The typical starting point
- Location
- Garage corner or closet, tank on a stand
- Venting
- Metal flue up through the roof
- Gas
- Line sized for a tank-era load
- Water lines
- Copper, or galvanized in some older homes
- Strapping
- Seismic straps on the existing tank
How the job usually unfolds
- Site visit
- The plumber checks the gas line, meter, vent options, outlet location, water lines and fixture demand.
- Written scope
- Unit, gas work, venting, valves, condensate, electrical and permit are listed in a written quote.
- Permit
- The contractor applies for any required permit; check with the City of Fullerton if unsure.
- Install day: removal
- Water and gas to the old tank are shut off, the tank is drained, disconnected and removed.
- Install day: new work
- The unit is mounted, gas piping and vent installed, service valves and relief valve fitted, and the condensate drain run if needed.
- Install day: testing
- Gas piping is tested, water is turned on, air is purged and the unit is fired at low and high flow.
- Inspection
- The inspector reviews the work; any corrections are made.
- Ongoing
- Flushing is scheduled to suit Fullerton's hard water.
Before install day
- Clear the area around the old tank and the planned vent exit
- Know where the main water shutoff and gas meter valve are
- Make sure the plumber has access to the gas meter
- Plan for no hot water for part of the day
- Confirm who handles the permit and inspection
What happens to the old flue and stand
If the tankless unit vents through a side wall, the old roof flue is no longer needed. It should be removed or properly capped and sealed so it does not leak or become a path for exhaust from another appliance. If another appliance, such as a furnace, shares that flue, the plumber needs to confirm it still vents correctly after the tank is gone.
The old stand and seismic straps go with the tank. Any wall penetrations left behind should be sealed, and the floor area cleaned so you can use the space.
Ask during the site visit
- Does a furnace or other appliance share the existing flue?
- Where will the vent exit, and how far is it from windows and doors?
- Is the gas line large enough, or will a new run be needed?
- Will you add service valves for flushing?
Common questions
How long is the house without hot water?
It depends on the scope. A plumber can estimate it during the site visit; plan for at least part of a day.
Do I need to be home during installation?
Usually at the start and end, and for the inspection. Confirm with the contractor.
Can the new unit go in the same corner?
Often, if the vent route and clearances work. The plumber confirms this during the site visit.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.