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A Full Central Heating System Upgrade in Worcester Park, KT4

Project Overview

A homeowner in Worcester Park, KT4, contacted Plumb London after a routine annual boiler service revealed an immediately dangerous fault with their existing gas appliance. Following safe isolation of the system and a formal warning notice, the client chose to proceed with a full central heating upgrade, replacing the ageing boiler, all radiators, and outdated system components with a modern, high-efficiency installation. The completed project delivered a fully upgraded heating system with a new Vaillant ecoFIT Pure 625 boiler, ten new radiators, and a refreshed set of controls, all installed cleanly and commissioned to manufacturer standards.

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The Client’s Brief

The client needed a complete replacement of a condemned gas boiler that had been shut down on safety grounds, along with a full system overhaul to bring the property’s heating up to a modern standard. Their requirements were:

  • A reliable, high-efficiency replacement boiler with a strong manufacturer warranty
  • Relocation of the new boiler to a more practical position within the kitchen
  • Replacement of all existing radiators with new units fitted with thermostatic radiator valves
  • Updated system controls for improved comfort and efficiency
  • Minimal disruption to the property during works

Our Survey & Recommendations

During the initial service visit on 22 May, our engineer identified a cracked heat exchanger on the existing Potterton Kingfisher 2 CF50 boiler, a fault classified as immediately dangerous under Gas Safe regulations. The appliance was safely isolated, a formal warning notice was issued, and the system was made safe before the engineer left site.

A follow-up consultation confirmed the following:

  • The existing boiler was beyond economic repair and presented an active gas safety risk
  • The preferred relocation position for the new boiler was on the kitchen wall beside the window, with a new horizontal flue cored through the external wall
  • A fitted cupboard in the corner of the kitchen would need to be removed to allow for pipework routing
  • Given the age of the system, a full powerflush was recommended before installation to clear the existing pipework of sludge and debris
  • All ten radiators were assessed as requiring replacement
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Planning & Preparation

Following the initial service visit and safety shut-down in May, the client took time to consider their options and gather all relevant information before approving the works. The full scope was presented and agreed, with works commencing on 29 June. That short lead time let the client make an informed decision without any undue pressure, and gave our team enough time to procure all required materials ahead of the start date.

The Work We Carried Out

Strip-out and decommissioning

  • Safely isolated and fully drained down the existing heating system
  • Removed the existing Potterton boiler
  • Removed all ten existing radiators
  • Removed the existing heating tank and capped off the pipework
  • Removed the kitchen corner cupboard as agreed on site

Boiler and flue installation

  • Supplied and installed a Vaillant ecoFIT Pure 625 boiler with a 10-year manufacturer’s warranty, positioned on the kitchen wall beside the window
  • Cored a new flue aperture through the external wall
  • Installed a new horizontal flue assembly

Services and pipework

  • Carried out a full powerflush of the existing system before installation
  • Ran new gas, flow and return pipework from the original boiler position to the new location, routed under kitchen units by the most practical and least disruptive path
  • Connected new condensate pipework into the kitchen sink waste
  • Supplied and installed ten new radiators, each fitted with a TRV and lockshield valve

Controls, system components and commissioning

  • Supplied and installed a twin-channel programmer and room thermostat
  • Supplied and installed two Honeywell motorised valves
  • Supplied and installed an auto bypass valve, balancing valve and new filling loop
  • Carried out full pressure testing of all new pipework
  • Dosed the system with inhibitor to protect against corrosion and scale
  • Fully commissioned the installation and handed over to the client

A formal written testimonial was not obtained for this project. The works were completed to the client's satisfaction, the system was fully commissioned and signed off, and the project was delivered without issue.

Timeline & Completion

Works began on 29 June and were carried out as a single, continuous installation programme by our engineers Stefan and Darren, led by our senior engineer Mo. Given the scope, a full strip-out, boiler relocation, new flue penetration, ten radiators and a complete controls fit-out, the project was planned and resourced to minimise time without heating and hot water. It was delivered on programme, and the system was fully commissioned and handed over on completion.

