6 Domestic Cold Water Systems Maintenance

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.)