Hot water system safety

Open Ended

What measures have been introduced to reduce the risk of scalding from hot water in homes?

Multiple Choice

Which of the following devices helps reduce the risk of explosion in unvented hot water systems?

• Boiler stat

• Pressure gauge

• Water softener

• Flow restrictor

Multiple Select

Which of the following statements about legionella are correct?

• Legionella will grow between 20–46ºC.

• Legionella is killed at 47ºC and above.

• Legionella grows best below 10ºC.

• Legionella is not affected by temperature.

Open Ended

Explain why it is important to install high efficiency (HE) boilers in domestic hot water systems from an environmental perspective.

Multiple Choice

What is a common consequence of heating hard water to 65ºC or above?

• Lime scale is produced

• Water becomes softer

• Bacteria multiply rapidly

• Water turns acidic

Open Ended

Describe the main purposes of storing hot water at a high temperature and distributing it at a lower temperature in plumbing systems.

Open Ended

Explain the function of a blending valve in a plumbing system and why it is important for safety.

Multiple Select

Which of the following appliances can be fed from a single thermostatic mixing valve (TMV) in group mixing installations? Select all that apply.

• Wash basins

• Showers

• Kitchen sinks

• Baths

Multiple Select

Which of the following are components used for temperature control in plumbing systems?

• Cylinder stat

• Boiler stat

• Tap stat

• Pressure gauge

Open Ended

Describe how a tap stat operates in older plumbing systems and its role in temperature control.

Multiple Choice

Which component in a boiler is responsible for regulating the primary water temperature that flows to the coil?

• Thermostat

• Pressure relief valve

• Immersion heater

• Insulation

Open Ended

Explain the function of a temperature/pressure relief valve in plumbing systems and why it is important for safety.

Multiple Choice

Which of the following statements about immersion heaters is correct?

• They must have a resettable double thermostat as standard.

• They do not require any safety cut-off device.

• They are not regulated by any standards.

• They only use a single thermostat.

Multiple Select

Which of the following are desirable characteristics of good insulating material for plumbing applications?

• Not flammable

• Vermin-proof

• Impervious to moisture

• Conducts heat easily

Multiple Choice

Which of the following components or pipework should be protected with insulation according to the guidelines?

• Outside pipework

• Pipework in the roof space

• Service pipes (750–1,350mm)

• All of the above

Open Ended

Explain why it is important to insulate cold water storage cisterns and describe the recommended method for doing so.

Multiple Select

Which of the following are recommended materials for pipe insulation?

• Rigid phenolic foam

• Polyisocyanurate foam

• PVC foam

• All of the above

Open Ended

What questions do you still have about hot water system safety and efficiency?

Multiple Choice

Why is it important to control the temperature of domestic hot water systems?

• To prevent scalding accidents

• To reduce water usage

• To improve water taste

• To increase water pressure