Challenges & How We Solved Them

An immediately dangerous appliance requiring urgent resolution

The existing boiler was condemned during a routine service visit, leaving the property without heating or hot water and presenting a live gas safety risk. Our engineer acted immediately, safely isolating the appliance, issuing a formal warning notice, and making the system safe on the day. A full survey and quotation were turned around promptly, letting the client make a confident, informed decision without delay.

Boiler relocation and a new flue penetration

Moving the boiler from its original position to a new location on the kitchen wall needed careful planning. New gas, flow and return pipework had to be routed beneath the kitchen units with minimal disruption to the kitchen fabric, and a new flue hole had to be cored through the external wall. Our team planned the routing in advance and executed the penetration cleanly, with all new pipework concealed by the most practical and tidy route available.

An ageing system requiring a powerflush before installation

Fitting a new, high-efficiency boiler to an older system without first cleaning the pipework risks accelerated wear and reduced performance from day one. A full powerflush was carried out before installation to remove accumulated sludge, scale and debris from the existing pipework. The system was then dosed with inhibitor after installation to protect the new components and maintain efficiency long-term.

Kitchen cupboard removal and making good

The agreed relocation of the boiler required removing a corner cupboard in the kitchen to allow for clean pipework routing. This was discussed and agreed on site during the survey stage, so the client was fully prepared and there were no surprises on the day.

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The Finished Result

The property now has a fully modernised heating system built around a Vaillant ecoFIT Pure 625, one of the most reliable and efficient combination boilers currently available, backed by a 10-year manufacturer’s warranty. Ten new radiators fitted throughout the property, each with individual TRV control, give the client room-by-room temperature management and improved energy efficiency compared to the previous setup.

The boiler sits in its new position beside the kitchen window, a cleaner, more accessible location than the original, with all pipework neatly routed and a tidy flue exit through the external wall. The new controls, motorised valves and system protection components mean the installation meets current best practice standards and is set up for long-term reliability. The client went from a condemned boiler and no heating to a fully commissioned, modern system, all delivered from survey to handover within a matter of weeks.

Project Investment

Total investment: £13,950 plus VAT. This project represented a comprehensive investment in the long-term safety, comfort and efficiency of the property, covering a full strip-out, boiler relocation with a new flue penetration, ten new radiators, a powerflush, and a complete controls and system protection fit-out. For a household that went from a condemned boiler with no heating to a fully modernised system, backed by a 10-year manufacturer’s warranty, this reflects the scope and quality of a full system overhaul rather than a like-for-like swap.

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Why Choose Plumb London

At Plumb London, we don’t just replace like-for-like. We take the time to understand what a property actually needs and advise accordingly. Every installation is carried out by experienced, Gas Safe registered engineers, using quality materials from trusted manufacturers. We handle everything from the initial survey through to final commissioning and handover, keeping communication clear at every stage. We’re a family-run business with a reputation built on straightforward advice, quality workmanship, and looking after our customers properly, not just on the day of the job, but for the long term.

Frequently Asked Questions

My boiler has been condemned, what happens next?

If your boiler has been issued with a warning notice and shut down on safety grounds, it should not be restarted under any circumstances. Our team can arrange a survey at short notice to assess your options and provide a full quotation for a replacement. In most cases, a new boiler can be installed within a matter of days once the scope is agreed.

Do I need to replace my radiators when I get a new boiler?

Not always, it depends on the age and condition of your existing radiators and system. In this case, the radiators were replaced as part of a full system overhaul, which also included a powerflush to clean the existing pipework. Our engineers will always assess your radiators during the survey and advise honestly on what needs replacing and what can be retained.

What is a powerflush and why is it important?

A powerflush is a deep-clean process for your central heating system, using specialist equipment and chemicals to remove sludge, scale and debris that build up in older pipework over time. Installing a new boiler onto a contaminated system can significantly shorten the life of the new appliance and reduce its efficiency. We recommend a powerflush on all older systems before a new boiler installation.

What warranty comes with a new Vaillant boiler?

The Vaillant ecoFIT Pure range comes with a manufacturer’s warranty of up to 10 years when installed and registered by a Gas Safe registered engineer. Warranty terms may vary by model and registration, our team handles registration on your behalf at the point of commissioning.

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