3B Components of Domestic Cold Water Systems

Components Used in Domestic Cold Water

• Domestic cold water systems use various components, including isolation valves, taps, and cold water storage cisterns.
• Different types of isolation valves are used for different purposes.
• Screw down stop valves are typically used on incoming mains (high pressure) and have a specific flow direction.
• Service valves (slotted) can handle high or low pressure and are placed before float operated valves on certain appliances, with a determined flow direction.
• Washing machine valves connect before washing machine hoses.
• Lever arm spherical plug valves handle high or low pressure, following a specific flow direction.
• Fullway gate valves function only with low pressure systems, similarly to other valves with lock shields to prevent tampering.

Lesson Intent

• Students will identify various components and describe the use of specific isolation valves.
• Students will be able to distinguish different tap types and write short descriptions.
• Students will provide a list of cold water storage cistern parts.
• Students will explain the differences between float-operated valves and their uses.

Legal Requirements

• UK plumbers are legally obligated to utilize approved materials, fittings, and appliances.
• WRAS (Water Regulations Approval Scheme) standards ensure that used products meet necessary safety, quality and performance standards.
• Approved products prevent backflow contamination and corrosion in water systems.

Isolation Valves

• Screw down stop valves: Employed on incoming mains, high-pressure systems, and have a stated flow direction.
• Service valves (slotted): Can operate with high or low pressure; they're typically fitted before float valves for specific appliances with a clear flow direction.
• Washing machine valves: These are installed prior to the washing machine hose attachment.

Isolation Valves (continued)

• Lever arm spherical plug valves: Suitable for high or low pressure, with a specific flow direction.
• Fullway gate valves: Specific to low-pressure systems, and like other valves, they can have lock shields to prevent tampering or misuse.

Activity 1: Labeling Valves

• Images show various valve types (washing machine valve, tap connector isolation valve, lever valve, fullway gate valve).
• Students should correctly identify and label each valve.

Surestop

• Surestop is a modern main isolation system.
• This system uses air/water pressure.
• A solenoid type system serves as an emergency isolation valve for possible leaks.
• A manual valve should be employed upstream in the system for component failures, and the system might be wired to a control system.

Surestop (continued)

• Brass stopcocks often are in inconvenient areas.
• Surestop remote stopcocks provide a simple method for turning off water up to two meters away.
• Easy installation and water pressure makes it effective.

Drain Off Valve

• Drain off valves should be installed at every low point of a water system.
• These valves are positioned directly above the incoming stop valve, permitting the safe removal of water.

Screw Down (high pressure) and Fullway (low pressure)

• Diagrams display the internal workings of both valves.
• Detailed explanations of components (e.g., tap wheel head, rising spindle, packing gland, packing, head workings, jumper and washer for screw down) can be found alongside descriptive labels for their respective components (e.g., wheel head, packing gland, packing, non-rising spindle, rising gate, and olive compression fitting for fullway).

Isolation Valves (Questions)

• Students can answer questions regarding types of isolation valves.
• Questions can include identification of screw-down stop valve, spherical plug valve, slotted service valve, and gate valve configurations.

Pillars Taps

• Pillar taps primarily serve baths, basins, and bidets.
• Baths use ¾" BSP tails with 22mm pipes.
• Basins and bidets use ½" BSP tails with 15 mm pipes.

High Neck Pillar Taps

• High neck pillar taps are specifically designed for use on kitchen sinks.
• Taps have a similar look to standard pillar taps, having a larger air gap provided via a longer neck.
• A ½" BSP tail is attached to a 15mm pipe for drainage/supply.

Bi-Flow Mixer Tap

• Known as a mono-block, bi-flow tap has two taps in a single body.
• A single spout divides water flow but allows for independent flow from either tap.
• They mix the water flow after leaving the taps only.
• These are designed for use on baths, basins, and bidets.

Mixer Tap

• True mixer taps combine hot and cold water within their body for mixing.
• They are suitable for sinks and baths where equal pressure from hot and cold sources is ideal.
• In specific circumstances, they can need specialized installation based on equal pressure system requirements.

Bib Taps

• Bib taps require a back plate elbow for wall-mounted installations.
• These taps are fitted over sink areas, and in some cases, the tap is outside.

Tap Types

• Taps are categorized into three main types, with varying configurations relating to the positioning of the spindle and handle.
• These three types contain a rising spindle tap, a non-rising spindle tap, and a quarter-turn tap.
• The identification, and in some cases a diagram, of the different components can be found in the respective sections above (spindle tap, non-rising tap, and quarter-turn tap).

Cold Water Storage Cistern

• Cold water storage cisterns must meet water regulation standards, offering wholesomeness, cleanliness, and prevention of contaminants.
• Piping and control mechanisms should be situated to prevent stagnation and offer accessibility for cleaning and maintenance, following manufacturer guidelines.

Cold Water Storage Cistern (continued)

• Cold water storage cisterns are made of materials such as plastic, fibreglass, asbestos, and galvanized steel.
• Cisterns should have a minimum of 350mm clearance above the top access point, facilitating maintenance.
• Cisterns under and over 1000 liters need either a single warning pipe or a separate warning/overflow pipe, ensuring there is an audible warning for any problems.

Drilling Cisterns

• Flexible cisterns need hole saws for drilling.
• Avoid heating copper pipes and using oil-based materials when working with plastic cisterns, as either of these can lead to leakage.

Multiple Cisterns

• Where two or more cisterns are interconnected, the water regulations and BS EN 806 state that all float operated valves and warning pipes should be in the same cistern.
• Stagnation issues are important factors to consider; if separate cisterns interconnect, a separate connecting pipe is necessary to the subsequent cistern.

Stagnation

• Stagnation is a potential issue in a single cistern.
• To avoid this problem, install the primary outlet on the opposite side to the float-operated valve for optimal flow and prevention of stagnant water.

Incorrect/Correct Cisterns

• Images depict scenarios with incorrect installations (e.g., issues with water pooling in cisterns below, lack of adequate support).
• Contrasting images suggest correct installations (e.g., well-supported cisterns in lofts with adequate spacing).

Float Operated Valves

• A float-operated valve shuts off the water supply to a cistern at a specified level.
• It operates on a lever system, where the valve opens when the float is in the lower position.
• As water fills the cistern, the float rises and slowly closes the valve.

Float Operated Valves (continued)

• Different types of float-operated valves (e.g., Portsmouth valve, diaphragm valve) are defined in given information.
• These different types have varying outlet configurations (bottom or top, depending on the design/type).

Water Hammer

• Water hammer is a common issue with water pipes that are subjected to high pressure.
• Some causes of water hammer include loose jumpers, improper pipe installation, and certain valve configurations.
• Specific types of water hammer problems arise from partially blocked valves or insufficient supports and stiffeners.

System Maintenance

• Maintaining valves is crucial for proper cistern functionality.
• Periodic inspections ensure the water levels are correct.
• Maintaining proper flow of water is vital to the efficiency and function of the plumbing system.

Test Your Knowledge (Questions)

• Questions covering the functionality and installation of diverse types of valves, taps, cisterns and other elements are included.
• Questions are provided about the function of the valve, its location, and its pressure requirements.

This quiz focuses on the various components used in domestic cold water systems, including isolation valves, taps, and storage cisterns. Students will learn to identify the functions of different types of valves and their applications in plumbing. Key concepts include flow direction and pressure handling.