Supra USKO Wood Burning Stove
Installation and User Manual
Introduction
Congratulations on choosing the Supra USKO wood-burning stove. This appliance has been carefully designed to provide optimal performance and safety. For the best results and to ensure correct installation, it is recommended to use a specialist from the Supra brand. Please read this manual carefully before first use and keep it along with the warranty for future reference. Failure to comply with these instructions will render the installer fully responsible.
Important Assembly Information
Proper chimney draught (measured in Pascals, Pa) is crucial for the stove's operation. The USKO stove is designed for a draught of 12 Pa. Excessive draught (over 20 Pa) can lead to increased wood consumption, rapid burning, premature deterioration of the appliance, and voided warranty. If your chimney draught is too high, consult a professional to install a draught regulator or adaptor.
1. Technical Specifications
| Feature | USKO |
|---|---|
| Stove category | Swivel Stove / Orientable |
| Rated heat output | 8.7 kW |
| Operating mode | Intermittent / Only with the door closed |
| Connection type | Horizontal or vertical |
| Mean flue gas temperature | 301 °C |
| Efficiency | 77% |
| Seasonal efficiency | 67% |
| CO concentration (13% O2) | 0.08% |
| CO2 concentration (13% O2) | 9.4% |
| Dust concentration (13% O2) | 40 mg/Nm³ |
| VOC | 55 mg/Nm³ |
| NOX | 130 mg/Nm³ |
| Fuel | Wood |
| Log size | 50 cm |
| Nominal load per hour approx. | 2.86 kg |
| Refuelling interval | 45 m. |
| Prohibited fuels | All the rest, including coal and its derivatives |
| Approx. flue gas mass flow | 8.92 g/s |
| Flue pipe nominal diameter | 150 mm |
| Characteristics of the flue pipe | |
| Minimum dimensions of the chimney terminal | 20 x 20 cm |
| Ø min. flue lining or insulated metal duct | 150 mm |
| Minimum height of the pipe above the appliance | 4 m |
| Ventilation of the room | 1.2 dm² |
| Draught (10 Pa = 1 mm CE) | |
| Nominal efficiency | 12 Pa ± 2 Pa |
| Performance in slumber mode (min. permitted) | 6 Pa ± 1 Pa |
| Max. permitted | 20 Pa |
| Nameplate | On the rear of the appliance |
| Accessories supplied | Insulating glove |
| Option available | - |
(1) Rated power in operation with the door closed, wood or lignite fuel, according to tests performed under standard EN 13240. (2) DTU 24.1, DTU 24.2, NF EN 13240 standards apply.
Warnings
This appliance is designed solely for burning wood. It must not be used as an incinerator or for burning liquid fuels, coal, or their derivatives. Always comply with local, national, and European regulations during installation and use. The stove becomes hot during operation, especially the glass window, and remains hot for a long time after the flames have died down. Take precautions to avoid contact, particularly with children. Ensure the power supply is disconnected before accessing electrical connection devices. Installation must conform to applicable standards, and professional installation is recommended. Follow all instructions in this manual carefully and keep it in a safe place. The manufacturer's liability is limited to supplying the appliance and is not responsible for non-compliance with these instructions. Prohibited actions include placing flammable materials near the appliance, installing heat recovery systems, using fuels other than natural wood or lignite, and making unauthorized modifications. The person performing the installation is fully liable for any failure to comply with these instructions. Public installations are subject to municipal health regulations. The manufacturer reserves the right to modify models and dimensions without prior notice.
2. Installation
Definition
The Supra USKO is a wood-burning stove designed for wall installation and can be moved without additional work. It connects to the flue pipe using stainless steel or vitreous enamel pipes conforming to NFD 35-302, and must be connected to an individual flue pipe.
Safety Clearances
Maintain specified safety clearances between the appliance and walls. If the wall is non-combustible, these clearances may not apply. A minimum clearance of 2 meters is required between the glass and any wall or flammable material, regardless of stove orientation.
Preparation of the Stove
Unpack the appliance by removing securing screws. Install the stove on a floor with adequate load-bearing capacity. If the floor is insufficient, reinforce it, for example, with a load distribution plate. Position the stove in its final location and ensure it is level. For easier maintenance, tiling the loading area is recommended.
Mounting the Baffle Plate
The cast iron smoke deflector is crucial for performance, aiding soot collection during sweeping. It is pre-installed upon delivery. Familiarize yourself with its mounting and removal by assembling and disassembling it several times before first use.
Changing from a Top to Rear Outlet
The flue collar (Ø 150 mm) is initially mounted on the top outlet. It can be relocated to the rear outlet depending on your flue type. To reverse the collar: unscrew the two screws on the flue collar, release the clips on the rear plate, loosen the rear stop, screw the flue collar onto the rear of the appliance, and then re-screw the stop onto the top of the appliance.
Connecting the Flue Pipe
Connect the flue pipe carefully in accordance with DTU 24.1. Connection to a shared flue system is prohibited. If an existing flue is used, it must be cleaned and inspected by a qualified professional for suitability (stability, airtightness, material compatibility, diameter). If the flue is incompatible, contact a specialist for repairs.
Connecting Pipes
Use T450 enamelled or 316 stainless steel pipes, available from your stockist, without reducing their length. The connection must be made in the room where the appliance is installed. Ensure access for chimney sweeping and cleaning. The pipe must not protrude into the flue and connections must be removable and airtight. Maintain a minimum distance of 3 times the pipe diameter between the connecting pipe and the wall. Avoid long horizontal sections; if unavoidable, ensure a 5 cm per meter upward slope.
