Tankless Water Heater Installation

Purpose

Installation procedure for tankless water heater systems by install crews.

Review Sales to Install form — verify all specs, location, and scope

Verify gas line sizing for tankless BTU demand (typically higher than tank)

Plan venting route — direct vent required for most units

Protect home with shoe covers and drop cloths

Remove old equipment, prepare installation location

Mount unit per manufacturer specs — proper clearances and support

Run or upgrade gas line as needed (properly sized for BTU requirement)

Connect water lines: cold inlet, hot outlet

Install condensate drain to approved drain point (condensate is acidic)

Install venting with 1/8 inch per foot pitch toward unit

Secure vent hangers every 4 feet

Fill system, check all connections for leaks

Pressure test gas connections, bubble test everything

Power on, run startup sequence per manufacturer

CO test at exhaust termination

Verify water temperature at fixtures

Set up recirculation system if in scope

Customer education: how tankless differs from tank, expected performance

Gas line sizing is critical — undersized line causes poor performance and error codes
Vent pitch matters — improper pitch causes condensate pooling (Navien 110-01)
Condensate is acidic — route properly, not onto concrete or soil
Recommend annual descaling maintenance
Strap iron may be needed for vent support in long runs