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What is the main difference between sealed systems and open vented systems in terms of water?

• The color of the water

• The temperature at which water boils

• How the water is charged into the system and pressure maintenance

• The amount of water used

Identify the component labeled in the diagram that helps maintain pressure in a sealed heating system.

• Wiring centre

• Expansion vessel

• Programmer/stop

• Temporary filling loop with double check valve arrangement

How are sealed heating systems filled with water?

• Directly from the mains cold water supply via a permanent connection

• Using a temporary filling loop from the mains cold water supply

• Through an F&E cistern continuously

• By manual filling with buckets or containers

What replaces the open vent in a sealed heating system to manage the expansion of water?

• A pressure relief valve

• An expansion vessel and a pressure relief valve

• A thermostat

• A manual release valve

What is the purpose of the pressure relief valve in a sealed heating system?

• To increase the pressure within the system

• To regulate the temperature of the water

• To relieve excess pressure and discharge safely to a drain point outside the dwelling

• To indicate the water level in the system

Why is it vital to have a pressure relief valve in a sealed heating system?

• Because the water may be in excess of 80°C

• To prevent water from freezing in the system

• To maintain a constant water supply

• To control the pH level of the water

What does a pressure gauge in a sealed heating system help to indicate?

• The temperature of the water

• The quality of the water

• A potential component malfunction

• The amount of water used

What is the usual pressure to which a sealed heating system is pressurised?

• Around 2 bar

• Around 1 bar

• Around 0.5 bar

• Around 1.5 bar

Which of the following is NOT a type of sealed heating system mentioned in the text?

• Sealed systems with an external pressure vessel

• System boilers with all necessary safety controls

• Combination boilers

• Open vented systems with internal pressure vessel

Compared to two-pipe systems, what do older one-pipe systems require?

• Smaller diameters

• Larger diameters

• The same diameter

• No pipes