Combustion Air Connection
Outdoor air intake not connected: If an external air intake connection is not possible, an additional fresh air intake facing prevailing winds is necessary for proper combustion, especially in well-insulated homes or those with mechanical ventilation (V.M.C.). This intake must have a minimum free opening of 1 dm². Do not operate the stove if a smoke extractor hood is in use. If the dwelling lacks a sweeping ventilation system (per March 1982 decree), the air inlet must be unobstructed.
Outdoor air intake connected: A Ø 100 mm external connection at the rear of the stove draws combustion air from outside, improving efficiency and reducing discomfort from cold air. If this intake does not supply all necessary combustion air, an additional 50 cm² air inlet is required.
Principles for the supply of combustion air:
- Directly through the wall.
- Through a duct leading to a crawl space; the ventilation grid section (cm²) must be 5 times the crawl space surface area (m²).
- Through a buried duct (max. one 90° elbow).
Maximum duct length: 6 m for Ø 80 mm, 8 m for Ø 100 mm. Connect the collar externally with a clamp (not supplied) and an aluminium flexible tube (not supplied). Re-attach the rear plate if necessary. Ensure the air inlet is unobstructed. The external duct should face prevailing winds. Install a protective grid at the duct opening to prevent obstructions, with a free cross-section equal to the duct's and mesh size greater than 3 mm.
3. Use
Take Note
This wood-burning stove is designed for use with the door closed at all times, except for refuelling. To prevent burns, do not touch the appliance and use the provided glove to operate controls. Maintain a safety clearance of 2 meters from the glass to any material that could be damaged by heat (furniture, wallpaper, woodwork, etc.).
Fuel
Wood
Burn only air-dried logs (2-3 years storage, sheltered and ventilated) with 15-20% maximum humidity. Hardwoods (birch, hornbeam, beech) are preferred. Avoid softwoods (lime, chestnut, willow, poplar). Permanent use of softwoods (pine, fir) and treated wood waste (railway sleepers, etc.) or household scraps is strictly forbidden. Never use small wood, boxes, wood chips, or vine shoots, as they can cause sudden overheating.
Lignite
Lignite briquettes can be used alone or with wood for slower burning. Place them in a single layer on embers, covering only the grate surface.
Caution: Coal or its derivatives are strictly prohibited, even occasionally. This appliance must not be used for burning domestic waste.
Controls
Combustion air control
The air control regulates combustion air flow for precise fire management.
| Control | Primary Air Damper (1) | Secondary Air Damper (2) |
|---|---|---|
| Lighting the fire | Open / Draught | Open / Draught |
| Nominal efficiency | 1/2 | 1/2 |
| Performance in slumber mode | 1/2 | Closed/Pressed |
Damper 1 controls heat output. Damper 2 is used only for initial heating; close it once the stove is hot. Keeping Damper 2 open when the stove is hot can cause overheating and damage internal parts.
Door handle
To open/close the door: use your hands when the appliance is cold, and an insulating glove when it is hot.
Lighting the Fire for the First Time
Remove all self-adhesive labels (except the nameplate) and blocking materials. Ensure the ash tray is empty. Start with a small fire and gradually increase the load to allow materials to expand and stabilize. Initial use may produce fumes and odors from the paint, which will dissipate. Ventilate the room during the first few uses. Check the draught according to the technical specifications.
Service: Lighting the Fire
For lighting, use the top-down method to pre-heat the flue and prevent blockages or downdrafts. Procedure: Pull air control to maximum, place 2 logs on the grate, stack kindling wood like a tower on the logs, place 1-2 fire-lighter cubes on the kindling and light them, close the door. For more information, watch the Supra YouTube video: https://www.youtube.com/watch?v=ebOr4vMj2Jo. Caution: Never use petrol, alcohol, or fuel oil.
Reloading
Reload when a good bed of embers remains and flames have disappeared. Open the loading door slowly to prevent smoke escape or ember fall. Close the door after reloading.
Nominal efficiency
Adjust controls per the table. Fire intensity depends on fuel quantity. Proper appliance function relies on adequate air supply.
Nominal Loading
For optimal operation, load 2 small logs, placing them towards the back of the appliance to prevent embers from falling out.
Performance in slumber mode
Adjust controls per the table. Avoid prolonged operation in slumber mode, as insufficient flue gas temperature can lead to condensation, increasing soot and dirt in the chimney and appliance.
In the Event of an Incident
In case of a fire (chimney fire, room fire, etc.), quickly close the loading door and all stove controls. Do not pour water into the firebox. Call the fire brigade.
4. Maintenance - Recommendations
Ash Removal
Ash can be removed while the stove is operating. Regularly empty the removable ash tray. Excessive ash hinders airflow under the grate, potentially causing deformation and affecting combustion. Replace the ash tray after emptying.
Cleaning the Front and Sides
Clean the stove with a soft, dry cloth only. Do not use water, solvents, or abrasive products.
Cleaning the Glass Window
Clean the glass when cold, using a damp cloth with wood ash. The air wash system helps keep the glass clean, though slight darkening may occur during normal operation. The air wash is less effective in slumber mode.
Soot Removal
Legislation requires two chimney sweeps per year (one during the heating season) using mechanical means. Keep proof of service. Remove the second deflector during sweeping.
Annual Maintenance
After each heating season, thoroughly clean the stove and check all moving parts, seals, and parts in contact with flames for proper operation and condition.
5. After-Sales Service
The appliance has wear parts that require annual checks. Your dealer can supply necessary spare parts. When requesting information or parts, provide the part number and serial number found on the appliance's nameplate. Use only manufacturer-recommended spare parts.
