Carterton, Oxfordshire, serving Witney, Oxford & the Cotswolds admin@pinnacle-plumbing.co.ukMon–Fri 8:30–5 · Sat & Sun emergency call-outs only AboutServicesGeneral Plumbing Repairs & MaintenanceEmergency Plumber & Call-OutsBoiler Installation & ReplacementBoiler Servicing & Gas SafetyBoiler Repairs & BreakdownsCentral Heating & Underfloor HeatingBathroom Renovations & InstallationsAir Source Heat Pumps & RenewablesLandlord Gas Safety Certificates (CP12)Estate & Letting Agent SupportNew Build & Development PlumbingRadiator & Valve Work Something not listed? Just ask — we take on most plumbing & heating work. View all → AreasWitneyCartertonOxfordOxfordshireAbingdonBicesterCotswoldsWoodstockMoreton-in-Marsh We also work outside these areas, including larger projects further afield. View all → Our WorkReviewsContact01865 306381Get a Free Quote New Boilers From £2,000 — 7+ years warranty, free fixed-price quote Get my quote Home/Services/Boiler InstallationBoiler Installation · Witney, Oxford & Oxfordshire # Fixed-Price Boiler Installationin Witney, Oxford& Oxfordshire. New A-rated boilers installed by Vaillant and Worcester Bosch approved engineers. Up to 10-year manufacturer warranty, fixed price agreed upfront, and a system left cleaner, quieter and more efficient than the day it went in. Get a Free QuoteCall 01865 306381 Installs from £2,000, quoted in writingVaillant & Worcester Bosch approvedKlarna finance available Up to 10-Yr Warranty On approved boiler installs Gas Safe Registered Every gas engineer individually qualified Vaillant Approved Extended manufacturer warranties Worcester Bosch Approved Full manufacturer register Klarna Available Spread the cost on larger jobs What we do ## Boiler Installation, explained properly. What it is A boiler installation replaces your existing gas boiler with a modern A-rated appliance (usually a combi, sometimes a system or regular boiler), sized correctly for your home, flushed and pressure-balanced, with new filter, controls and warranty registration. Who it's for Homeowners in Oxfordshire whose current boiler is over 10 years old, breaking down repeatedly, no longer meets efficiency requirements, or is under-sized for the way the household actually uses hot water. When you need it When repair costs approach a quarter of replacement, when parts are obsolete, when energy bills climb despite the same usage, or when the boiler no longer keeps up with modern demand (second bathroom, larger radiators, underfloor heating). Why a qualified team matters A boiler is only as good as the system feeding it. A cheap swap onto a dirty, unbalanced system voids warranties, wrecks pumps and diverter valves inside 12 months, and leaves you paying twice. We size, flush, filter and commission properly, that's what unlocks the 10-year warranty. What happens if it's left ## The cost of ignoring it. The wrong installer costs you three times: the wrong boiler, an install that voids warranty, and a system that fails inside two winters. ### Voided manufacturer warranty Vaillant and Worcester both require a magnetic filter, a proper flush and commissioning paperwork. Skip any of them and the 7–10 year warranty becomes 12 months. ### Under-sized (or over-sized) boiler Too small and you get cold showers when two taps run. Too big and you cycle constantly, waste gas and shorten the boiler's life. ### Sludge damage to a brand-new boiler Fitting a new boiler onto a heating system full of magnetite is like putting a new engine into a car with black oil. Pumps and heat exchangers fail fast. ### Ongoing high energy bills A poorly commissioned boiler runs at the wrong flow temperature, wrong pressure and wrong modulation range, costing hundreds a year in wasted gas. ### Common mistakes we see - •Choosing a boiler by output number alone, without a heat loss calculation for the home - •Reusing the old flue when regulations require replacement - •Skipping the system flush to save a day and £300 - •Not fitting a magnetic filter (Vaillant / Worcester now effectively require one) - •Failing to register the warranty within the manufacturer's window Our process ## How we run the job. - 01 ### Free home survey We measure the property, count the radiators, check hot water demand, inspect flue routes, gas meter