Boiler Installation Day: What to Expect

Knowing what to expect on installation day reduces stress and helps everything run smoothly. Here's a realistic timeline for a standard like-for-like combi replacement.

Before the engineers arrive

• Clear the area around the boiler — remove everything stored in the airing cupboard or boiler area
• Locate your stopcock (mains water shutoff) and gas meter
• Protect flooring near the work area with an old sheet or tarpaulin
• Plan for no hot water or heating during the day

Morning (8:30–10:00 am): Assessment and shutdown

Engineers arrive, briefly assess the job, confirm the plan, and shut down the existing system. Gas is isolated at the meter. Water is isolated at the mains.

Late morning (10:00 am–12:30 pm): Removal

The old boiler, flue, and any associated components are carefully removed. System water is drained. Old pipework is cut and capped as needed.

Early afternoon (12:30–3:30 pm): Installation

The new boiler is positioned and mounted. New flue is fitted and routed. Gas connection is made and tested for leaks. Water connections are made and the system is filled and bled. Magnetic filter, inhibitor, and any new controls are fitted.

Late afternoon (3:30–5:00 pm): Commissioning

The boiler is started up and run through a full commissioning procedure. Combustion analysis is performed. All controls are tested. Pressure and temperature checked at working load.

Handover

Engineers walk you through the controls and explain how to re-pressurise if needed. All certificates (Gas Safe, Building Regulations) are provided. Any questions are answered before leaving.