Page 345 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 5 Cold water systems

VALUES AND BEHAVIOURS

Do not forget to keep the householder/responsible person informed of the
areas that are going to be isolated during maintenance tasks and operations,
and always ask the customer if they need to ‘draw off’ a temporary supply
of water (kettle, saucepans, bucket, etc.) to cover a short period of system
isolation.

Unplanned and emergency maintenance
Unplanned and emergency maintenance occur when a fault suddenly develops,
such as a burst pipe, or a small problem suddenly becomes a larger issue, such as
a dripping tap or sudden loss of water. Unplanned and emergency maintenance
can include:

● burst pipes and leaks
● running overflows
● dripping taps
● loss of low-pressure, cistern-fed cold water supply due to faulty float-operated
valves
● poor past installation practices, such as incorrectly positioned overflow pipes
● complete component breakdown necessitating the replacement of the
component.

Many of the maintenance practices we use involve the decommissioning
of systems so that parts and pipes can be replaced.

Maintenance tasks

In this part of the chapter, we will look at some of the basic maintenance tasks
we have to perform, including:

● re-washering and re-seating a BS 1010 tap
● re-washering a BS 5412 tap
● maintaining a ceramic disc tap
● maintaining a BS 1212 Part 1 float-operated valve
● maintaining BS 1212 Part 2 and 3 float-operated valves.
Re-washering and re-seating a BS 1010 rising spindle tap

BS 1010 taps are probably the easiest of all taps that we have to maintain. During
the maintenance operation, taps should be re-seated as well as re-washered. This
involves using a special tool, called a tap re-seating tool, which grinds the seat of
the tap to remove any pits that have occurred due to water passing between the
seat and the tap, ensuring that the washer sits evenly on the tap seat.
The procedure for re-washering a BS 1010 tap is as follows. p Figure 5.120 Tap re-seating tool
First, ensure that the water supply is isolated, open the tap to relieve the pressure
and put the plug into the sink. This will ensure that any dropped small screws and
nuts do not disappear down the sink waste and into the waste pipe trap.

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