4.1 ANSWER SHEET 4.1 shows two incomplete drawings of an open and a closed non-return valve without the spring and ball in place - NSC Civil Technology Civil Services - Question 4 - 2020 - Paper 1

The primary function of the water meter is to enable local authorities to calculate the amount of water consumed by a household. This information is crucial for billing purposes and ensuring resource management.

Maintenance of the water meter is typically the responsibility of the local authority or water utility company, as they oversee its installation, calibration, and any necessary repairs.

Soil water refers to the water that is held in the spaces between soil particles. This water is crucial for plant growth as it provides the necessary moisture and nutrients that plants absorb through their roots.

The straight pan collar is used to join soil pipes at a 135° angle, facilitating a smooth transition in the direction of flow.

The T-junction is utilized to connect multiple pipes together at a 135° angle, allowing for a branch in plumbing systems.

The bend 135° fitting is designed to change the direction of a pipe run, ensuring that the flow continues smoothly at the specified angle.

A compressed-air test apparatus is commonly used to detect leakages in sewer pipes.

1. It does not require electricity, making it a cost-effective solution for reducing water consumption.
2. There are no ongoing costs associated with energy usage, which helps to save money.
3. It allows for a reduction in heat loss in recirculating pipes, leading to more efficient water heating.

A Johnson pipe coupling is often recommended for repairing leaks in galvanised steel pipes.

The components that are incorrectly installed are:

1. Pressure-reducing valve
2. Vacuum breaker

1. Move the pressure reducing valve next to the stop cock before the cold water draw off to other taps.
2. Install the two vacuum breakers in line with each other, ensuring a minimum distance of 300 mm between them.

The unit of the geyser that regulates the temperature of the water is the thermostat.

The anode protects the geyser from corrosion by attracting corrosive elements in the water, thereby prolonging the lifespan of the geyser.

A pipe-thread cutting machine is suitable for cutting galvanised steel pipes.

The tube used in the solar water heating system is referred to as an evacuated tube.

A - Outer glass tube/Glass B - Radiation absorbing coating C - Inner glass tube D - Fluid tube

A water pressure testing pump can be used to test the pressure of the water inside the solar water heating system.

Both processes involve the corrosion of materials, whereby an electrolytic reaction facilitates the degradation of metals in the presence of an electrolyte.

The type of corrosion illustrated is galvanic corrosion, which occurs when two different metals are electrically connected in the presence of an electrolyte.

A - Copper pipe B - Galvanised steel pipe

Using a drain cleaning machine requires less effort from the worker compared to drain cleaning rods because it is self-propelled and can navigate through pipes without manual force. Additionally, the machine is already fully assembled, making it easier to operate.

1. Regularly clean the bearing bracket to ensure there are no contaminants that may cause wear and tear.
2. Lubricate the bearings regularly to reduce friction and maintain smooth operation.