4.1 Identify the water-heating system above - NSC Civil Technology Civil Services - Question 4 - 2019 - Paper 1

Continuous use of hot water from this system will result in the water temperature dropping as the geyser is unable to heat water continuously without sunlight, leading to colder water.

The glass panel must be cleaned regularly to ensure maximum operation efficiency. Dirt and debris can accumulate on the glass, blocking sunlight and reducing the system's heating capability.

An airlock is a pocket of trapped air within a pipe that prevents the normal flow of water. It can occur when the system isn't properly bled to remove air, leading to reduced water flow or complete blockage.

1. Sudden drops in secondary supply pipes can lead to pressure fluctuations, causing water hammer.
2. Pipes in walls are not properly secured to prevent movement when water flow is suddenly halted.

4.5.1:

4.5.2:

The type of water trap shown is an S-Trap, commonly used below sinks to prevent sewer gases from entering the living space.

The minimum diameter of the waste pipe that connects to the water trap is typically 40/50 mm.

A is a T Junction (Plain) and B is a 90-degree bend with an inspection eye.

A would be installed where soil pipes meet at a junction, while B would be used to change the direction of a soil pipe at a 90-degree angle.

A pipe-thread cutting machine can be used to effectively thread and cut pipes.

A water pressure testing pump is recommended for pressure testing of water systems.

A drain-cleaning machine, or jetting machine, can be used to clean and unblock drains using high water pressure.

The tap shown in FIGURE 4.11 is a pillar tap, commonly used for sinks and basins.

1. In the kitchen sink.
2. In the bathroom basin.

This fitting is called a water meter.

B is a full way valve, also known as a stop cock, which functions to turn off the water supply to prevent leaks or blockages.

The tap used at C is known as a bibcock or garden tap.

A chemical reaction will not take place if a high-density polyethylene pipe is connected to A.

This electrochemical reaction is known as dezincification.

1. Sensor taps that automatically shut off when not in use.
2. Demand pillar taps that only release water upon user demand.

A pressure-control valve is used to reduce/control the incoming water pressure to a building, while a temperature and pressure safety valve is designed to prevent excessive pressure buildup and protect the system from overheating.