Water Connections; Open Vent Design - Potterton iHE 100 Installation & Servicing Instructions Manual

2.3 WATER CONNECTIONS

G
ENERAL
The cold water inlet and hot water outlet connection
nipples are identifi ed on top of the appliance.
Connect the cold water feed and hot water outlet
to these nipples with union adaptors for ease of
servicing. Connect the supplied isolating valve to
the drain connection and pipe to a suitable discharge
point.
(See fi g 1.1 for connection locations)
Do not apply excessive torque to these
nipples when making connections. The
use of an appropriate pipe sealing
compound s recommended
C W S - S
OLD ATER UPPLY YSTEM
The appliance may be connected to an open vent or
sealed system supply. When connected to a sealed
system an unvented water kit must be installed with
a minimum water pressure of one bar. The appliances
are factory fi tted with temperature and pressure
relief valves. An unvented system must be fi tted by
an approved installer.
Cold Water Supply - Quality and Treatment
In hard water areas scale formation can occur in all
hot water systems and the higher the volume and
hotter the water used, the greater and more prob-
lematic the scale build-up can be. Water treatment
is usually recommended when the hardness levels
measures greater than 150 ppm. For this reason,
base exchange water treatment is strongly recom-
mended in hard water areas.

2.4 OPEN VENT DESIGN

The tank must be supplied from a cold water feed
cistern and the hot water supply pipe must be fi tted
with an open vent pipe in accordance with BS 5546
and BS 6644. The Water Supply (Water Fittings)
Regulations must be observed when installing the
system.
The cold water feed cistern must have an actual
capacity greater than the hourly recovery rate of the
heater or heaters to which it is fi tted, the minimum
actual capacity allowed for a feed cistern being 227
litres (50 gallons).
The actual cistern capacity is the capacity to the
normal water level of the cistern. All cisterns should
be manufactured to the relevant Standard.
The distance from the normal water level to the top
of the cistern should comply with that specifi ed by
the Water Authorities.
iHE
S R
(F 2.5)
ECONDARY ETURN
IG
A Secondary Return circuit may be fi tted to the 1"
nipple at the top of the appliance. In all cases, for
serviceability, the recirculation pipe must be fi tted
with a stop valve immediately before the connec-
tion point.
D -S
E TRATIFICATION
By virtue of its design an internal DHW tank de-
stratifi cation pump is not required.
iHE OPEN VENT EXAMPLE
Service Valve
Drain
9
Outlets
Pump
T&P Valve Outlets
Fig 2.3
GB/IE