cold water

What is the purpose of a double check valve when connected to drinking water?

To prevent backflow and contamination of the drinking water supply.

What is a pillar tap?

A common basin tap design that connects to a basin or sink via threaded tails.

What is the function of a draun-off tap?

It is used to drain a section of the system or pipework before repairs or freezing weather.

What does a water filter cartridge do?

It removes impurities like grit, sediment, and chlorine, improving the taste and appearance of water.

How does a base exchange softener work?

It replaces calcium and magnesium hardness with sodium using a resin bed.

What is the required air gap for overflow and warning pipes?

A 25mm air gap must be maintained between the pipe end and the water level.

What materials are commonly used for cisterns?

Cisterns are commonly made from polypropylene, plastic-lined copper, or galvanised steel.

What is the key difference between back-siphonage and back-pressure?

Back-siphonage occurs when pressure drops on the mains, sucking dirty water back in, while back-pressure happens when higher pressure in the system forces contaminated water into the mains.

What does a ball valve do?

It is commonly used for appliances like washing machines or dishwashers and allows full flow with easy quarter-turn operation.

What is a simple method for backflow protection?

Creating air gaps to prevent contact between outlets and stored or dirty water.

What is the purpose of covered, sealed tanks in water storage?

To avoid contamination.

How does elevated storage provide water pressure?

By gravity.

What is the primary source of water for cold water supply systems?

Mains water.

What type of system feeds everything directly from the mains?

Direct cold water supply system.

What are the advantages of using an indirect cold water system?

Reduces demand on mains during peak times and offers greater safety from contamination.

What is backflow in water supply systems?

Water flowing the wrong way, which can potentially contaminate the drinking water supply.

What is the first step in water treatment?

Sedimentation.

What does a deep well do?

Accesses deep groundwater, which is normally of good quality and less likely to be contaminated.

What are the four types of treated water?

Raw, untreated, potable, and hard/soft water.

What component prevents central heating systems from overheating due to pressure buildup?

Bypass valve.

What is the function of a three-port mid-position valve in a heating system?

It connects to both radiators and the hot water cylinder to control heating and hot water.

How does a cylinder thermostat operate?

It monitors water temperature in the hot water cylinder.

What type of well is known for being cleaner and sourcing water by pressure?

Artesian well.

What is a key characteristic of hard water?

It contains lots of minerals.

What is the treatment step that kills bacteria in water?

Chlorination.

What is a benefit of programmable room thermostats?

They allow setting different temperatures for different periods.

What should be checked in a central heating system to prevent air blockages?

Trapped air that can disrupt water flow.

What is the purpose of automatic bypass valves in heating systems?

To ensure minimum water flow when other valves close, reducing noise and increasing pump life.