and consumer unit, then recommend the right boiler, not the biggest. - 02 ### Fixed-price written quote One price covering the boiler, filter, flush, flue, controls, warranty registration and commissioning. Klarna finance options included on request. - 03 ### Install day Old boiler removed, new boiler installed with correct flue termination and gas pipework sized to load. Full-system chemical flush and inhibitor dosed. - 04 ### Commissioning & handover Flow temperatures set for your home's heat loss, controls paired, benchmark logbook completed, warranty registered with the manufacturer. - 05 ### Aftercare Annual servicing reminders and priority repair response for the life of the warranty. Benefits ## What you actually get. ### Up to 10-year warranty Standard 7-year manufacturer warranty on approved installs, extendable to 10 years, priced clearly in your quote. ### Lower running costs A correctly sized, correctly commissioned A-rated boiler uses noticeably less gas than a tired older unit running out of range. ### Quieter, more responsive heat Modern modulating boilers hold flow temperature steady. Radiators warm faster and shower temperature stops swinging. ### Klarna finance Spread the cost of a new install with Klarna. Ask for options in your quote. ### One team, one accountability The same team that installs comes back for the service. One point of contact, no finger-pointing. ### Clean, tidy install Old boiler and packaging removed. Floors and worktops covered. Home left as we found it. Recent work ## Real boiler installation jobs, real Oxfordshire homes. See full portfolio The detail ## Depth, not filler. Boiler installs aren't one product, the right specification depends on the property, the demand and the fuel supply. ### Combi boilers Best for most 1–2 bathroom homes with mains pressure above 1.5 bar. No cylinder needed, instant hot water, compact footprint. We fit Vaillant ecoTEC Plus, Worcester Bosch Greenstar 4000/8000 and Ideal Vogue Max, matched to your gas run and hot water flow rate. ### System boilers Better for larger homes with 2+ bathrooms simultaneously. Runs an unvented or vented cylinder, gives strong, balanced flow to multiple outlets. Common upgrade route from open-vent regular boilers. ### Regular / heat-only boilers The right choice when you already have a hot water cylinder, cold water tank and feed & expansion tank, often a straight swap that avoids re-routing pipework. ### Gravity-fed & open-vent systems Plenty of older Oxfordshire homes still run gravity-fed hot water: a cold tank in the loft, a vented cylinder in the airing cupboard and hot water pushed by head of water rather than mains pressure. We work on these every week. You have three routes: keep the system and fit a new heat-only boiler with proper pumped controls (fully pumped, motorised valves, cylinder stat and TRVs), keep the cylinder but upgrade it to an unvented cylinder on a system boiler for mains-pressure showers, or convert to a combi and remove the tanks entirely. Which one is right depends on your incoming mains flow rate and how many bathrooms need hot water at once, so we flow-test the mains at the survey before recommending anything. Converting gravity to combi with weak mains is the classic mistake, it turns a good shower into a dribble. ### Flue arrangements Horizontal, vertical, plume management kits for boundaries, high-level runs in Cotswold stone properties, building regs and distances from windows/openings are non-negotiable. ### Gas supply sizing Modern boilers demand more gas at peak than older ones. Where the existing 15mm run can't deliver it, we upgrade to 22mm as part of the fixed price. ### System protection Every install includes a full chemical flush, magnetic filter (Adey MagnaClean or Fernox TF1), Fernox F1 inhibitor and, where sensible, a scale reducer for hard-water areas. ### Controls & smart heating Programmable thermostats, wireless controls, Vaillant vSMART, Worcester Wave, Nest, Hive and Honeywell, properly integrated, not just clipped to a wall. ### Cotswold stone & listed properties Flue routing on stone-fronted properties needs care. We work around external aesthetics without compromising regs, talk to us early on listed properties. FAQs ## Straight answers. ### How much