Unvented Cylinder Installation

Mains-pressure performance – safe, powerful, and certified.

Installation: We are G3-qualified engineers (legal requirement) to install unvented cylinders (megaflow-style) in domestic homes. These run directly off the cold mains, delivering high-pressure hot water (3+ bar) without pumps. We install the mandatory expansion vessel, pressure reducing valve, temperature & pressure (T&P) relief valve, and tundish with visible discharge pipework to Building Regulations Part G3. We also size the cylinder for simultaneous multiple outlets (e.g., two showers running at once).

Service: Annual G3 safety checks are critical. We test the expansion relief valve, T&P valve, and pressure reducing valve for proper operation and no sticking. We check the internal bubble-top air gap (or expansion vessel pre-charge pressure) and top up if needed to prevent weeping from the tundish.

Repair: We troubleshoot pressure loss, intermittent high-temperature cut-outs, and failed immersion heaters. We replace faulty pressure reducing cartridges, expansion vessels (if bladder fails), and thermostat probes. All repairs come with a written safety certificate.