shelf and the back wall, then setting it back. It adds an hour or more and is priced as its own line.

Oregon stove rules that show up on a sweep visit

Two rules matter to stove owners: DEQ emissions labels, which decide what happens when the house is sold, and county restrictions on burning when the air is bad.

Under Oregon's home-sale removal law an uncertified stove or insert is removed and destroyed when the house sells, unless an exemption applies, and no DEQ or EPA label on the back means uncertified. We photograph the label on every sweep so you have it, and our guide to the home-sale law covers the exemptions and the forms.

Multnomah County can restrict wood burning on poor air days in any month, parts of Washington County do so from November 1 to March 1, and DEQ posts advisories elsewhere; our wood burning rules guide keeps the details. Among the three counties, Clackamas has the largest share of homes heated mainly with wood.

What moves the price of a wood stove or insert sweep

The posted price covers a freestanding stove or a lined insert with one flue, and the items below raise it.

• Pulling and resetting the insert, priced as its own line before we lift anything.
• A slammer install, where the masonry flue above the insert needs a wire brush and a camera run.
• A catalytic combustor that is plugged and needs soaking rather than brushing.
• Top-only access on a steep or wet roof, or a liner with an offset that stops the rods.
• Crusty second-degree buildup that calls for a rotary head; glaze becomes a creosote removal job.

Burning so the next stove sweep is a short one

Burn split, seasoned wood under 20 percent moisture and keep the fire hot, because wet wood and smoldering overnight burns make much of what we brush out of a stove flue.

Portland's airport logs measurable rain roughly 157 days each year, so wood stacked uncovered stays damp. Split it, stack it off the ground under a roof with the sides open, and give it six months or more to get under 20 percent moisture; a moisture meter settles the argument.

Burn hot and bright after each reload until the wood catches, then turn the air down, and skip the all-night smolder with the air shut. Put a carbon monoxide alarm on the floor of the house the stove heats.

When a repair stops making sense

The sweep stops being the answer when the stove is the problem: a firebox warped from overfiring, a baffle burned through twice, or a combustor that no longer lights off after cleaning. A hearth dealer prices the replacement and we sweep whatever goes in.

For an insert in an open flue with no liner, the liner is the fix, and it goes in before the next heating season or the insert stays cold. An uncertified stove in a house about to sell goes out under state law.

Related pages

Services, symptoms, fireplace types and guides that connect to this page.