Megaflo and Similar Quality Cylinders
We install recognised unvented cylinder systems, including Megaflo-style solutions and comparable quality products suited to the property.
Unvented Hot Water Cylinder Installation
Connected Gas & Heating installs and replaces unvented hot water cylinders across County Durham and the North East. These systems provide strong mains-pressure hot water and are fitted by qualified engineers under Gas Safe registration 186715, with fixed prices agreed before work begins.
- Strong mains-pressure hot water
- No traditional cold-water storage tank required
- Correct cylinder sizing for the property
- Safe installation with compliant discharge pipework
Unvented Cylinders Explained
What Is an Unvented Hot Water Cylinder?
An unvented cylinder is a sealed hot-water storage cylinder supplied directly by the incoming water main. It delivers hot water at mains pressure without relying on a traditional cold-water tank in the loft.
Better hot-water pressure for modern homes
Unlike an older vented or gravity-fed cylinder, an unvented system does not depend on the height of a loft tank to create pressure. This can provide stronger showers and more consistent hot-water flow, particularly in homes with more than one bathroom. The incoming mains supply must be suitable, and the cylinder must be correctly sized for the household's expected demand.
Qualified Installation
Why Unvented Cylinder Installation Must Be G3 Certified
Unvented cylinders store hot water under pressure. Their installation must meet the safety requirements of Building Regulations Approved Document G3 and be completed by an engineer qualified for unvented hot-water work.
Safety and Legal Compliance
The cylinder, expansion controls, safety valves and discharge pipework must all be installed correctly. These components protect the system if temperature or pressure rises beyond its normal operating range.
The completed installation must also be notified under the relevant Building Regulations process. Choosing a suitably qualified firm protects the property, supports compliance and ensures the system is commissioned properly.
Compare this work with a new boiler installationCylinder Options
Unvented Cylinders Sized and Installed for Your Home
We assess the household's hot-water use, number of bathrooms and available space before recommending a cylinder. Correct sizing matters because an undersized cylinder may struggle during busy periods, while unnecessary capacity adds cost and takes up space.
Correct Household Sizing
Cylinder capacity is selected around household size, expected hot-water use and the number of bathrooms or showers.
Multiple Bathroom Supply
A correctly designed unvented system can provide strong hot-water performance for homes with more than one bathroom.
Expansion Control
The expansion vessel or internal expansion arrangement must be sized, installed and commissioned correctly for safe operation.
Safe Discharge Pipework
Safety-valve discharge pipework is routed and terminated correctly so any discharge can be managed visibly and safely.
Replacement of Older Cylinders
We can assess an older vented or unvented cylinder and explain the practical replacement options for the existing heating system.
Ongoing Cylinder Care
Annual Servicing and Unvented Cylinder Safety Checks
An unvented cylinder should be serviced annually. Regular checks help confirm that the pressure, expansion and safety components remain in working order.
- Temperature and pressure relief valve. The safety valve is checked for condition and correct operation.
- Expansion vessel or expansion space. The engineer checks the arrangement used to accommodate heated water expansion.
- Discharge pipework. The route and visible discharge arrangements are inspected for signs of problems or unsafe alteration.
- Controls and operating condition. Relevant controls are checked and any unusual pressure or temperature behaviour is investigated.
Annual servicing is important because an unvented cylinder works under mains pressure and relies on dedicated safety controls. A dripping tundish, unusual pressure changes or repeated discharge should not be ignored.
For ongoing heating-system care, ask about annual cylinder servicing on a plan.
Where a wider low-temperature heating upgrade is planned, you can also explore underfloor heating installation.
Areas Covered
Unvented Cylinder Installation Across the North East
Connected Gas & Heating is based in Castle Eden and installs unvented hot-water cylinders across Sunderland, Seaham, Houghton-le-Spring, Hartlepool and Durham.
Wider coverage includes Middlesbrough, Stockton, Billingham, Newcastle, Washington, Gateshead, South Tyneside and surrounding communities.
- DH1–DH6
- SR1–SR8
- TS1–TS8
- TS15–TS29
Common Questions
Unvented Cylinder Installation Questions Answered
Do I need a special certificate to install an unvented cylinder?
Yes. An unvented cylinder must be installed by an engineer qualified for G3 unvented hot-water work. The installation must comply with Building Regulations Approved Document G3 and be notified through the appropriate Building Regulations process.
What is a Megaflo?
Megaflo is a recognised type of unvented hot-water cylinder. It stores hot water under pressure and supplies outlets directly from the mains, subject to suitable incoming water pressure and correct system design.
How often should an unvented cylinder be serviced?
An unvented cylinder should be serviced annually. The service checks important safety and expansion components, including the relief valve, expansion arrangement and discharge pipework.
What is the benefit of an unvented cylinder?
An unvented cylinder can provide strong mains-pressure hot water and removes the need for a traditional cold-water storage tank in the loft. It can be particularly useful in homes with more than one bathroom.
Can you replace my old hot-water tank?
Yes. We can assess an existing vented or unvented cylinder and explain the suitable replacement options. The incoming water supply, available space, heating system and household demand are considered before a fixed quote is provided.
Request a Survey
Get a Fixed Quote for an Unvented Cylinder
Tell us about your current hot-water system, number of bathrooms and any pressure problems. We will use the details to arrange the right survey and recommend an appropriately sized cylinder.
- G3-qualified unvented cylinder installation
- Advice on cylinder size and household demand
- Safe expansion and discharge arrangements
- Fixed price agreed before installation begins
Send a Cylinder Enquiry
Include your property type, bathroom count and details of the existing hot-water cylinder.
Page last updated: 22 August 2026