6 Domestic Cold Water Systems Maintenance

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Questions and Answers

What is one possible consequence of a component constantly vibrating due to water flow?

Loosening of connecting nuts (correct)

Reduction in water temperature

Improvement in flow rate

Increased water pressure

What typically indicates a blockage in the pipework?

Decreased flow rate noticed by the customer (correct)

Absence of air locks in the system

Increased water pressure readings

Sudden spike in water temperature

Which condition is likely to occur in low pressure systems?

Overflowing cisterns

Improved flow rates

Consistent water pressure

Increased air locks (correct)

What is a recommended practice when conducting planned preventative maintenance?

Consult maintenance instruction sheets before servicing Signup and view all the answers

What should be checked before installing any appliances?

Incoming pressure and flow rates Signup and view all the answers

What could cause a burst pipe in a plumbing system?

Low incoming pressure Signup and view all the answers

What is NOT a common issue listed under unplanned emergencies?

Temporary decrease in water usage Signup and view all the answers

Which factor can contribute to blockage in pipework?

Small diameter pipe fittings Signup and view all the answers

What is the recommended tool to address a defective tap seating that causes dripping from the outlet?

Re-seating tool or replace the whole tap Signup and view all the answers

What symptom might indicate that the water is letting by a gate valve?

Water still coming past the shut-off point Signup and view all the answers

Which of these situations could lead to air locks in a low pressure system?

Insecure pipework creating high and low spots Signup and view all the answers

In the case of a dripping tap caused by worn or broken washers, what must be done?

Replace the washer correctly Signup and view all the answers

What should be done when a tap is dripping from its body rather than the outlet?

Undo the cover and check the washer Signup and view all the answers

What is the common cause of ceramic disc failure in quarter turn taps?

Broken discs or damaged body Signup and view all the answers

What could be a potential cause of water hammer in a plumbing system?

Surges of pressure causing knocking noises Signup and view all the answers

How should one handle a jammed headgear in water fixtures?

Try to release it without damaging Signup and view all the answers

What should be used to lubricate jammed headgear in a tap?

Silicon grease Signup and view all the answers

When a tap is dripping from its body, what does this indicate?

Damaged washer joining the body Signup and view all the answers

What is a common fault that can lead to a valve letting by water?

Damaged sealing washer Signup and view all the answers

What outcome may occur from loose components in a plumbing system?

Leaking or additional system noise Signup and view all the answers

Which issue is typically associated with water hammer in a plumbing system?

Surges of pressure causing knocking noises Signup and view all the answers

What should be done if a ceramic disc in a tap is found to be leaking?

Replace the disc or the tap body Signup and view all the answers

What might indicate that air is trapped in a plumbing system?

Inconsistent water flow and noise Signup and view all the answers

What is typically the result of jammed headgear in a tap?

Inability to release the tap handle Signup and view all the answers

What can cause debris to block pipework?

Over-soldering or hemp use Signup and view all the answers

What is the typical effect of an incorrectly sized pipework on appliance performance?

Reduced water pressure Signup and view all the answers

What maintenance is essential for preventing leaks and ensuring functionality in a plumbing system?

Planned preventative maintenance (PPM) Signup and view all the answers

What could indicate that a water supply is at risk of an air lock?

Water spluttering from outlets Signup and view all the answers

Which action should be taken when isolating a plumbing system?

Label the system and notify users Signup and view all the answers

What is a common unplanned emergency that can occur in a plumbing system?

Poor installations Signup and view all the answers

What situation could result from low incoming pressure in a plumbing system?

Inefficient water flow in toilets Signup and view all the answers

What is one recommended action before installing any appliances?

Test pressure and flow rates Signup and view all the answers

Study Notes

Basic Maintenance Requirements of Domestic Cold Water Systems

Lesson Intent: Learners will be able to fault find and diagnose failures, identify and use specialist tools for routine maintenance, and create a list for temporarily decommissioning a cold water system for repair.

Worn or Broken Washers

Washers can be damaged in taps (or fixtures) and the outcome is dripping from an outlet.
Replacement of washers is essential and correct replacement techniques are important.
To prevent scratching chrome or gold fixtures, use soft-jaw pliers.

Defective Tap Seating

Dripping taps from the outlet or overflow indicate a defective tap seating.
A re-seating tool can be used, or the entire tap replaced if severely damaged.

Jammed Headgear

Sometimes, the headgear gets jammed in function and needs to be released.
Gently work on removing the jam, avoid rounding the nut.
Silicon grease is used for lubrication.
In cases of severe issues, replace the entire unit.

