Superior WCT6940 EPA Certified Traditional Wood Burning Fireplace

Superior WCT6940 EPA Certified Traditional Wood Burning Fireplace

The Superior WCT6940WS is the largest of Superior's EPA-certified wood-burning fireplaces, and the only catalytic one. Its insulated 4.0 cu ft firebox takes logs up to 30" long behind a pair of steel doors with 31" x 15" of ceramic glass, lined with textured stacked refractory and fitted with cast iron log retainers. Smoke passes through a catalytic combustor that burns it off at lower temperatures, which cuts emissions to 1.3 grams an hour and leaves less creosote, and a 350 CFM heat-activated blower sends the heat into the room.

With the air wide open it puts out up to 80,000 Btu an hour; turned down, it holds a fire for six to eight hours. A bypass lever opens a direct path to the chimney for lighting and reloading, then closes to send the smoke back through the combustor. It is approved in Washington State. The WCT6940-FAC-BLK black facade and the WCT6940-DOOR-BLK black doors are required and ordered separately, and the outside air kit comes with it.

It vents through Superior's 7" Snap-Pak stainless chimney in the US, at least 12 feet above the fireplace. It has to sit on a non-combustible base and is not approved for manufactured homes. For a non-catalytic fireplace with a 2.19 cu ft firebox, see the WCT6920WSS or the WCT4920WSS; the WRT3920-B has a clean face with its door built in.

Key Features

• EPA certified to the 2020 standard at 1.3 grams of particulate an hour, and approved in Washington State
• Catalytic combustor with a bypass for lighting and reloading
• Up to 80,000 Btu an hour; heats up to about 2,500 sq ft
• Insulated 4.0 cu ft firebox for logs up to 30"
• Textured stacked refractory panels with an integrated ash lip and decorative cast iron log retainers
• Pair of steel doors with cool-touch handles and 31" x 15" of ceramic glass (doors ordered separately)
• Air wash that keeps the glass clean
• Heat-activated 350 CFM blower with a variable speed wall control
• Insulated outside air kit included, as required
• Six to eight hour burns on a low setting
• Optional forced air kit for up to three more rooms
• High-temperature paint finish
• Uses Superior's 7" Snap-Pak stainless chimney in the US
• 20 year limited warranty on the fireplace body and firebox; 3 years on the combustor

What's Included

• Fireplace with textured stacked refractory panels and cast iron log retainers
• Catalytic combustor, bypass and catalyst temperature gauge
• 350 CFM heat-activated blower (UZY5)
• Variable speed wall control (VRUW)
• Outside air kit: 4" insulated duct that stretches up to 10 feet and the coupler that connects it to the fireplace
• Safety metal strip for the hearth extension
• Installation and operation manual, with the combustor warranty

What to Order With It

Required – Facade:

• Black Facade for WCT6940 (WCT6940-FAC-BLK)

Required – Doors:

• Black Doors for WCT6940 (WCT6940-DOOR-BLK), a pair

Required – Chimney (US):

• 7" Snap-Pak Stainless Steel Chimney Length, 6" to 48" (7SPS), enough to reach the minimum height
• 7" Snap-Pak Round Cap with Spark Arrester (7SPC), required on every chimney

As your chimney run needs:

• 7" Snap-Pak 15° Elbow, 2-pack (7SPSE15-2) or 7" Snap-Pak 30° Elbow, 2-pack (7SPE30-2), for an offset (two offsets at most, no more than 30° from vertical)
• 7" Snap-Pak Firestop Spacer (7SPFS), at every ceiling the chimney passes through
• 7" Snap-Pak Insulation Shield (7SPIS), where the chimney runs through an attic that isn't enclosed
• 7" Snap-Pak Flat Flashing (7SPFF), 7" Snap-Pak 2/12-5/12 Flashing (7SPF5) or 7" Snap-Pak 6/12-10/12 Flashing (7SPF10), to match the roof pitch
• 7" Snap-Pak Storm Collar (7SPSC)
• 7" Snap-Pak Adjustable Support (7SPAS); every chimney needs at least one support
• 7" Snap-Pak Support Band (7SPSB), required at the upper elbow of each offset and used with guy wires above the roof
• 7" Snap-Pak Roof Brace (7SPRB), for a chimney more than 4 feet above the roof
• 7" Snap-Pak Non-Insulated Wall Firestop (7SPWF) and 7" Snap-Pak Wall Band (7SPWB), for a chimney that runs out through a wall and up the outside (bands every 8 feet)

Optional:

• Forced Air Kit, Starter Kit for Wall or Floor Installations (BISFWK-1), with a 250 CFM blower, speed control, thermo-disc and backdraft damper
• Flex 5" I.D. x 15' long (5FLEX15) or Flex 5" I.D. x 25' long (5FLEX25), duct for the forced air kit
• Heating/Cooling Thermostat, 120 volt (HCTW), to run the forced air blower automatically

Specifications

Superior designs its EPA fireplaces as supplemental heat for the area around them, not as a home's only heat source. The emissions are from Superior's EPA testing; the heating area is Superior's estimate.

