Unvented hot water cylinders

Installation, annual servicing and repair of unvented hot water cylinders, carried out under the HWSS qualification that Building Regulations G3 requires.

• Megaflo, Gledhill, Telford and equivalent systems
• Full install including expansion vessel, discharge pipework and tundish
• Annual service, which the manufacturer warranty depends on
• Low pressure and no hot water faults diagnosed properly
• Building Regulations G3 notification handled
• Sized to the number of bathrooms you actually have

What an unvented cylinder gives you

An unvented cylinder runs at mains pressure, so you get a proper shower without a pump, and you can run more than one outlet at once without the flow collapsing. In a house with two or more bathrooms it is usually a better answer than a combi, because a combi can only heat water as fast as it flows through.

The trade-off is that it stores a fixed amount of hot water, so sizing matters. Too small and you run out mid-shower on a Sunday morning; too big and you pay to keep water hot that nobody uses.

Why it must be G3 certified

An unvented cylinder is a pressure vessel holding water above 100°C at pressure. If the safety devices fail and nobody notices, the failure is violent. That is why Building Regulations Part G3 requires the installer to hold a specific qualification, requires the work to be notified, and requires annual servicing of the safety devices. We hold HWSS and every install we do is notified.

Servicing

The annual service checks and recharges the expansion vessel, tests the temperature and pressure relief valve, checks the immersion heater and thermostat, inspects the discharge pipework and tundish, and descales where West London's hard water has taken its toll. Skipping it is how a cylinder ends up dumping water through the tundish, and it is also how manufacturer warranties get refused.