Project Overview
Plumb London recently completed a comprehensive heating and hot water system overhaul for a residential property undergoing a full renovation in Herne Hill, SE24. The existing setup was a patchwork of ageing components, a dual-boiler arrangement, a vented hot water cylinder, and cold water storage tanks, all of which were replaced with a modern, centralised system built around a Vaillant ecoFIT Pure system boiler and a 250-litre unvented indirect cylinder. The result is a far more efficient, reliable and space-conscious installation that serves the entire property from a single, well-engineered setup.
The Client’s Brief
The client was undertaking a full property renovation and wanted to modernise their heating and hot water infrastructure from the ground up. Their existing system was described as “messy”, a description the survey quickly confirmed. Their requirements were:
- Removal of the dual-boiler arrangement and consolidation into a single, modern heating system
- Elimination of cold and hot water storage tanks, freeing up valuable space within the property
- Resolution of persistent noise issues caused by rattling pipework
- A clean, efficient installation that would complement the wider renovation
- Professional guidance on the most suitable system type and optimal positioning within the property
Our Survey & Recommendations
Our engineer attended the property for an initial survey in late March, followed by a second visit in late May after the client had considered their options and refined their specification. The survey identified the following:
- The existing system comprised two separate boilers, one serving the ground floor and one dedicated solely to a standalone shower, along with vented hot and cold water storage tanks serving the upper floors. This arrangement was inefficient, space-hungry, and nearing the end of its serviceable life
- Rattling pipework was identified throughout, likely the result of unsecured runs and system pressure imbalances over time
Following discussion of the options available, the client opted for a system boiler and unvented cylinder configuration. This offers mains-pressure hot water throughout the property, eliminates the need for header tanks entirely, and gives a significantly cleaner and more controllable installation.
The preferred location for the new boiler and cylinder was at the top of the staircase, with a vertical flue taken through the roof, a position that would be concealed within the ongoing renovation works and allow pipework to be routed neatly through the fabric of the building. The client’s builder was already engaged to assist with roof works, and it was agreed that the roofer would be coordinated through them to form the weather-tight flue penetration.
Planning & Preparation
There was approximately two months between the initial survey visit and final confirmation of scope. This was entirely in keeping with the nature of the project, the client was making considered decisions as part of a wider renovation programme, and the specification evolved between the first and second visit as their priorities became clearer. Our engineer attended twice to make sure the final scope was technically sound and correctly aligned with the client’s vision before works commenced.
The Work We Carried Out
Strip-out and decommissioning
- Safely isolated and fully drained down the existing system
- Removed both existing boilers, the hot water cylinder, and cold and hot water storage tanks
Boiler, cylinder and flue installation
- Supplied and installed a Vaillant ecoFIT Pure 630 system boiler, located in the hallway cupboard at the top of the property, with a 10-year manufacturer’s warranty
- Supplied and installed a 250-litre Vaillant unvented indirect hot water cylinder at the same location
- Installed a vertical flue through the roof, coordinated with the client’s roofer and builder
- Fitted new lever isolation valves at the cylinder
- Carried out a full system powerflush, inhibitor dose, and commissioning
Pipework and services
- Ran a new gas supply from the meter to the boiler via the most practical route through the property
- Ran a new mains cold water supply from the existing stopcock to the new cylinder location
- Ran new flow and return pipework from the old boiler position to the new boiler, routed ready for a future underfloor heating manifold connection
- Ran new hot water distribution pipework from the cylinder to the existing hot water vent pipe
- Ran new discharge pipework from the unvented cylinder to the shower room waste pipe
- Ran new central heating pipework from the boiler to the radiator system
- Connected condensate pipework to the nearest suitable waste point
Controls and system components
- Supplied and installed three Honeywell motorised zone valves for independent circuit control
- Supplied and installed a Vaillant magnetic system filter, auto bypass valve and filling loop
- Reconnected and wired the client’s existing Nest thermostat to the new system
- Ran a new electrical cable in readiness for a future underfloor heating manifold
As a recommended addition, we also supplied and installed an AquaBion water conditioner on the incoming mains supply to reduce limescale build-up and protect the new system.
