• In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to install an instantaneous water heater.

    1 Use template to mark position of vent hole on exterior wall of basement.
    2 Bore center pilot hole for vent using a 3/8-inch-diameter masonry bit.
    3 Cut vent hole through wall using large-diameter masonry hole saw; check installation instructions for exact hole diameter.
    4 Using black iron pipe, run new gas line from gas meter to heater location.
    5 Mount water heater to wall using brackets and bolts provided.
    6 Assemble vent pipe, starting with the elbow at top of heater.
    7 Attach the exterior portion of the vent pipe onto the heater's elbow from outside.
    8 Connect the new gas line to the heater.
    9 Run new water line from the heater using copper tubing.
    10 Connect water line to the home's plumbing system.
    11 Open the valve to purge air from the system; catch expelled water in bucket.
    12 Test the heater to ensure the burner ignites.
    • Difficulty: Hard
      Requires advanced plumbing skills

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      Video Directory

      Selected Topic/Section

      Tools List

      • torpedo level
        Torpedo level
        to level template when marking wall
      • marking knife
        Carbide-tipped masonry bit
        to bore pilot hole through masonry wall
      • 3/16 masonry bit
        Carbide-tipped masonry hole saw
        for cutting vent hole through masonry wall
      • masonry hoe
      • hammer drill
      • needlenose pliers
        Tubing cutter
        for cutting copper tubing
      • tubing cutter
        Propane torch
        for soldering together copper tubing
      • propane torch

      Shopping List

      1. Instantaneous water heater

      2. Copper tubing and assorted fittings, for running new water-supply line

      3. Iron pipe and assorted fittings, for running new gas line

      4. Lead-free solder

      5. Flux, applied to copper joints prior to soldering

      6. Emery cloth, for cleaning copper tubing prior to soldering

      7. Canvas drop cloth, for protecting floor

      8. Bucket, to catch water when purging heater of trapped air