Dimensions and Framing

Fireplace dimensions

Framing

The framing dimensions assume 1/2" drywall at the face; adjust them for other sheathing or finish thicknesses. Frame with 2x3 or larger lumber, with studs running floor to ceiling at the sides and headers only where they carry the facing and mantel. Nothing combustible can go in the space directly above the fireplace, up to 80" from its base, except those framing members, and the fireplace can't touch insulation: cover insulation around it with drywall. Four floor nailing flanges, two on each side, fasten it down. Install it square and plumb, shimmed as needed, so the doors line up.

Installation Requirements

• Base and hearth extension: the fireplace must sit on a non-combustible surface at least 1/2" thick. In front, build a non-combustible hearth extension 1" thick, such as cement board under tile or marble, reaching at least 24" out and 6" past each side of the door opening. Half the supplied safety metal strip goes under the front of the fireplace and half under the hearth, and the gap is sealed with non-combustible material such as sand-cement grout. A raised fireplace needs field-made Z-shaped metal strips across its full width and the same size hearth.
• Clearances: 0" to the non-combustible base and at the side and back standoffs, a side wall at least 24" from the edge of the doors, a ceiling at least 6'8" above the base of the fireplace, and 2" around the chimney. Don't fill the space above the fireplace with anything except the wood framing. Keep furniture and other combustibles 48" from the front.
• Mantel: at least 56" above the base of the fireplace and no more than 12" deep.
• Facing: drywall and other combustible materials have to finish flush with the fireplace and can't overlap its steel face. Brick, stone and tile can overlap the face. Whatever covers the face, the facade must stay removable for service.
• Outside air: the outside air kit is mandatory and comes with the fireplace. Run its 4" insulated duct no more than 20 feet (5" duct for up to 30 feet, 6" for up to 40), with the intake no more than 10 feet above the base of the fireplace. It has to draw from outdoors, never from an attic, basement or garage, in a spot where snow, wind, car exhaust, gas meters and other vents won't interfere. Leave 8" beside the fireplace for the duct when framing.
• Electrical: the blower needs a 3-wire, 120 VAC, 60 Hz unswitched supply to the junction box at the lower right corner of the fireplace, with the included speed control wired in line, installed by a qualified electrician before the face is finished.
• Chimney: in the US, use only Superior's (IHP) 7" Snap-Pak stainless chimney; in Canada, use 7" Security Chimneys ASHT or S2100, or DuraVent DuraTech Canada. The chimney can't vent any other appliance. If possible, run it inside the house: an outside chimney in a place that stays below 0°F draws poorly and builds up more creosote.
• Chimney height: at least 12 feet above the fireplace, or 15 feet with offsets, plus 18" for every 2,000 feet of elevation. The cap has to be at least 3 feet above where the chimney leaves the roof and 2 feet higher than any wall, roof or building within 10 feet, and a rain cap is required.
• Chimney run: two offsets at most (four elbows), no more than 30° from vertical, and the pipe has to run straight up where it passes through a floor or ceiling. Every chimney needs at least one support; the fireplace itself can carry only 9 feet of chimney. A chimney more than 4 feet above the roof needs a roof brace or a support band with guy wires.
• Clearances around the chimney: frame square openings that leave 2" of air space all around the pipe, never filled with insulation, with a firestop spacer at every ceiling and an insulation shield in an open attic. Enclose any part that passes through a floor people use or another accessible space.
• Masonry chimney: it can connect to an existing or new masonry chimney with a stainless steel liner rated to 2,100°F (UL 1777 in the US), after a chimney sweep inspects and cleans the chimney.
• Draft: too much draft overheats the fireplace and can damage the catalytic combustor, and too little lets smoke into the room and plugs the chimney or the catalyst.
• Manufactured homes: this model is not approved for them.
• Cold climates: where it drops below 32°F, seal every gap around the fireplace with non-combustible material and wrap the outside air duct in non-combustible insulation to keep condensation down.
• Gas logs and inserts: don't install gas logs (it hasn't been tested with unvented gas logs), a fireplace insert or any other product IHP hasn't specified for it.
• Smoke and CO detectors: Superior recommends a smoke detector, ideally in a hallway next to the room, and a carbon monoxide monitor, or whatever your local code requires.
• Installation: check local codes and permits before you start, and have a qualified installer follow the installation manual.

Frequently Asked Questions

What does the catalytic combustor do?
Smoke from the fire passes through it, and the catalyst burns off the unburned gases at lower temperatures than a fire alone would, so less smoke leaves the chimney, less creosote builds up and more heat stays in the house. It works once the gases entering it are above about 400°F and doesn't have to glow to be working. Never run the fireplace without it, and never let it overheat: a glowing top of the firebox, seen through the top of the facade, means the fire is too hot.

