5
Pipe Connections
16
5.3 domestic Hot Water
System
To maintain a longer and more
consistent hot water temperature,
a flow restrictor is factory fitted to
all models except the Vortex Pro
Combi 36e, to limit the flow rate to
approximately 15 litres / minute.
The flow restrictor is located in the
outlet side of the cold water inlet
isolating valve.
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 / minute.
To ensure economic use, the pipe runs
between the boiler and hot taps should
be as short as possible and in 15mm
copper pipe or 22mm for the Vortex
Pro Combi 36e only. Where possible
the pipework should be insulated to
reduce heat loss.
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.
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 25mm 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.
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 antisyphonage are
not necessary.
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
guarantee and any extended guarantee
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 guarantee.
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.
The mains water connection to the
boiler must be the first connection from
the mains supply.
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.
Do not immerse the test strip in
running water and avoid contact.
5.4 to use the Water
Hardness Kit
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.
!
CaUtiOn
!
nOtE
Green Areas
Violet Areas
Hardness
Total Hardness mg/l (ppm)
4
0
Very Soft
<50 mg/l calcium Carbonate
3
1
Soft
<70 mg/l calcium Carbonate
2
2
Medium
<125 mg/l calcium Carbonate
1
3
Hard
<250 mg/l calcium Carbonate
0
4
Very Hard
<370 mg/l calcium Carbonate
Note: (1 mg/l = 1 ppm (part per million)
