Torpedo level
Carbide-tipped masonry bit
Hole saw bits – carbide tipped
Hammer drill
Pliers
Tubing cutter
Propane torch
Wrench
Soldering Essentials: In addition to your propane torch, you’ll need lead-free solder, flux (an acidic paste applied to copper before soldering), a wire brush for cleaning inside copper tubing, and fine-grit sandpaper for polishing the outside of copper tubing before soldering. Keep a damp cloth handy for cleaning freshly soldered joints and a spray bottle filled with water to prevent fires near the work area.
Pro Tip: Don’t be daunted by the many tools listed. Several are included just in case — you can’t know exactly what you’ll need until you can see inside the wall. A small “imp” tubing cutter is especially useful for working in tight spaces. Also, be sure to have a fireproof plumber’s cloth and a bucket of water or small fire extinguisher on hand whenever soldering near framing or other combustible materials.
In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to install an instantaneous water heater.
Why This Location? As explained during a This Old House project, the ideal spot for a tankless water heater is an exterior wall with a nearby gas line. Richard Trethewey notes: “We can bring the gas down into the bottom of the unit and we can exhaust the unit straight through this exterior wall.” Since the unit has a fan to push flue products out, being on an outside wall simplifies venting considerably.
Steps:
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.
Gas Line Sizing Matters: According to This Old House Magazine, for the burner in a tankless heater to perform properly, it has to be hooked up to a gas-supply line that delivers enough volume at sufficient pressure. In many cases, that means the diameter of the supply pipe has to be increased to ¾ inch. If the pressure falls short, the gas company will have to adjust the regulator on the meter.
Pro Tip: When drilling the vent hole through masonry, don’t try to go through in one shot. As demonstrated on a This Old House project, drill halfway through from the inside, then go outside and drill halfway back through. This technique prevents blowing out the brick on the exit side. Also note that by local code, these vents typically have to be at least 3 feet from a gas meter, 2 feet from a fence or wall, and 12 inches above grade.
