IDEAL HE15 Installation And Servicing page 11

5 LOW HEAD AND LARGE SYSTEMS WITH EXTENSIVE PIPE RUNS - OPEN VENT
This arrangement is useful for large systems where
radiators at the extremities are difficult to vent. This
can lead to pumping over with conventional feed and
vent arrangements.
The following conditions MUST be observed:
1. The top of the automatic air vent must be below
the cold water level.
2. The static water level (cold) must be at least
200mm above the top of the horizontal flow pipe,
fitted as shown. The vent connection MUST NOT
be made immediately off the top of the boiler as
venting is made less efficient.
3. The maximum practical length of 22mm cold feed
pipe should be used in order to reduce the
effective volume of hot system water expanding
into the feed/expansion cistern to a minimum.
Note. The pump manufacturers' minimum requirements must be complied with.
6 SEALED SYSTEM REQUIREMENTS
Notes.
a. The method of filling, refilling, topping up or flushing
sealed primary hot water circuit from the mains via a
temporary hose connection is only allowed if
acceptable to the local water
authority.
b. When installing the filling device, it
must be connected as shown to
fully comply with the water
regulations. This may involve the
fitting of an additional WRAS
approval isolator valve to the
mains supply.
1. General
a. The installation must comply with the
requirements of BS. 6798 and BS. 5449.
b. The installation should be designed to work with
flow temperatures of up to 82
c. All components of the system, including the heat
exchanger of the indirect cylinder, must be
suitable for a working pressure of 3 bar (45lb/in
and temperature of 110
in making all connections so that the risk of
leakage is minimised.
2. Safety Valve
A spring loaded safety valve complying with the
relevant requirements of BS. 6759 must be fitted in
the flow pipe as close to the boiler as possible and
with no intervening valve or restriction. The valve
should have the following features:
mexico HE -
Installation & Servicing
GENERAL
C.
o
)
2
o
C. Care should be taken
cla7649
Flow Return
Temporary hose
a. A non-adjustable preset lift pressure not exceeding
3bar (45lb/in
b. A manual testing device.
c. Provision for connection of a discharge pipe.
The valve or discharge pipe should be positioned so
that the discharge of water or steam cannot create a
hazard to the occupants of the premises or cause
damage to electrical components and wiring.
3. Pressure Gauge
A pressure gauge covering at least the range 0-4 bar
(0-60 lb/in ) must be fitted to the system. The gauge
2
should be easily seen from the filling point and should
preferably be connected at the same point as the
expansion vessel.
All dimensions in mm (in.).
NB. Imperial dimensions are approximate
Non-return
valve
Automatic
air vent
Hosepipe
(disconnect
after filling)
Hose unions
Additional
stop valve
(disconnect
Double check valve
after filling)
assembly
(note direction of flow)
).
2
Hose
connector
11