Components used in domestic hot water system

Multiple Choice

Which of the following is a current method for heating water in a direct cylinder?

• Directly from the boiler

• Via an immersion heater

• Using a heat exchanger coil

• Using solar panels

Multiple Choice

Which components are involved in the heating process of a direct cylinder as shown in the diagram?

• Immersion heater, thermostat, cistern, primary flow pipe

• Coil type heat exchanger, boiler, cold feed cistern, vents

• Solar panel, expansion tank, pump, radiator

• Gas burner, pressure valve, outlet pipe, filter

Fill in the Blanks

Using a direct cylinder means the system only requires one

, hence the term single feed.

Open Ended

Explain the main differences between direct and indirect cylinders in terms of their heating mechanisms and water separation.

Multiple Choice

What is the function of the coil type heat exchanger in an indirect cylinder system?

• To heat the primary water directly

• To separate primary and secondary waters and transfer heat

• To store cold water for the system

• To control water pressure in the cylinder

Open Ended

Describe how the double feed system in indirect cylinders works and why two cisterns are needed.

Multiple Choice

Which type of cylinder uses a basic form of heat exchanger and fills the primaries at the same time as the CWSC?

• Prismatic cylinder

• Unvented cylinder

• Hot water cylinder

• Indirect cylinder

Open Ended

Explain the difference in feed source between prismatic cylinders and unvented cylinders.

Multiple Choice

Which of the following statements about unvented cylinders is correct?

• They operate under mains pressure and do not require a CWSC in the loft.

• They have an open vent and require a CWSC in the loft.

• They are always pre-pumped.

• They can only be heated directly.

Fill in the Blanks

Hot water cylinders in a standard system will only be fitted with one coil, which is heated by the

.

Multiple Choice

What are the options for additional coils in hot water cylinders to link other heat sources?

• Triple coil and quad coil

• Single coil and double coil

• Copper coil and steel coil

• Indirect coil and direct coil

Open Ended

Discuss the importance of insulation and material choice in modern hot water cylinders, referencing Building part L requirements.

Multiple Choice

How can the heat recovery time in hot water cylinders be reduced?

• By increasing the size and surface area of the coil

• By decreasing the temperature of the water

• By using less water

• By adding more insulation

Open Ended

Explain the role of a sacrificial anode in hot water cylinders and why it is important, especially in soft water areas.

Fill in the Blanks

The cylinder has a thermostat that regulates the domestic hot water temperature. This is placed

of the way up the cylinder.

Multiple Select

Which components are responsible for regulating water temperature in both the boiler and the cylinder?

• Thermostat

• Sacrificial anode

• Immersion heater

• Pressure valve

Open Ended

Compare the function and placement of immersion heaters in direct and indirect hot water cylinders.

Multiple Choice

What is the legal requirement for immersion heaters regarding the reset button, and why is it important for safety?

• It must be non-self-resetting

• It must be automatic

• It must be located outside the heater

• It must be resettable by remote control

Multiple Choice

Which component in an immersion heater is responsible for controlling the water temperature?

• Immersion element

• Thermostat

• Thermostat housing tube

• Immersion cover and lock nut

Multiple Select

Which of the following are controlled by a stat in a domestic hot water system?

• Boiler

• Immersion heater

• Hot water temperature

• Tap water pressure

Open Ended

Explain how the control of hot water temperature is achieved in a domestic heating system. Refer to the roles of different stats mentioned.

Fill in the Blanks

As domestic hot water heats up, the liquid inside the phial

and begins to close off the valve.

Multiple Choice

According to Building Regulations part G, what is the maximum temperature hot water delivered to a bath should not exceed?

• 38°C

• 48°C

• 100°C

• 46°C

Multiple Choice

At what temperature and above will legionella bacteria be killed off in domestic hot water systems?

• 20°C

• 38°C

• 47°C

• 100°C

Multiple Choice

What are the different types of corrosion in plumbing?

• Chemical corrosion,

• Temperature corrosion

• The different types of corrosion in plumbing include galvanic corrosion, pitting corrosion, and erosion corrosion.

• Rust corrosion,

Multiple Choice

What is the purpose of a sealed expansion vessel in a sealed heating system?

• To isolate the flow of water

• To prevent lock out and prolong circulator life

• To control the flow of water to the hot water cylinder

• To accommodate the increase in volume as the water heats up

Multiple Choice

When particles become hotter, they tend to move...

• Slower

• Faster

• At the same rate

• Backwards

Multiple Choice

When would a mirror screw be used on?

• Toilet

• Bath panels

• Basin

• Radiator

Multiple Choice

What symbol is shown here?

• Service valve

• 2-port zone valve

• Double check valve

• Gate valve

Multiple Choice

What is the minimum size of hot water pipework from a small combination boiler in a domestic property?

• 15mm
• 50mm
• 150mm
• 25mm

Multiple Choice

When removing floorboards, where possible you should cut:

• Cut over the joists

• Cut before the joist

• Cut after the joist

Multiple Choice

What is the diameter range for minibore/microbore copper pipes?

• 50mm and larger

• 28mm and larger

• 12, 15, 22mm

• 6, 8, 10mm

Multiple Choice

When would use a DZR brass fittings?

• For aesthetics

• Cold water installation

• Hot water installation

• Risk of dezincification

Multiple Choice

Copper bought in half hard straight lengths is:

• R220

• R290

• R250

• R230