A formal written testimonial was not obtained at the time of project completion. The client was fully satisfied with the works carried out and the standard of finish delivered, and we look forward to supporting them through the next stages of their renovation.
Timeline & Completion
The installation was carried out over two days with a two-person team, led by our senior engineer Mo, in line with the programme agreed at quotation stage. Works were delivered on schedule and coordinated with the client’s wider renovation programme, with the builder and roofer managing the flue penetration in parallel.
Challenges & How We Solved Them
Complex multi-zone pipework routing through an occupied renovation site
With building works already underway throughout the property, routing new gas, water and heating pipework needed careful planning to avoid conflict with other trades. Our engineer mapped the most practical route on site during the survey, running pipework alongside the bedroom wall where fitted cupboards would conceal it, and through the office floor, giving a tidy finish that would be fully hidden within the completed renovation.
Vertical flue installation through the roof
A standard horizontal flue wasn’t feasible given the boiler’s position within the property. The vertical flue route needed coordination with the client’s roofing contractor to form a properly weather-sealed penetration. We scoped this into the programme from the outset, liaising directly with the client’s builder so the works were completed in sequence without delay.
Transition from a vented to an unvented system
Replacing a vented cylinder and storage tank arrangement with a pressurised unvented system brings a number of regulatory and technical requirements, including G3 compliance, discharge pipework, and correct cylinder positioning. Our engineer addressed all of these in full, including a dedicated discharge run to the shower room waste, and the system was commissioned and signed off in line with current Building Regulations.
Future-proofing for underfloor heating
The client’s renovation included plans to install underfloor heating at a later stage. Rather than require a costly second mobilisation, we routed the heating flow and return and a dedicated electrical cable to the planned manifold position during the primary installation works, so the underfloor heating can be connected with minimal disruption when the time comes.
The Finished Result
The completed installation delivers a clean, modern heating and hot water system that bears no resemblance to the cluttered arrangement that preceded it. Both the boiler and cylinder are neatly housed at the top of the property, the redundant tanks are gone entirely, and the pipework runs are concealed within the building fabric. The client benefits from mains-pressure hot water throughout, a single point of control via their existing Nest thermostat, and a system that’s fully prepared for the next phase of their renovation. The noise issues that characterised the old system are resolved, and the installation carries a 10-year manufacturer’s warranty on the boiler as standard.
Project Investment
This project was completed at a total cost of £14,950 plus VAT, a considered investment in the long-term performance, efficiency and value of the property. Given the scope of work involved, the complexity of the pipework routing, and the future-readiness built into the installation, this represents excellent value for a system designed to serve the property reliably for decades.
Why Choose Plumb London
- End-to-end expertise. From initial survey and technical consultation through to commissioning and handover, every stage is managed by our own experienced team
- Manufacturer-backed products. We work with leading brands including Vaillant, Honeywell and Nest, ensuring quality components with full warranty support
- Transparent, detailed scoping. Our quotes are thorough and specific, so clients know exactly what is included before works begin
- Trade coordination. We work alongside builders, electricians and roofers as part of wider renovation programmes, so our works integrate seamlessly with the wider project
- Fully compliant installations. All works are carried out in accordance with current Gas Safe, Building Regulations and manufacturer requirements
Frequently Asked Questions
What is the difference between a system boiler and a combi boiler?
A combi boiler heats water on demand directly from the mains, making it well suited to smaller properties with moderate hot water needs. A system boiler works with a separate hot water cylinder, which stores a larger volume of pre-heated water, making it the preferred choice for larger homes or properties where multiple outlets may be in use simultaneously, delivering mains-pressure hot water without any compromise on flow rate.
What is an unvented hot water cylinder, and why is it preferable to a traditional vented cylinder?
A traditional vented cylinder relies on a header tank in the loft to maintain water pressure, which often results in disappointing flow rates, particularly on upper floors. An unvented cylinder connects directly to the mains, delivering hot water at full mains pressure to every outlet in the property, and eliminates the need for roof space storage tanks entirely, freeing up space and removing a source of potential contamination.
