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Maintenance

Maintenance

7.1 Servicing and Maintenance

1. Servicing and maintenance must

only be carried out by a competent
unvented hot water installer, or by
Grant Engineering (UK) Limited
authorised personnel.

2. Before any work whatsoever is

carried out on the installation, it
MUST first be isolated from the
main’s electricity supply.

Both the primary and secondary
systems will contain very hot water
that will scald; therefore care should
be taken when opening any joints,
seals or valves.

3. Only use spare parts authorised by

Grant Engineering (UK) Limited. The
use of unauthorised spare parts will
invalidate the warranty.

4. Drain the cylinder – When draining

the cylinder, always switch off the
boiler and the immersion heater
first. Turn off the water supply at the
mains stopcock.

Connect a hose pipe to the drain
cock (see Figures 2-4 to 2-6) and
route it to a convenient gully. Open
the drain cock and all hot taps that
are served by the cylinder. The
cylinder may take several minutes to
empty completely.

5. In hard water areas it may be

necessary from time to time to
remove and de-scale the immersion
heater element. Replace the gasket
each time it is removed.

6. Remove the cartridge from the

pressure-reducing valve (PRV).
Check the strainer and if necessary
remove any debris from in front of
it. Replace the cartridge. Refer to
section 7.3 on the right.

7. Check the charge pressure in the

expansion vessel and top up as
necessary. The charge pressure
should be 3.0bar. Refer to section
7.5 on the right.

WARNING

8. Whilst the hose pipe is connected, the

drain cock open and with the
immersion heater removed, the
cylinder may be flushed out to remove
any debris, sand or lime scale particles
that may have collected in the bottom
by using a further hose pipe
connected to the cold water main.

9. Close the drain cock, disconnect

the hose, refit the immersion heater
and close all hot water taps before
reopening the stopcock. Allow the
cylinder time to fill whilst checking
for any leaks. Release any air from
the system by opening each hot
water tap individually, starting with
the one furthest from the cylinder.

10. Manually lift the expansion relief and

temperature and pressure relief
valve one at a time, every 12
months (more frequently in hard
water areas) to prevent debris from
building up behind the valve seat.
Whilst carrying out this operation,
check that the discharge to waste
is unobstructed. Check that each
valve seals correctly when released.
As the valves are pre-calibrated,
they require no further maintenance.

11. Finally switch on the mains

electricity supply to the immersion
heater and the boiler. As the system
heats up, check again for any leaks
and rectify as necessary.

7.2 Manifold Assembly

The manifold assembly should not,
under normal circumstance, require any
maintenance. During annual servicing it
may be necessary to inspect and/or
clean the line strainer, the pressure
reducing valve cartridge, expansion
relief valve cartridge. The frequency of
cleaning will depend on the local water
conditions.

7.3 Pressure Reducing Valve

1. Isolate the cold water supply.

2. Unscrew the retaining nut of the

valve. The complete operating
mechanism, including the strainer
can be removed.

3. Clean the filter mesh and the

cartridge under running water.

4. Replace cartridge ensuring that

strainer is correctly located and
reassemble the unit. Pressure
Reducing Valve cartridge and
strainer Part No. GCS07C - 3.0 bar.

7.4 Expansion Relief Valve
Cartridge

1. Isolate the cold water supply.

2. Remove grub screw (Allen Key

type) from body of valve and
withdraw valve ensuring not to
damage O-ring.