INSTALLATION
SECTION 3
10
When installing Andrews Water H eaters in hard water areas we would recommend that a water
treatment specialist is consulted.
In hard water areas, scale formation can occur in all hot water systems and water heaters and the
higher the temperature and volume of water used, the more problematic the scale build-up can be.
Water treatment is normally recommended when the hardness reaches 100
–
150ppm (7
–
10
degrees Clark) and above. This problem can be minimised by reducing the water temperature in
the heater and by fitting suitable water pre-treatment equipment. It is for this reason we strongly
recommend water pre-treatment is fitted. A base-exchange type of softener is recommended for
a reliable solution to hard water. Also the tank should be inspected annually.
See page 36.
An unvented system must be fitted by an approved installer.
The pressure-reducing valve C1 will regulate the mains water pressure at 3.5 bar (provided there is
sufficient mains water pressure available). The maximum test pressure should be 8 bar. The
expansion vessel C3 supplied is suitable for the stored volume of the heater and a comparative pipe
work system. The temperature and pressure relief valve(s) are factory fitted. FOR SY STEM S WITH
LARGER PIPE V OLUM ES OR AD D ITION AL STORAGE, EX PAN SION V ESSELS WITH M ORE
CAPACITY ARE AV AILABLE.
We do not recommend the use of Galvanised pipework due to issues such as galvanic attack
(British Standard BS6644). The
has a number of copper and brass components.
C3
The cold water connection and the hot water connection can be found on the top of the
appliance, see Fig.1a and 1b. An extra connection is available for the benefit of a circulation line.
Please note that a stop valve should be fitted in the circulation line.
The
range of storage water heaters are designed to work from a mains fed unvented
system. An unvented kit to regulate the cold feed is supplied with each heater and should be
installed as Fig.1, 1a and 1b plus drawings on pages 5, 6 and 7.
The temperature and pressure relief valves are supplied factory fitted for external connection to a
tundish (supplied) and suitable drain. The
can also operate on vented systems providing
the minimum water pressure is one bar.
Condensation is formed in the heater and this must be continuously discharged into a drain. A trap
is supplied which should be connected into a drain via a tundish or air break. (See Fig.1a and 1b).
The condense flow must not be allowed to block otherwise the heater will fail to work correctly.
N OTE: AN AIR BREAK IS REQ UIRED D OWN STREAM OF TH E TRAP TO PROTECT TH E WATER
H EATER FROM BLOCK AGES AN D SUBSEQ UEN T D AM AGE. Each 30kw module could produce up
to 3 litres of condense per hour while at full load.
Th e Wa ll M o u n t in g
As s e m b ly C7 & C8
is a v a ila b le a s a n
o p t io n a l e x tr a
WATER
CONNECTIONS
CONDENSE DRAIN
WATER
QUALITY AND
TREATM ENT
Fig . 1
MAXXflo_Manual_Dec08_QX2 12/1/09 1:13 pm Page 13
Summary of Contents for CWH120/200
Page 43: ......