What is a powerflush, and is it necessary on an existing system?
A powerflush is a deep clean of the heating system using high-velocity water and specialist chemicals to remove accumulated sludge, scale and debris from the pipework and radiators. On an existing system, this build-up is almost universal and, if left untreated, will significantly reduce the efficiency and lifespan of a new boiler. We include a powerflush as standard on all system replacements into existing pipework.
Can the system accommodate underfloor heating in the future?
Yes, and in this case, we specifically planned for it. During the installation we routed heating flow and return pipework and a dedicated electrical cable to the intended manifold location, meaning the underfloor heating can be connected at a later date without any need to revisit the boiler or re-run services. This kind of forward planning is something we encourage on all renovation projects.
Customer Testimonials
Don’t just take our word for it, here’s a selection of the latest reviews. You can view more here.
Excellent service by Plumb London, fixed two bathroom related issues in a couple of days - clear communication and good management of expectations in terms of works and timeline, which I always apprec..Read More
Sandra Obradovic
Really happy with the service from Plumb London for my toilet repair. We're quick to attend and Charlie was very knowledgeable, getting the specific part needed and even providing advice on some other..Read More
Darren Phillips
Plumb London were brilliant from quote to completion. Firstly, they are very competitively priced and I had very little hesitation going with their quote for a new boiler. I was also really impressed ..Read More
Ashley Watkinson
Our boiler was leaking and Nicola fixed it the day it happened. Highly recommended!
Kathy Weston
Brilliant service, friendly engineer and a job completed quickly and tidily. I would use the company again if I ever need to. Swanscombe, Kent
Collin Best
Plumb London were able to come quickly and fix my problem without fuss, quoting a sensible price.
Robert Slater
My toilet seat was broken and previous plumbers I contacted told me it was a non-standard toilet and I had to get a new toilet. I invited over Plumb London and they told me that the toilet seat can be..Read More
Geoffrey Payne
Plumb London provided excellent service from start to finish! The boiler installation was quick, tidy, and professionally done. A year later, the same engineer carried out an efficient and thorough ma..Read More
George Ezeanaka
Fantastic experience all around. The customer service team at PlumbLondon is not only responsive and super-friendly, but actually take initiative - we had our job done a day early because a team membe..Read More
Eleanor Franzén
Plumb London carried out a boiler and gas safety check for me. They were quick to get booked in, the team were polite and professional, and their pricing was more competitive than others I contacted. ..Read More
Louise Kaufhold
A Five Star service. The range of skills and craftsmanship displayed by Mounir were incredible. Would recommend to anyone with dreams of creating a Dream Kitchen. With this Team, it’s not just possi..Read More
Trevor Beattie
Easy to communicate with and quick work to solve the problem we had
Josh Evans
Excellent service from start to finish, everything was handled professionally and efficiently. Communication was clear throughout, and Louise did a great job coordinating everything and keeping me in..Read More
Claire Willis
Plumb London were brilliant. Stephan turned up on time, was very personable and was very efficient. Would definitely recommend and will be using again in future.
Eleanor Rider
For the second year in a row, the lovely Mo serviced our boiler. He was on time and provided a super thorough service. I would really recommend Plumb London as your plumbing company. 5 stars all round..Read More
Dianah Jane Coleman
Very fast service. We got our boiler changed as an emergency a year ago, and got service this year. Both times Plumb London were booked within 24h of being called, with the team taking good care of en..Read More
Alexandra Fleming
Great professional service from start to finish. The team did an excellent job installing a Powertank and paid close attention to detail throughout. I’ve used them a couple of times now and have alw..Read More
Kevin Senior
Absolutely exceptional service. Cannot recommend enough. Polite, attentive and understanding of the situation. Par and Stephan who attended my property were courteous and professional, making the horr..Read More
Max Hurd
I can’t fault the service I received. Prompt, courteous and so accommodating. It’s so easy to be ripped off, PlumbLondon are overwhelmingly decent, thorough and reliable. A million percent recomme..Read More
Kate Comer
Amazing job the works is done very professionally I will not hesitate to use your company again and recommend to friends.