How do I light and reload it?
Pull the bypass control out to open it and open the air control, light paper and kindling, and add cord wood once the kindling is burning well. After 15 to 30 minutes, when the gauge behind the facade grille (lower right) reads in the active range, push the bypass in to close it, then set the air control, which sits under the doors on the left. To reload, open the bypass and air fully, crack the doors about 1" for five seconds, load two or three pieces spaced 1" to 2" apart as far back as they go, close the doors and close the bypass. Turn the blower off while reloading and wait 15 to 30 minutes before turning it back on.

How much heat does it put out?
Up to 80,000 Btu an hour with the air control wide open, though it then needs wood every hour or two. Superior recommends a medium setting: three medium pieces on a bed of coals give about 35,000 Btu an hour and last three to four hours. Turned down after the fireplace is hot, it burns six to eight hours. Superior puts its heating area at up to about 2,500 sq ft. It is built as supplemental heat, so keep another heat source in the house.

What chimney does it need?
In the US, Superior's 7" Snap-Pak chimney: 430 stainless steel inside and out, 1-1/2" of ceramic fiber insulation, 10" outside diameter and 2" clearance to combustibles, listed to UL 103HT. It must rise at least 12 feet above the fireplace (15 with offsets) and needs the round cap. In Canada it takes 7" Security Chimneys ASHT or S2100, or DuraVent DuraTech Canada.

Can it heat other rooms?
Yes, with the optional forced air kit: a 250 CFM blower pushes heat through 5" duct to as many as three rooms, including rooms on a lower floor, up to 50 feet away, and the HCTW thermostat can run it automatically. The forced air kit was not part of the fireplace's EPA emissions testing, so a fireplace installed with it can't be sold as EPA certified.

Can I burn gas logs in it?
No. It's made for wood only, and IHP hasn't tested it with unvented gas logs. Don't put a gas log set, a fireplace insert or any other product IHP hasn't specified into it; doing so voids the certification and the warranty.

What should I burn?
Only dry, seasoned natural wood, below 20% moisture (a firewood moisture meter helps); split wood dried under cover for about a year usually gets there, and hardwoods burn longer than softwoods. Never burn treated wood, plywood or particleboard, driftwood, coal, charcoal, cardboard, trash or Christmas tree branches, and never start or freshen a fire with gasoline, kerosene or lighter fluid. Fire starters made of paper, sawdust or wax are fine. Wet wood smolders, coats the glass and chimney with creosote and lowers the heat you get. Softwoods need 6 to 18 months of seasoning and hardwoods 12 to 24; split logs more than 5" across. Treated wood, coal, plastic, trash, sulfur and oil can also damage the catalyst.

What upkeep does it need?
The first five or six fires should be small and short, 30 to 60 minutes, to cure the refractory; the paint may smell and smoke a little at first, so keep the room well ventilated. Have the fireplace inspected at least once a year by a qualified technician, and have the chimney cleaned before creosote builds up past 1/16". Remove ashes when they reach 3 to 4" deep, leaving about 1" on the floor of the firebox, and only once they are cold (24 to 48 hours after the fire is out), into a metal container with a tight lid. Look at the catalytic combustor at least three times a heating season and clean it once a year, usually when the chimney is swept: soak it for about 30 minutes in a boiling 50/50 mix of white vinegar and distilled water, rinse it in distilled water and let it dry completely. Never use water, compressed air or sharp tools on it. It should last at least 10,000 hours.

How do I keep the glass clean?
The air wash keeps it clear when the fire burns hot with dry wood; long low burns with the air shut down will dirty it. Clean it with a cleaner made for creosote, never abrasives, steel wool or oven cleaner, and keep the cleaner off the door gasket and the painted face. Replace cracked glass only with Superior's 5 mm ceramic glass, and don't run the fireplace until it's fixed.

Warranty

Superior's 20 Year Limited Warranty covers the WCT6940WS against defects in materials and workmanship:

• Fireplace body and firebox: 20 years
• Ceramic glass: 20 years, against thermal breakage only
• Refractory: 2 years, repair or replacement (hairline cracks excluded)
• Removable air tubes: 7 years
• Other air tubes, baffles and brick retainers: 1 year
• Cast iron parts, gaskets and electrical parts such as the blower: 1 year
• Catalytic combustor: its own 3 year limited warranty
• Parts not listed: 90 days
• Labor: paid at IHP rates for the covered part's warranty period, up to five years

Vent components, trim, paint and applied stains are not covered, and neither is damage from overfiring or from burning anything other than dry, seasoned wood. Using chimney parts other than those named in the installation manual voids the warranty. The warranty is for the original owner of a fireplace installed in the US or Canada. Full terms are in the warranty certificate.

Documents and Downloads

• Installation and Operation Manual
• Specification Sheet
• Brochure
• Snap-Pak Chimney Smart Sheet
• Warranty Certificate