An unvented hot-water cylinder is connected directly to the incoming mains supply and stores water under pressure. Because of this, it incorporates specific safety devices and must be installed and maintained by people with the appropriate competence.
Why maintenance matters
The system relies on controls designed to manage temperature, pressure and expansion. Regular inspection gives an appropriately qualified engineer the opportunity to check the condition and operation of relevant safety devices in accordance with the cylinder manufacturer's instructions.
Expansion arrangements
Depending on the cylinder design, expansion may be accommodated by an external expansion vessel or an internal air gap. The correct maintenance procedure depends on the equipment installed.
Discharge pipework
Safety-valve discharge arrangements are an important part of an unvented installation. Any signs of persistent discharge or problems with the safety devices should be investigated rather than ignored.
Heat pumps and unvented cylinders
Unvented cylinders are commonly incorporated into heat-pump systems. Envirowarm's recent Kingswood HU7 heat pump service involved an integrated system with unvented hot water, solar thermal, solar PV and battery storage.
Hot-water servicing in Hull
Envirowarm works on heating and hot-water systems throughout Hull and East Yorkshire. Contact us with details of the cylinder and heat source if you need maintenance advice.