Gas Safe Registered · 574509 Ashford, Surrey & West London info@heatsolution.co.uk 07782 210675 AboutServices Areas Our WorkReviewsContactRequest a Free Quote - Home - Boiler & Heating Services - Unvented Cylinders Unvented Cylinders # Unvented Cylindersin Ashford, SurreyG3-qualified install & service Mains-pressure hot water to every tap in the house, installed, discharge-piped and safety-tested by a G3-qualified engineer, with the paperwork Building Control actually wants to see. Request a Free Quote 07782 210675 G3 qualified · Fixed-price quote · 267+ five-star reviews 24 yrs Trade experience Gas Safe Reg. 574509 £2m Public liability 2 yrs Workmanship guarantee Same day Emergency response Overview ## Unvented Cylinders, the essentials ### What it is Design, install, service and repair of unvented (mains-pressure) hot water cylinders. Full G3-compliant install including expansion vessel, PRV, tundish, discharge pipework to safe location, and annual servicing of the safety devices. ### Who it's for Family homes running multiple showers or bathrooms; system-to-combi replacement isn't always the right call, an unvented cylinder often gives better flow to multiple outlets. Larger properties, self-builds, extensions with second bathrooms. ### When you need it When you're losing hot water flow while a second tap is running; when replacing an old vented cylinder and loft tank; when converting a loft (freeing up the tank space); when installing a second bathroom. ### Why professional matters Unvented cylinders store hot water at mains pressure and include safety devices that MUST be installed and maintained correctly. G3 is the legal qualification for anyone working on them, installs by non-G3 engineers are unsafe and unnotifiable to Building Control. Why act now ## What ignoring the problem actually costs The mistakes that turn small jobs into big bills, and how a qualified engineer keeps them from happening. ### Non-G3 installs are dangerous Unvented cylinders can, in extreme fault conditions, become a pressure vessel with the energy of an explosion. G3 exists for a reason, an unqualified install skips the safety chain that prevents this. ### Missing discharge pipework A cylinder without correctly sized, correctly routed discharge pipework can't safely vent in a fault condition. Common on cheap installs; unacceptable to Building Control. ### Annual servicing skipped Expansion vessels lose pre-charge, PRVs seize, tundishes drip unnoticed. All catchable in a yearly service; all catastrophic if ignored for years. ### Wrong-size cylinder Undersized cylinders run out of hot water mid-shower; oversized ones cost a fortune to reheat. Sizing to actual demand matters. Our process ## A clear, predictable path from first call to guarantee - 01 ### Survey & sizing We check mains pressure and flow, number of bathrooms, expected simultaneous demand, and location for the cylinder and discharge pipework. - 02 ### Fixed-price quote Cylinder, expansion vessel, PRV, tundish, discharge pipe, controls and Building Regulations notification, all included, priced in writing. - 03 ### G3-qualified install Cylinder, safety group and discharge pipework installed to G3 spec, all pipework insulated, controls wired and configured. - 04 ### Commission and test Pressure tested, safety devices verified, working pressures recorded, cylinder brought up to temperature. - 05 ### Notification & hand-over Building Regulations notification and manufacturer warranty registered. 2-year workmanship guarantee on the install. What you get ## Concrete outcomes, not vague promises ### Mains-pressure hot water everywhere Every shower, tap and bath runs at full flow, no more losing pressure when someone flushes the loo. ### No loft tank required Frees up loft space (useful for loft conversions) and removes the risk of a tank leak from above. ### Multiple simultaneous outlets Two showers running at once without dropping to a dribble. ### Long-life stainless steel Modern unvented cylinders are typically stainless steel with 25+ year design life. ### Safe & compliant G3-qualified install, discharge to safe location, Building Regulations notified. Accredited & trusted by the brands we install The detail ## Unvented Cylinders, in depth Materials, methods and variations, the specifics that separate a proper install from a rushed one. ### Why G3 matters (legally and practically) G3 is the qualification for unvented hot water systems, it's part of the Building Regulations. Anyone installing, servicing or