Special handling requirements for CWKs (Ceramic Chimney Blocks)

1. Do not transport the blocks loosely laid – if no standard packaging can be used for a small number of units, use a belt or a foil to wrap up them. You can also place a soft material between the single units to prevent damage during the transportation (microcracks, damaged tongue or socket).
2. Before inserting a CWK to the chimney, tap it –a damaged CWK generates a hollow crunching sound (invisible microcracks) instead of a bell-like one. Do not use improper CWKs.
3. In order to join the CWKs use the Rudokit NT 1350 or Rudomal KV cements – products of P-D Refractories CZ S.A. Velke Opatovice (or other cements approved for chimney units
4. To compensate for thermal expansion of the ceramic units allow a gap between the chimney walls, its top and the ceramic units (the higher the chimney and the temperature of flue gases, the bigger change of the ceramic unit length)
   • The top of the last KZ chamotte pipe shall be at least 10mm below the coping slab
   • The gap between the pipe and the coping slab shall be protected from water by an elastic sealant (acryl, silicon)
   • Install a mineral wool between the entry of the flue pipe (a KS fitting) into the chimney (including the plaster layer)
   • Use a heat-resisting ceramic cord between the connection pipe of the oven and the KS fitting, the expansion gap should be of 5 to 10 mm
   • The connection pipe of the stove should be installed axially to the KS fitting
   • The connection pipe of the stove should be inserted into the KS fitting to a maximum depth of 60 mm
   • The gap between the chimney, CWK and the setting (if no insulation was used) shall be min. 10 mm
5. To inform the user that a direct exposure of the CWK wall to fire (e.g. when the construction site is heated before the full installation is not completed, in case of stove overheating or when an incorrect fireplace is used – without a register plate, or in case of a wood-gas stove, which does not enable draught adjustment in the first phase of heating) may result in cracks
   

• Provisional heating sources should be located in a furthest possible distance from the chimney, a long chimney connection pipe or a pipe with a lot of elbows shall be used to prevent fire gets into the chimney)
• Local heating systems should be operated at optimum power
• Use a proper furnace 
• Buy a proper wood-gas stove – it should be necessarily adjustable at fire-up