Plumbing and Heating MCQ Quiz 9289 Ph2 Pt2

A customer has complained about lukewarm water coming from the cold tap. On close examination by an operative, it is clear that the hot water storage system is unvented. What is the cause of the problem and how would it be resolved?

• Back pressure has occurred because the check valve has failed, allowing the hot water to expand in the pipe. The check valve will need to be replaced.

• The expansion vessel is undersized, meaning that expansion must have taken place within the cold water system. A correctly sized expansion vessel will need to be installed.

• Back siphonage has occurred; this happens when the tap is opened too quickly, causing negative pressure. An anti-vac valve will need to be installed.

• The seating on the pressure release valve has become stuck, preventing pressure from leaving the system. The relief valve will need to be cleaned or replaced.

Which risk category permits only an air gap to act as protection against contaminating the mains water supply?

• Category 2

• Category 3

• Category 4

• Category 5

What backflow prevention should be used on a washbasin where the tap outlets are below the spillover level?

• Single check valve.

• Inline pipe interrupter.

• Reduced pressure zone.

• Double check valve.

What is a disadvantage of a gas-fired gravity hot water and pumped heating system?

• The heating cannot be operated independently from the hot water.

• The system requires a higher volume of water to operate hot water and heating efficiently.

• The hot water cannot be operated independently from the heating.

• The system lacks temperature controls which causes both hot water and heating to overheat.

What is the minimum size of pipework required on a pumped heating gravity hot water system?

• 15 mm heating primary flow and return with 22 mm pipework used for the gravity hot water cylinder.

• 22 mm heating primary flow and return with 22 mm pipework used for the gravity hot water cylinder.

• 22 mm heating primary flow and return with 28 mm pipework used for the gravity hot water cylinder.

• 28 mm heating primary flow and return with 22 mm pipework used for the gravity hot water cylinder.

What pipe sizes are used on a microbore system, including the size of the heating manifolds?

• 8 mm and 10 mm pipe connected to a 15 mm manifold.

• 10 mm and 15 mm pipe connected to a 15 mm manifold.

• 8 mm and 10 mm pipe connected to a 22 mm manifold.

• 10 mm and 15 mm pipe connected to a 22 mm manifold.

Which boiler incorporates a diverter valve and a plate heat exchanger?

• Back boiler.

• Combination boiler.

• Heat only boiler.

• System boiler.

Which component is included when installing a sealed central heating system?

• Feed and expansion cistern.

• Composite valve.

• Expansion vessel.

• Limiting valve.

What is the purpose of the component in Figure 3?

• Assist circulation in the heating system.

• Remove air from the heating system.

• Remove iron oxide from the heating system.

• Relieve pressure in the heating system.

A heating engineer is required to diagnose an issue with a fully pumped central heating system. The upstairs radiators and the hot water flow and return pipes to the upstairs hot water cylinder are lukewarm. The downstairs radiators are cold. What actions should be taken by the heating engineer, from start to end?

• Check circulation, by examining the pump. If power is present at the pump control box but the impellers are not rotating, carry out safe isolation and change the pump.

• Check the automatic bypass. If it fails to open to relieve pressure, drain the system and replace it. On completion, operate the system and carry out functional testing.

• Check the programmer by operating the thermostats. If power is not present at the thermostat to operate the system, carry out safe isolation and change the programmer.

• Check the water content in the system. If there's insufficient water in the system. Safely isolate the water supply and repair or replace the feed and expansion system.