When the day of your boiler installation arrives, it's natural to feel a mix of excitement and concern. A new boiler means better heating performance and greater energy efficiency, but you might also wonder how disruptive the process will be. This blog walks you through exactly what to expect on installation day, from start to finish, so you can feel confident and prepared.
What happens during a boiler installation?
Whether you're having a boiler installed in Bournemouth, Poole or Wimborne, the process is generally straightforward when carried out by a qualified Gas Safe registered engineer. Here's how a typical installation day is structured.
Arrival and Preparation
Your heating engineer will arrive at the scheduled time and begin by confirming the installation plan. They may ask a few final questions to ensure everything is as expected. Before work begins, dust sheets or floor protectors will be laid down in key areas like hallways or utility rooms.
Safety is the first priority. The installer will isolate the gas, water, and electric supply to the old boiler before removal. If you have underfloor heating connected to the system, this will be taken into account during the preparation.
Removal of the Old Boiler
The next step is to carefully disconnect and remove the old boiler. This includes detaching pipework, removing the flue, and draining any remaining water in the system. If you’re replacing a combi with a system boiler or relocating the unit entirely, additional work will be required—this could extend the duration by several hours or even into a second day.
Removing the old system often reveals wear and tear or sludge within your central heating pipework, which is why many installers will recommend a system flush at this stage.
System Flush (if required)
To improve system health and protect your new boiler, your engineer may carry out a chemical flush or power flush. This helps remove any debris or rust buildup that could otherwise cause future problems such as poor circulation, cold radiators, or boiler faults.
Fitting the New Boiler
Once the area is prepared and cleaned, the new boiler is installed and mounted (if wall-hung). All necessary connections are made, including gas, water, central heating pipes, and electrics.
If your home in Poole or Bournemouth also includes modern heating controls like smart thermostats, this is the stage where those get wired in and tested.
Installation of New Flue and Controls
A new flue will be fitted to safely vent waste gases from your boiler. This may go through an outside wall or the roof, depending on the boiler's location. The installer will also connect any new heating controls or thermostats and check all components for safe and effective operation.
Final Testing and Commissioning
The final phase is a detailed series of tests to ensure your new boiler is running properly. The installer will check gas pressures, flue integrity, thermostat response, and verify that all radiators heat evenly. You’ll receive an overview of the system’s functions, plus tips on setting your heating schedules and saving energy.
You’ll also be given the necessary documentation, such as:
- Gas Safe certificate
- Building regulations certificate (if applicable)
- Manufacturer warranty information
How Long Does a Boiler Installation Take?
In most homes across Dorset, a like-for-like combi boiler replacement can be completed in 4 to 6 hours. However, installations that involve repositioning the boiler, changing system types (e.g. combi to system), or additional services like power flushing can take 1.5 to 2 days.
Planning ahead with this timeframe in mind helps minimise disruption.
Will You Be Without Heating and Hot Water?
Yes, your heating and hot water will be temporarily unavailable during the installation. If the work takes more than a day, your installer will let you know in advance so you can make alternative arrangements, such as using immersion heaters or portable radiators.
What to Do Before Your Installer Arrives
To make the process smoother:
- Clear the area around your boiler for easy access
- Move any valuables or furniture from the workspace
- Keep pets and children away from work zones
- Make a note of any specific heating issues you want to raise
Aftercare and First Service
Once installation is complete, your engineer will advise when to book your first boiler service—usually within 12 months to maintain your warranty. Homeowners in Wimborne and Poole should consider annual boiler servicing as a long-term investment in efficiency and safety.
Planning a boiler installation in Bournemouth, Poole, or Wimborne?
Wood & Williams provides boiler installations and replacements backed by reliable customer support. Whether you're upgrading your heating system or fitting a new one, we're here to help. Call us on 01202 497311 or fill out our contact form to book your installation and get started today.