Understanding Unvented Hot Water Systems

Which of the following is a primary component of an unvented hot water system?

• Cold water storage cistern

• Expansion vessel

• Open vent pipe

• Feed and expansion tank

What is the main purpose of the temperature and pressure relief valve in an unvented hot water system?

• To increase water pressure

• To prevent overheating and over-pressurisation

• To filter impurities

• To reduce water temperature for taps

Which British Standard must unvented hot water systems comply with?

• BS 7671

• BS 6700

• BS 5440

• BS 7593

Who is legally allowed to install an unvented hot water system in Great Britain?

• Any competent DIY enthusiast

• A plumber with a G3 qualification

• An electrician

• A heating engineer without certification

What is the typical operating pressure for an unvented hot water cylinder in a domestic property?

• 0.5 bar

• 1.0 bar

• 3.0 bar

• 6.0 bar

Which component is responsible for accommodating the expansion of water as it heats up in an unvented system?

• Immersion heater

• Expansion vessel

• Pressure reducing valve

• Tundish

What is the function of the tundish in an unvented hot water system?

• To mix hot and cold water

• To provide a visible discharge point for safety valves

• To filter sediment

• To increase water pressure

Which of the following is NOT a required safety device on an unvented hot water cylinder?

• Temperature and pressure relief valve

• Expansion vessel

• Open vent pipe

• Pressure reducing valve

What is the recommended minimum discharge pipe size from a safety valve on an unvented cylinder?

• 10 mm

• 15 mm

• 22 mm

• 28 mm

During installation, what is the maximum permissible distance for the discharge pipe from the safety valve to the tundish?

• 300 mm

• 600 mm

• 1 metre

• 2 metres