Dripping from Body

If a tap drips from the body rather than the outlet, the fibre/rubber washer joint connecting the body is likely damaged.
Identify the damage by undoing the cover.

Dripping from the Head

Problems with this type of dripping come from the packing glands in rising sple or O rings on non-rising sple, therefore requiring re-packing or replacement.
This issue can be mistaken for a washer fault on the body.

Letting By

Letting by is a term for a valve that allows water flow even when shut off.
This can affect:
- Taps — damaged washer/dripping
- Faucets — damaged washer/warning pipe
- Dripping
- Gate Valves — water still past
- Stop Valves — water still past

Ceramic Disc Failure

Quarter-turn taps dripping from the outlet may indicate a ceramic disc failure.
Replacing the discs, and in more extensive situations, the entire body are often the solutions.

Insecure Pipework

Insecure pipework creates high/low pressure spots (air locks and debris) in the plumbing system.
Pipe types:
- Plastic pipe
- Copper pipe
- LCS pipe
Issues like water hammer (pressure surges) and water murmur (pressure surges causing fast on/off of faucets) can arise.

Air in System

Air in the system can cause additional system noise as the air moves around the pipework or gets trapped in the pump, leading to aeration issues.
In severe situations, air locks can happen in pipework, particularly in low-pressure systems (high spots).

Loose Components

Loose components cause leaks or additional noise (if internal).
A loose fixture can detach and damage connecting pipework, creating a leak.
Components that vibrate from water flow can loosen nuts.
Broken clips need to be replaced.

Underground Bursts

Major bursts can significantly disrupt systems.
Damage determination occurs based on the location of the burst—inside or outside the property. Damage outside is often indicated by water discoloration (e.g., green).
Emergency response involves isolating the water supply at the incoming stop valve, isolating the whole house, and locating the meter outside.

Blockages

Blockages arise from debris left in pipework not fully flushed.
This debris gets caught in components, partially blocking the pipes (fixtures).
Potential blockage issues:
- limescale (shower rose)
- over-soldering or hemp
- valves not fully open.
A customer may notice a decrease in water flow, leading to a slow refill rate for kettles.

Incorrectly Sized Components

Wrongly sized pipework impacts the flow rate of water to appliances if too small.
Potential issues concerning sizes in piping:
- Fullway HP spherical plug valve
- Incorrect orifice in the fixture
- Fixtures produced for high-pressure systems only.
Proper pipework sizing is needed to guarantee appropriate flow rate and pressure at each outlet at Level 3.

Air Locks

Air locks occur in low-pressure systems. Improper pipework leaving high spots can trigger air locks in the system.
Scenarios:
- Spluttering water
- No water at the outcome

Low Incoming Pressure

Low incoming pressure can result in certain appliances not working correctly (combination boilers at 1 bar).
Before appliance installation, always test pressure and flow rates near the water supply.

Planned Preventative Maintenance (PPM)

PPM is used in large or commercial water systems to allow for pre-arranged maintenance schedules.
Planned maintenance may happen outside of standard business hours.
PPM focuses on preventing problems, including leaks, by:
- re-washering
- inspecting terminals & valves
- inspecting and cleaning cisterns (storage tanks)
- cleaning filters & strainers
- inspecting water softeners
- inspecting water levels

Planned Preventative Maintenance (PPM) — Additional Actions

Label the system if any isolation is needed and also, do not turn the valve on once it's been turned off.
Maintain records of pressure, flow rate, and temperatures.
Consult the maintenance service log for any repairs done.
Keep the customer informed of all maintenance progress.

Unplanned Emergencies

Unplanned emergencies can sometimes occur and include:
- Burst pipes
- Running overflows
- Dripping taps
- Low pressure in systems
- CWCS drying up (water heaters)
- Poor installations

Check Your Knowledge Questions

What tools are used for tap re-seating? (A re-seating tool is specifically mentioned.)
What plumbing issues could cause taps to drip from the body? (The fibre/rubber washer joint connecting the body is a likely cause, identified by undoing the cover.)
What does "letting by" mean in a plumbing context? (A valve allowing water flow even when shut off.)
What is PPM? (Planned Preventative Maintenance used in larger systems.)
Provide an example of an unplanned emergency. (A burst pipe is a good example.)

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Description

This quiz covers the basic maintenance requirements of domestic cold water systems, focusing on fault finding, diagnosing failures, and using the appropriate tools for routine maintenance. Participants will learn about common issues such as worn washers, defective tap seating, and jammed headgear, along with techniques for repairs.