• This Old House plumbing and heating expert Richard Trethewey shows how to save energy and boost the efficiency of a boiler


    1 Use a ½-inch-diameter bit to bore a hole through the exterior, north house wall and into the basement.
    2 From inside, feed the weather-responsive control's cable through the hole to the outdoors.
    3 Make the wire connections to the rear of the control's base.
    4 Screw the base to the house, then snap on the cover.
    5 At the boiler, use a cable tie to secure the control's temperature sensor to the hot-water pipe leading out of the boiler.
    6 Cover the sensor with foam-rubber pipe insulation.
    7 Mount the outdoor reset control to the side of the boiler by drilling 3/32-inch-diameter pilot holes through the boiler cabinet, and then securing the control with short sheet metal screws.
    8 Hook up the wires at the outdoor reset control, including connecting wires from the outdoor control and to the boiler sensors, and wires that carry voltage to the control and to fire the boiler.
    • 2 to 4 hours, depending on the location and accessibility of the boiler
    • Difficulty: Moderate
      follow the installation instructions carefully and you shouldn't have any trouble
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      Tools List

      • drill
        Drill/driver fitted with ½-inch and 3/32-inch drill bits, used to bore cable hole through house and drill pilot holes in boiler cabinet
      • wire strippers
        Wire stripper, for connecting wires to sensor
      • Phillips screwdriver
        Screwdriver, for driving in sheet metal screws and tightening wire connections

      Shopping List

      1. Weather-responsive control and cable, an electronic device that relays the outdoor temperature to the boiler

      2. Cable ties, used to secure the control's temperature sensor 3. ½-inch sheet metal screws, for securing the control to the boiler

      4. Foam rubber pipe insulation