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Fig. 6. System filling and make-up.
Heating Return
Non return
valve
+-
Non return
valve
~
Hose
un1on
l
t--...y<llt--r--{..-0..--.. ----,
,.
~
See Fig. 7
!J
f!
Stop cock
::eo==~/'
Test cock
Temporary hose
9.
OPEN VENT PRIMARY
SYSTEM
1.
For sizes of flow and return pipework refer to Section 2-
Technical Data and Fig_ 2
2.
FEED AND EXPANSION CISTERN
The feed and expansion pipe must rise continuously from the
appliance avoiding any horizontal runs.
The cistern must be arranged to provide a minimum static
head of 1 metre (39 in.} above the top of the appliance or above
the highest point in the heating circuit whichever is the greater.
3.
SAFETY VALVE
A safety valve is not required on an open vented system. If
preferred. it may be removed from the appliance and the
tapping blanked off. If the valve is left in position, a discharge
pipe must be fitted which terminates in a position such that if
water or steam is discharged it would not cause a hazard to the
occupants of the premises or damage the electrical com-
ponents and wiring. See Fig. 5
Fig. 7 _ Open vent water system.
EXPANSION
TANK
4.
Heating Return
Auto
air vent
..... ....., .... _
Fill Point
'
Heating Return
FILLING AND VENTING
300mm 112m) min.
above the highest
pomt of the system
An auto air vent {which initially requires the top to be loosened)
is fitted to the top of the insulated heat exchanger adjacent to
the boiler. See Fig. 29. Air should be released as necessary from
this point during filling. Any other air within the appliance will
be expelled via the feed and vent connection or dissipated into
the rest of the system. The heating system should be fitted with
manual air vents at any high point
5.
SYSTEM BY-PASS
A suitable by-pass must be fitted, designed to give the
minimum flow rate indicated in Table 3 corresponding to the
heating output used. A suitable position for the by-pass is
shown in Fig. 5_ The by-pass should be connected in 22 mm
diameter pipe at least 2 metres (7ft.) from the appliance and
fitted with a suitable valve to provide adjustment.
To adjust the by·pass, the boiler should be operated on central
heating with the by-pass and radiator valves set fully open for
at least 45 minutes. With the aid of a contact thermometer,
balance the heating system and restrict the by-pass by the
minimum amount
necessar~
to give a temperature rise across
the flow and return pipes of 11
°( (20°F)
6.
PUMP
The central heating pump has been set at MAXIMUM and
must not be adjusted
DOMESTIC COLD WATER
TOT APS. SHOWER
h
ANDWC
- - - - - - -
1"-~~~-="t----
- - -
- j - - -
T-
- -
-,
I
STATIC
HEAD
L_
- r--------.,
,.--------.,
,J llllllll,
.J
1111111 L
1..-------..1
I
'
._
_______
...
'
~
* *
*
--- i--- --- _____
...~__
-T---- ______
_.L ___ - •
I
I
I
--~---------------L-------------,
I
I
I
NOTE: A DRAIN COCK S'lOULD BE
I
INSTALLED AT THE LOWEST
I
POINT Of THE SYSTEM AND
I
BENEATH THE BOILER.
I
I
I
I
I
I
Jlllllll
II
II;:;~~
I
I
I
l
I
I
LOCKSHIELD
I
VALVE
'
SPHERICAL PLUG BAll
VALVE
FORA~ANCE
COMBINED
SERVICING
\:-,.
FEED AND
VENT
~
~--2m171t1MIN.--
-,
I
HEATING RETURN
:
I
HEATING HOW
I
I
I
l
I
r-
BRITISH STANDARD
STOP VALVE FIXED
SPINDLE TYPE
I
MAIN
DOMESTIC
HOT
WATER
- - - - -
I
I
I
I
~-t
I
lfl ll
AUTOMATIC
MINIMUM ST A Tl CHEADTOBE 1m
FROM THE TOP
I
I I
AIR VENT
I
HOW RESTRICTORS
BOILER
•
HEAT
:;;
BANK
~
-~
~
PRESSUR£
J.
EXPA;SION
~~
~
GAUGE
VESSEL
APPLIANCE
CASING
9
13ft) MEASURED
SURFACE OF TH E APPLIANCE OR
OINT IN THE
THE HIGHEST P
HEATING SYSTE M TO THE TOP OF
EL IN THE FEED
NTANK
THE WATER LEV
AND EXPANSIO
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