If you smell gas nowLeave the building without using switches, flames, or phones indoors. From outside, call 911 if there is immediate danger and call your gas utility. Contact a private-side contractor only after the area is declared safe.
The short answer
The full system needs a load calculation that considers the heater, route, fittings, meter capacity, and simultaneous appliance use. Venting, condensate, water, and electrical work are separate parts of the project that must also be assigned.
What matters in this situation
An appliance hookup is only as safe and reliable as the piping that feeds it. The existing branch, shutoff, connector, venting responsibilities, and combined gas demand all need to be understood before connection.
Details that help define the next step
- Tankless model and maximum input
- Distance from meter or main
- Existing pipe material and size
- Concurrent furnace, range, dryer, fireplace, or generator loads
These details help establish scope; they do not replace an emergency response, onsite inspection, utility decision, permit requirement, or manufacturer instruction.
How a careful service process is organized
- Start by documenting tankless model and maximum input and distance from meter or main.
- Confirm existing pipe material and size and concurrent furnace, range, dryer, fireplace, or generator loads before the scope is finalized.
- Have manufacturer installation manual and site photos and routing options ready for the onsite team or authority.
- Use the findings to define the appropriate gas appliance hookup scope, required testing, and any next authority or trade.
What to have ready when requesting service
- Manufacturer installation manual
- Site photos and routing options
- Current appliance schedule
- Utility meter information
What not to do
Do not assume a larger connector can solve an undersized permanent branch. Keep relevant tags, notices, equipment information, and safely obtained photos available for the people handling this specific situation.