Wessex Water Approved
Water Safe Certified
Trenchless Technology Specialists
Domestic & Commercial
Wessex Water Approved
Water Safe Certified
Trenchless Technology Specialists
Domestic & Commercial
Sherborne Utilities

Unvented Cylinders

Installation and servicing of unvented hot water cylinders including Megaflo. Mains pressure hot water, energy efficient, G3 qualified engineers. Domestic and commercial across the South West.

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Unvented Hot Water Cylinder Installation & Servicing

An unvented hot water cylinder — such as the well-known Megaflo — is a mains-pressure hot water system that stores and delivers hot water at mains pressure. Unlike traditional vented hot water systems, which rely on a cold water storage tank in the loft to provide a gravity-fed supply, an unvented cylinder is connected directly to the mains cold water supply. This means hot water is delivered at the same pressure as your cold water — typically resulting in significantly better flow rates at showers, baths and hot taps.

Sherborne Utilities provides unvented cylinder installation and servicing for domestic and commercial clients across Dorset, Somerset, Wiltshire, Hampshire and Devon. The installation of unvented hot water systems is a regulated activity under Building Regulations Part G, and must by law be carried out by a G3 qualified engineer. All our unvented cylinder installations are carried out by appropriately qualified personnel.

We install a range of unvented cylinders from leading manufacturers including Megaflo, Telford, Range Tribune and others, in direct (electrically heated) and indirect (heated from a boiler) configurations. We can also specify and install heat pump-compatible cylinders for properties looking to move away from gas heating.

In addition to new installations, we carry out annual servicing of unvented cylinders — checking expansion vessels, pressure relief valves, temperature relief valves and all safety components in accordance with manufacturer requirements. Regular servicing is essential for the safe operation and long-term reliability of unvented systems.

Benefits of an Unvented Cylinder

Mains pressure hot water, better performance, greater flexibility and energy efficiency.

Mains Pressure Hot Water

Unvented cylinders deliver hot water at mains pressure — meaning powerful showers, fast-filling baths and strong hot water flow at every outlet throughout your property.

Energy Efficient

Modern unvented cylinders offer excellent insulation and can be paired with solar thermal, heat pumps and other renewable technologies for improved energy efficiency.

G3 Qualified Engineers

Unvented hot water systems must by law be installed by G3 qualified engineers. All Sherborne Utilities installations are carried out by appropriately qualified personnel.

Domestic & Commercial

We install unvented cylinders in domestic homes and commercial properties, sized and specified to meet the hot water demand of each application.

Our Unvented Cylinder Installation Process

Professional, compliant installation by G3 qualified engineers — from specification to commissioning.

01

Assessment & Specification

We assess the hot water demand of your property, the available mains pressure and flow rate, the space available for the cylinder and any existing heating infrastructure to specify the correct cylinder size and type.

02

Planning the Installation

We plan the installation including cylinder location, primary connections, cold water supply, expansion vessel positioning, relief valve discharge arrangements and electrical connections for immersion heaters.

03

Installation

The unvented cylinder is installed by our G3 qualified engineer, with all connections, safety components and controls fitted correctly in compliance with Building Regulations Part G.

04

Commissioning & Handover

The system is commissioned, tested and inspected. We register the installation with Building Control if required, provide all documentation and give you a full briefing on operation and maintenance.

G3 Compliance — Why it Matters

Unvented hot water cylinders operate at high pressures and temperatures. Building Regulations Part G requires that they are installed, commissioned and serviced by a competent person holding a recognised G3 qualification. Always ensure your installer is properly qualified — for safety, compliance and to protect your insurance cover.

Installation must be by G3 qualified engineer
Building Regulations notification required
Annual servicing strongly recommended
Safety relief valve discharge pipe required
Expansion vessel must be checked annually
Manufacturer warranty requires qualified installation

Service Areas

Unvented cylinder installation and servicing across Dorset, Somerset, Wiltshire, Hampshire and Devon. Based in Sherborne, we cover domestic and commercial clients throughout the South West.

Interested in an Unvented Cylinder?

Call Sherborne Utilities to discuss unvented cylinder installation for your property. G3 qualified. Domestic and commercial. South West specialists.

01963 23200