Telford Tempest unvented cylinders

Telford Tempest models and systems

Faults we diagnose

A cylinder can be blamed when the actual fault sits in the electrical supply, Economy 7 switching, immersion heater, thermostat, wiring, motorised valve, boiler/heat-pump heat source, pressure controls or discharge arrangement. We test the relevant system before recommending a replacement.

Installation and replacement

For replacement we check usable cupboard space, cylinder capacity, mains pressure and flow, discharge route, direct versus indirect heat source, electrical circuit, immersion strategy and future plans such as solar PV or a heat pump. In London flats we also plan access, leasehold constraints and compact/slimline options where relevant.

Direct electric and Economy 7 cylinders

Direct cylinders commonly use one or more immersion heaters. In an Economy 7 property the lower immersion is often arranged for off-peak heating while an upper immersion provides a boost. If the overnight hot water disappears but boost still works, the fault may be in the off-peak supply, switching, circuit, thermostat or immersion element rather than the cylinder shell.

Unvented safety and servicing

Unvented systems operate with safety controls and discharge arrangements that must remain functional. Servicing is more than checking for leaks: controls, valves, expansion provision and the discharge path are inspected in line with the system type and current manufacturer instructions. We do not bypass safety devices to keep a cylinder running.

Related pages

Manufacturer status

Telford Tempest cylinder systems

Telford's Tempest name is associated with unvented stainless-steel cylinders across direct, indirect and renewable configurations. The exact suffix and connection layout matter because they determine how the stored water is heated and controlled.

For direct-electric systems, we test the immersion circuit before condemning the cylinder. For indirect systems, we also check whether the primary heat source is reaching the coil and whether the control valve and thermostat are operating correctly.

Space and access

Tempest products are available in different diameters and capacities, so replacement planning includes cupboard width, height and access for future servicing rather than selecting by litres alone.