• In this video, This Old House plumbing and heating expert Richard Trethewey shows how to split an existing heating system into separate zones.

    1. Cut temporary hole in furnace duct and attach a take-off fitting.
    2. Attach one end of the flex-tube to the take-off and the other end to the suction fan.
    3. Remove register and seal duct with a foam-rubber block placed inside a plastic trash bag. Repeat for all other heating ducts in the house.
    4. Turn on suction fan to create reverse pressure throughout the ductwork.
    5. Make a parachute from a plastic shopping bag and attach it to a fishing line; send the parachute down one of the ducts.
    6. At furnace, disconnect the flex-tube and pull out the parachute.
    7. Remove the fishing line from the parachute and attach it to a length of pneumatic tubing.
    8. Use a fishing rod to pull the pneumatic tubing from the furnace, through the ductwork and into the register.
    9. At the register, disconnect the fishing line from the pneumatic tubing. Then wrap the pneumatic tubing around the foam block and push it back into the duct. Repeat for all other registers.
    10. Connect the end of the pneumatic tubing to the rear of a damper.
    11. Attach perforated metal strap to side of damper. Secure damper in place by driving two sheet-metal screws through the strap and into the duct.
    12. At the furnace, connect the individual lengths the pneumatic tubing to the manifold.
    13. Connect manifold to air-pump power supply.
    14. Install an electronic touch-pad control panel in kitchen, entrance hall or main living area.
    • Difficulty: Hard
      this is a job for an experienced, professional HVAC contractor

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      Video Directory

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      Tools List

      • metal cutting snips
        Tin snips, used to cut hole in furnace duct
      • drill
        Drill/driver, used to drive screws
      • fishing rod
        Modified fishing rod, for pulling tubing through ductwork
      • suction fan
        Suction fan, used to depressurize the ductwork

      Shopping List

      Take-off fitting, used to attach flex-tube to ductwork

      Flex-tube, used to connect suction fan to take-off fitting

      Pneumatic damper, used to open and close heat ducts

      Pneumatic tubing, used to operate the dampers

      Foam rubber and plastic bag, for sealing up ducts

      Plastic shopping bag, used to form a line-pulling parachute Perforated metal strap, for attaching dampers to the inside of the ducts

      Sheet-metal screws, used to secure metal strap to duct

      Manifold, acts as distribution point for tubing

      Air-pump power supply, inflates and deflates tubing to control zones

      Touch-pad control panel, used to regulate heat to various zones