Page 522 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

The City & Guilds Textbook: Plumbing Book 1

l tasks that may require system drain down
l power flushing a system
l routine maintenance tasks
l dealing with simple system faults.
Whatever maintenance activity is being undertaken, safe isolation of the system
is paramount.

Replacing a central heating circulating pump,
step by step
You should attempt this task only under supervision. The system should not
require draining when replacing a pump.
Before attempting to remove the pump, the electricity should be isolated at the
switched fused spur and the fuse retained to prevent accidental switching on of
the circuit.
1 Check that the electrical circuit is dead using a GS38 proving unit or some
other effective electrical testing device.
2 Make a simple drawing of the live/neutral/earth connections on the pump
and disconnect the cable.
3 Turn off the isolating valves either side of the pump.
4 Carefully loosen the unions on the pump by turning them anti-clockwise
using water pump pliers. It may be a good idea to have some old towels
handy to catch any water.
5 Once both unions have been disconnected, remove the pump. The pump
unions should have the old washers removed and the union faces cleaned.
The new pump will include flat rubber washers in the box.
6 Position the new pump, with the sealing washers in place between the
valves, and hand tighten the unions. Take care to ensure that the pump is
facing the right direction for the system.
7 Fully tighten the unions with the water pump pliers. If the pump is installed
horizontally, make sure that the bleed point is slightly above horizontal as
this will help to remove any air in the pump.
8 Turn on the pump valves and check for leaks.
9 Carefully reconnect the electrics to the pump: live to the L point, neutral
to the N point and earth to the E point. Make sure that all electrical
connections are tight.
10 Remove the centre bleed point on the pump and release any air.
11 Reinstate the fuse in the consumer unit. Switch on and test for correct
operation.
12 With open vented systems, check the F and E cistern in the roof space to
ensure that the pump is not pumping water over the cistern through the
vent pipe.

Replacing a radiator, step by step
If the new radiator is the same size as the one being replaced, the pipework
should fit without too many problems. If the new radiator is either larger or
smaller, then the pipework will either have to be altered or a radiator valve

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