Page 351 - 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

Repairing a BS 1212 Part 2 and 3 float-operated valve
(diaphragm type)
Diaphragm-type float-operated valves discharge water over the top of the valve.
They have a large diaphragm-type washer that is easily accessible for repair and
replacement. To replace the diaphragm washer, follow the steps listed below.
1 Turn off the water supply at the isolation valve to the float-operated valve.
2 Remove the float-operated valve from the cistern by unscrewing the union
nut.
3 Unscrew the large washer-retaining union and float arm arrangement at the
front of the valve, and withdraw the washer.
4 Replace the washer, ensuring that it is fitted the correct way. These washers
must be inserted correctly for the float-operated valve to operate as normal.
5 Replace the large washer-retaining union and float arm arrangement,
ensuring that is engaged into the retaining notch at the top of the front
plate and hand tighten the union.
6 Check that the orifice is in good order, with no cracks or splits. Replace as
necessary.
7 Re-install the valve into the cistern, making sure the fibre sealing washer is
in place.
8 Re-tighten the union and turn on the water.
9 Check the operation of the valve, adjusting the water level as necessary with
the float arm adjustment screw.

Replacing float-operated valves
Float-operated valves can be replaced easily, as the threaded connecting tail is
of a generic length, irrespective of manufacturer.
● Ensure that the water supply is isolated. Open the float-operated valve to
relieve the pressure and drain the pipework.
● Using an adjustable spanner, twist the float-operated valve locking nut
holding the float-operated valve to the cistern counter-clockwise half a
turn. This is to release the tap from the appliance. By not loosening the
tap connector first, the tap connector will prevent the float-operated valve
from spinning in the cistern.
● Attach the spanner to the tap connector and turn counter-clockwise,
ensuring that the float-operated valve is held firm by a pair of water
pump pliers.
● Remove the old float-operated valve.
● Take off the locking nut to the new float-operated valve and make sure that
the rubber grab washer is in place on the locking nut.
● Insert the float-operated valve into the cistern and wind up the new locking
nut clockwise by hand, then finally tighten with the tap spanner.
● Replace the fibre sealing washer on the tap connector and wind the tap
connector onto the float-operated valve. Tighten the tap connector.
● Turn on the water, check for leaks and test the float-operated valve.

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