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 eventually lead to the water getting cold, as the solar panel may not be able to heat the water consistently without sunlight.

The glass panel must be cleaned regularly to ensure maximum efficiency of the system. Dirt and debris can obstruct sunlight, reducing the heating performance.

An airlock is a condition in which air becomes trapped in a pipe and prevents the flow of water, leading to inefficiencies and possible disruptions in water delivery.

1. Sudden drop in pressure in secondary supply pipes.
2. Water pipe jumps in taps.
3. Pipes in walls are not properly caulked.
4. Pipes are not properly secured in roof spaces above the ceiling.
5. A draw-off pipe is bigger than the supply pipe.

4.5.1: A mixer with single manual control. 4.5.2: A vacuum relief valve combined with an air release valve.

The type of water trap shown in Figure 4.6 is an S-Trap.

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

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

A should be installed where the soil pipes with the same diameter meet. B should be installed above ground where soil pipes have to change direction at a 90-degree angle.

4.8.1: A pipe-thread cutting machine can be used to thread and cut pipes. 4.8.2: A water pressure testing pump can be used for pressure testing of water systems. 4.8.3: 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 identified as a pillar tap.

This tap can be used at:

1. Sinks in the kitchen.
2. Baths or bathrooms.

The fitting used to determine the water usage is called a water meter.

Fitting B is a full way valve or stop cock, and its function is to shut off the water supply.

The type of tap used at C is a bibcock, often referred to as a garden tap.

No chemical reaction will take place if a high-density polyethylene pipe is connected to A.

The electrochemical reaction that occurs when zinc is selectively leached from a copper pipe is known as dezincification.

1. Sensor taps that automatically turn off the flow of water.
2. Metered taps that charge users based on their water usage.

A pressure-control valve reduces and controls the incoming water pressure to a building. A temperature and pressure safety valve reduces the temperature and pressure within a water system in case of excessive pressure building up in the geyser.