Renato Balane
Fantastic service, efficient and easy to organise. Reliable and fair pricing
Jane Renton-Rose
Very professional and comprehensive service.
Stuart Highley
Fast service (next day) for the initial assessment of the issue. Then, even though it was not an emergency per se (needed broken shower pump replaced and associated inter-connecting pipe work), the te..Read More
Jeff Smith
a five-star service
David Akers
I had a great experience with Plumb London. They came out quickly to inspect an issue with my water tank, identified the problem right away, and got everything sorted efficiently. The engineer was pro..Read More
Patrick Fuller
Delighted with the service from Plumb London on a number of occasions. Very reliable and professional.
Thomas Jacques
good job well done boiler replacement
Deirdre Bell
Excellent service from engineer who attended to change kitchen tap. Punctual, courteous and knowledgeable. Got the job done despite an unexpected issue with some complex piping (resolved on the spot)...Read More
Constantia Smith
Contacted Plumb London hi Charlie, come round and give me a quote within days. Carried out. I ordered all the parts and even matched The new tiles with the existing. Hardly recommend them very profess..Read More
Vimal Sharma
Very professional. The work was carried out efficiently and quickly.
matt o'neill
Amazing job the works is done very professionally I will not hesitate to use your company again and recommend to friends.
Renato Balane
Fantastic service, efficient and easy to organise. Reliable and fair pricing
Jane Renton-Rose
We recently worked with Plumb London at AKA Marylebone and were extremely impressed with their professionalism and technical expertise. The project involved complex plantroom systems and ongoing comm..Read More
shellie-ann delaney
Excellent service. I've used Plumb London multiple times and they're always professional (they pick up the phone and arrive when they say they will). For example, my boiler had been leaking but only o..Read More
Sebastian Robinson
The initial consultation from Plumb London was excellent, and then a call received quickly do explain a detailed quote. The appointment for the work was quick and the work to the bathroom carried out ..Read More
Nick M
Had a new boiler installed 4 years ago, best decision. They have looked after it well and every service is efficient, quick and easy. They are fantastic to book with, always answer the phone and any i..Read More
Milly Smith
Big thumbs up for Plumb London, in particular the engineer (Andrew) who visited the property where my elderly mother lives. A gentle manner and patient approach was exactly the level of kindness that ..Read More
Patrick Totty
Prompt and efficient service from Plumb London. A clear and comprehensive quote was provided and the job was completed well. Our ancient boiler completely stopped working and they were able to visit t..Read More
Simone Thomas
Plumb London were absolutely incredible. We were in an emergency situation, and Jack did everything he possibly could to get a new boiler out to us as quickly as possible. He also liaised directly wit..Read More
Lily Macpherson
Fabulous and prompt service. Kept up to date; great communication.
Paula Kennedy
Great job, quick efficient and fair price
Daniel Dean
Delighted with the service from Plumb London on a number of occasions. Very reliable and professional.
Thomas Jacques
The service from Plumb London was prompt and they have solved the problem as I have still not had a complaint from my tenants It was very easy to deal.with the staff at Plumb London.
Shubha Kasbekar
Excellent service from engineer who attended to change kitchen tap. Punctual, courteous and knowledgeable. Got the job done despite an unexpected issue with some complex piping (resolved on the spot)...Read More
Constantia Smith
Excellent service by Plumb London, fixed two bathroom related issues in a couple of days - clear communication and good management of expectations in terms of works and timeline, which I always apprec..Read More
Sandra Obradovic
Really happy with the service from Plumb London for my toilet repair. We're quick to attend and Charlie was very knowledgeable, getting the specific part needed and even providing advice on some other..Read More
Darren Phillips
Contact Plumb London
If you are facing a plumbing, heating, boiler or drainage issue in London, do not hesitate to get in touch with Plumb London. Our friendly and knowledgeable team is ready to assist you with all your plumbing needs. Reach out to us today to schedule a consultation and experience the difference with Plumb London.
