How to install an instantaneous water heater

Watch this video from This Old House to learn how to install an instantaneous water heater.
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.