Page 352 - 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

Replacing pumps in boosting sets
When replacing any electrical component, first ensure that the electricity
supply is totally isolated by initiating the safe isolation procedure for electricity
supplies, as follows.
l Remove the fuse from the consumer unit.
● Check that the electrical circuit is dead using a GS38 tester and proving unit
or some other effective electrical testing device.
● Make a simple drawing of the live/neutral/earth connections on the pump
and disconnect the cable.
● Turn off the isolating valves on the inlet and outlet to the pump.
● 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.
● 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 should include flat rubber washers.
● 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 in the right direction for the system.
● Fully tighten the unions with the water pump pliers.
● Turn on the pump valves and check for leaks.
● 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.
● Reinstate the fuse in the consumer unit. Switch on and test for correct
operation.

12 DECOMMISSIONING

OF SYSTEMS

Occasionally, systems will require isolation for repairs, renewal of appliances
and extensions to systems, or when systems or appliances are being
permanently removed. This is known as decommissioning. Decommissioning
takes two forms:
1 Temporary decommissioning: this is where systems are isolated for a
period of time so that work can be performed. Eventually, the system will be
recommissioned and put back into normal operation.
2 Permanent decommissioning: when a system or an appliance is taken out
of use, it has to be permanently decommissioned. This will require that the
system is isolated and drained, the appliance(s) removed, and the pipework
cut back, removed and capped to the nearest live line to prevent stagnation
of water in a live cold water supply.

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