New Gas Pipework Installation Chingford
- 11 hours ago
- 4 min read
Our team was called out to a property in Chingford to install a new Viessmann boiler. During the pre-installation survey, it became clear that the existing gas supply pipework wasn't going to be adequate for the new appliance's gas rate - a common issue we see across older Chingford homes where the original pipe run was sized for a much smaller, less efficient boiler decades ago.
The problem: the existing run included sections of 15mm pipe and 22mm pipe along its length, neither of which could reliably deliver enough gas volume at the working pressure the new Viessmann boiler needed at full output. Undersized pipework causes pressure drop under load — meaning the boiler can fire fine on a low demand but starve, fault, or under-perform when the system calls for full heat or priority hot water.
The fix: rather than a partial patch, our engineers re-ran the affected sections of pipework, upsizing 15mm to 22mm in the narrower runs and 22mm to 28mm where the existing 22mm pipe wasn't going to cope with the longer pipe run and additional appliance demand. This is a more involved job than a straight boiler swap, since it means assessing pipe diameter at multiple points along the route rather than a single uniform change-over, but it's the only way to guarantee the new boiler performs as the manufacturer intends — and that the installation is Gas Safe compliant.
Why Pipe Size Matters When You Upgrade Your Boiler
Gas pipework is sized to the appliance, not the building. A boiler's maximum gas rate, the length of the pipe run, and the number of bends all affect what diameter is required to maintain correct working pressure at the meter and at the appliance. Most modern combi and system boilers — including higher-output Viessmann models — need a 22mm supply as standard, with 28mm often required on longer runs or where multiple appliances are fed from the same pipe.
This is exactly the situation many Chingford properties run into: older 15mm or undersized 22mm pipework, installed for a boiler a fraction of the output of today's models, simply isn't rated for it. It's not a fault of the original installation — gas demand and appliance design have moved on. It's a compliance and performance issue that has to be addressed at the point of replacement.
Signs Your Gas Pipework May Need Upgrading
Your current boiler is significantly smaller in output than your planned replacement
Your home has a long pipe run from the meter to the boiler, or several bends and tees along the way
You're adding additional gas appliances (hob, fire, additional boiler) onto the same supply
An engineer's pressure test shows a drop under load
Your property was built or last re-piped more than 15–20 years ago
Our Process for Pipework Upgrades in Chingford
Survey and Pressure Test — We assess the existing pipe route, diameter, length, and number of fittings, and carry out a tightness and pressure test to confirm whether the existing pipework will support the new appliance.
Pipe Sizing Calculation — Using the manufacturer's gas rate for the specified boiler, we calculate the correct pipe diameter required along each section of the run, in line with Gas Safe and IGEM standards.
Pipework Installation — Affected sections are replaced with correctly sized pipe, tested for soundness, and routed to minimise disruption to walls, floors, and finishes.
Boiler Installation and Commissioning — The new Viessmann boiler is fitted, commissioned to manufacturer specification, and the installation notified to Gas Safe Register.
Why Choose LHS Plumbing Services for Gas Pipework in Chingford
Gas Safe registered engineers, fully insured
Manufacturer-approved Viessmann and Vaillant installers
Pipework sized correctly to the appliance — not patched or guessed
Local to Chingford, Loughton, Woodford Green, Buckhurst Hill, Wanstead, Chigwell, and Epping
All gas work certified and notified as required by law
Frequently Asked Questions
Will I need new gas pipework with every boiler replacement?
Not always. If your existing pipework is the correct diameter for the new boiler's gas rate and the run is a similar length, it can often be reused. An on-site survey is the only reliable way to confirm this.
How long does a pipework upgrade add to the installation?
A straightforward re-run of an existing route can usually be completed alongside the boiler installation in one to two days, depending on how much pipe needs replacing and how accessible it is.
Is upsized pipework more expensive to install?
There's additional material and labour involved compared with a like-for-like swap, but it's a one-off cost that ensures the new boiler runs at its rated efficiency and avoids fault codes or under-performance later.
Do I need a Gas Safe engineer for this work?
Yes. Any work on a gas supply pipe, by law, must be carried out by a Gas Safe registered engineer and is notifiable.
Need Your Gas Pipework Assessed in Chingford?
Call us today for a survey and fixed-price quotation.
Gas Safe registered engineers in Chingford E4
020 8111 1230
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