does a new boiler cost in Oxfordshire? Straight combi swaps typically start around £2,000 supplied, installed, flushed and commissioned with warranty registered. Full system upgrades with cylinder work or gas re-runs land higher. You'll always have a fixed written quote before committing. ### How long does an install take? A straight combi-to-combi swap is usually one working day. A conversion (e.g. regular to combi with cylinder removal) is 2–3 days. We'll tell you exactly in your quote. ### What warranty do I get? Standard installs come with a 7-year manufacturer warranty. Extended cover up to 10 years is available on approved Vaillant and Worcester ranges, priced separately in your quote so you decide. ### Do you offer finance? Yes, Klarna is available for boiler installations. We'll walk you through the options when we quote. ### Do I really need the flush and filter? Yes. Manufacturer warranty terms effectively require a system flush and magnetic filter. Skip either and warranty claims can be refused. It's built into every quote we send. ### Which boiler brand should I choose? For most Oxfordshire homes, Vaillant ecoTEC Plus or Worcester Bosch Greenstar are the strongest all-round choice. We're approved on both, so our recommendation is based on your home, not a sales bonus. ### Can you handle listed / stone-front properties? Yes, common across the Cotswolds. We route flues to comply with building regs while respecting the elevation. Talk to us early and we'll survey properly. ### What if my boiler dies before you can install? We prioritise no-heat and no-hot-water calls. If you're waiting on an install we can often provide a temporary fix or fast-track the replacement. ### Do you handle the warranty registration? Yes. We register with the manufacturer on your behalf and provide the benchmark logbook and paperwork you'll need for future service claims. ### I have a gravity-fed system with tanks in the loft, can you upgrade it? Yes. We can fit a new heat-only boiler and convert the system to fully pumped with proper controls, upgrade the cylinder to an unvented one on a system boiler for mains-pressure hot water, or convert to a combi and remove the loft tanks. We flow-test your incoming mains first, because a combi conversion on weak mains gives you worse showers, not better ones. ### Will a combi improve my shower pressure? Only if your incoming mains flow and pressure are strong enough. If they aren't, an unvented cylinder or a pump on a vented system will give you a far better shower. We measure before we recommend. ## Related services All services Boiler Service A proper boiler service: stripped, cleaned, tested and recorded, not a five-minute visual check. Learn more Boiler Repairs Locked-out combi, no hot water, weeping seal, fault code you don't understand? Gas Safe registered diagnostics, fixed price in writing, and the parts on the van to finish the vast majority of repairs on the first visit. Learn more Central Heating System upgrades, radiator installs, cylinder swaps, chemical cleans and wet underfloor heating designed and installed to work as one system, not a boiler stuck on top of tired pipework. Learn more Ready when you are ## Get a fixed-price quote for boiler installation in Witney, Oxford. Free, no-obligation quote in writing. Gas Safe registered, fully insured to £5m. Local team, real engineers, no call centres. Get a Free QuoteCall 01865 306381 Gas Safe RegisteredManufacturer Approved£5m Public Liability Gas Safe registered plumbing & heating engineers serving Oxfordshire and the Cotswolds since 2020. - ### Services General Plumbing Repairs - Emergency Plumber - Boiler Installation - Boiler Servicing - Boiler Repairs - Central Heating - Bathroom Renovations - Air Source Heat Pumps ### Areas - Plumber in Witney - Plumber in Carterton - Plumber in Oxford - Plumber in Oxfordshire - Plumber in Abingdon - Plumber in Bicester - Plumber in Cotswolds - Plumber in Woodstock - Plumber in Moreton-in-Marsh ### Contact - 01865 306381 - admin@pinnacle-plumbing.co.uk - Carterton, OxfordshireMonday – Friday8:30 AM – 5:00 PM Saturday & SundayEmergency call-outs only © 2026 Pinnacle Plumbing & Heating Direct Ltd. All rights reserved. Privacy policyTerms & conditionsGas Safe · £5m PL Call NowFree Quote