To Use The Water Hardness Kit - Grant Combi 70 V3 User's Installation Manual

5.13 Domestic hot water system
1 To maintain a longer and more consistent hot water
temperature, a flow restrictor is factory fitted to all
models except the Combi Max and Vortex Combi
36, to limit the flow rate to approximately 15 litres/
min. The flow restrictor is located in the outlet side
of the cold water inlet isolating valve.
2 The incoming mains water pressure should be
between 1 and 8 bar to ensure efficient operation.
If the pressure is above 8 bar a pressure reducing
valve must be fitted.
The boiler may still operate down to a pressure of
1.0 bar but with a reduced flow rate. The minimum
flow rate needed for the flow switch to operate is 3
litres/min.
3 To ensure economic use, the pipe runs between the
boiler and hot taps should be as short as possible
and in 15 mm copper pipe or 22 mm for the Combi
Max and Vortex Combi 36 only. Where possible
the pipework should be insulated to reduce heat
loss.
4 All taps and mixing valves used in the domestic hot
water system must be suitable for operating at a
mains pressure of up to 8 bar.
5 If required, a shower may be fitted in the domestic hot
water system. It is recommended that thermostatically
controlled shower valves are used to protect against a
flow of water at too high a temperature. If a fixed
head type shower is used, no anti-syphonage devices
are required. If a loose or flexible head type shower is
used, it must be arranged so that the head cannot fall
closer than 25 mm above the top of the bath, thereby
preventing immersion in the bath water. If this is not
practicable, an anti-syphonage device must be fitted
at the point of the flexible hose connection.
6 The supply of hot and cold mains water direct to a
bidet is allowed (subject to local Water
Undertaking requirements) provided that the bidet
is of the over-rim flushing type. The outlets should
be shrouded and unable to have a temporary hand
held spray attached. Arrangements for anti-
syphonage are not necessary.
7 Before the mains water supply pipe is connected to the
boiler, it should be thoroughly flushed out to avoid the
danger of dirt or foreign matter entering the boiler.
8 The mains water connection to the boiler must be
the first connection from the mains supply.
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5 - GENERAL BOILER INFORMATION
Combi V3, Combi Max and Vortex Combi models
Note: Hard Water
A water hardness test kit is supplied with the
boiler. Should the total hardness of the water
supply exceed 125 ppm, an in-line scale inhibitor
should be fitted in the cold water supply to the
boiler. Consult the local Water Undertaking if in
doubt.

To use the water hardness kit

5.14
Important: Do not immerse the test strip in running
water and avoid contact.
Fill a clean container with a sample of water from the
mains cold water supply to the boiler.
Immerse the test strip in the water for approximately
one second, ensuring that all the test zones are fully
wetted.
Shake off the surplus water and wait for one minute.
Assess the colouration of the test zones using the
following chart.
Green areas Violet areas Hardness
4 0 very soft
3 1
2 2 medium
1 3 hard
0 4 very hard
Note: (1 mg/l = 1 ppm (part per million)
If the hardness reading is found to be in the medium to
very hard range (the shaded area), it is essential that some
form of water conditioner or softener is fitted to reduce
scale formation within the combination boiler. Failure to
do so may invalidate both the manufacturers warranty
and any extended warranty covering the appliance.
The water conditioner or softener should be fitted to
the cold water supply serving the appliance and in
accordance with the manufacturers instructions. Grant
Engineering (UK) Ltd. cannot be held responsible for
any damage or misuse caused by the fitting of any
water conditioning device.
Please protect the domestic hot water system from
harmful effects of scale.
Problems caused by the build-up of limescale are
not covered under the terms of the warranty.
Total hardness mg/l (ppm)
<50 mg/l calcium carbonate
soft >70 mg/l calcium carbonate
>125 mg/l calcium carbonate
>250 mg/l calcium carbonate
>370 mg/l calcium carbonate