repairing an unvented cylinder must hold G3. Non-G3 work is not lawful and cannot be notified to Building Control. Calvin is G3 qualified. ### Safety device stack explained Every unvented cylinder needs: an expansion vessel (accommodating heated water expansion), a pressure relief valve (releasing water if pressure exceeds design), a temperature/pressure relief valve (belt-and-braces if the PRV fails or a thermostat fails), a tundish (visible air-break so you can see if the PRV is discharging), and correctly-sized discharge pipework routing safely to outside or a tundish drain. ### Sizing correctly 150L is entry-level for a small family; 210L is common for a 2-bathroom home; 300L+ for larger properties or high-demand households. Sizing is about simultaneous demand plus reheat time, undersizing is the more common mistake. ### Discharge pipework, the detail that's usually wrong The G3 rules on discharge pipework are specific, pipe diameter, maximum length, number of bends, and safe termination point are all defined. A properly designed install routes discharge to a visible outside termination or an approved internal tundish arrangement. Getting this wrong is the number-one failure point of non-specialist installs. ### Annual service, what it covers Expansion vessel pre-charge tested and re-pressurised, PRV manually operated to verify it seats correctly, T&P valve verified, tundish checked for signs of leakage, cylinder thermostat tested, working pressures recorded. All logged on a service sheet. Frequently asked ## Unvented Cylinders, your questions answered ### What is G3 and why does it matter? G3 is the qualification required under Building Regulations for anyone installing, servicing or repairing an unvented hot water cylinder. Non-G3 work is not lawful; Calvin holds G3. ### How much does an unvented cylinder installation cost? Depends on cylinder size, location, existing pipework and discharge routing. We survey and give a fixed written quote, no per-day surprises. ### How often should an unvented cylinder be serviced? Annually, the expansion vessel loses pre-charge over time and the safety devices need verification. It's also usually a warranty condition. ### Will I have hot water at every tap at full pressure? Yes, that's the whole point of unvented. The cylinder stores hot water at mains pressure so every outlet gets full flow, even with multiple taps running. ### Do I still need a cold water tank in the loft? No, unvented systems remove the need for a loft tank. This is one of the main reasons people convert during a loft conversion. ### What size cylinder do I need? 150L for a small home, 210L for typical 2-bathroom family homes, 300L+ for larger properties. We size it against your actual simultaneous demand at the survey. ### Is the install notified to Building Control? Yes, every G3-compliant install is notified under Building Regulations. You receive the compliance certificate afterwards. ### Is it guaranteed? 2 years on workmanship, plus manufacturer warranties on the cylinder and controls. Recent work ## Recent unvented cylinders projects A selection of real installs across Ashford, Surrey and West London, no stock photography. See more of our work Related services ## You may also need ### Boiler Installations Supply-and-fit new boilers, priced from £1,895. Learn more ### Central Heating Full installs, upgrades and system repairs. Learn more ### Bathroom Installations Design, supply and fit, or fit-only. Learn more ← Back to home·Contact us Gas Safe 574509 · £2m PL cover ## Ready to get unvented cylinders sorted?Free quote. Fixed price. Guaranteed. Speak directly to Calvin, 24 years on the tools, no sales scripts, honest advice. Request a Free Quote 07782 210675 Same-day emergency response · Free call-outs Gas Safe boiler and heating specialists serving Ashford, Surrey and West London. Fixed prices, tidy work and a 2-year workmanship guarantee. - 59 Hogarth Ave, Ashford TW15 1QB - 07782 210675 - info@heatsolution.co.uk - Leave a review ServicesBoiler Installations - Boiler Repair - Boiler Service - Central Heating - Underfloor Heating - Unvented Cylinders - Bathroom Installations - Plumbing - Gas Safety Certificates Service Areas - Ashford - Sunbury-on-Thames - Littleton - Feltham - Stanwell - Staines-upon-Thames - Shepperton - Twickenham - Teddington Company - About - Our Work - Reviews - Contact - Checkatrade - MyBuilder © 2026 Heat Solution London. Gas Safe Registered 574509. 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