7
221899A
Diagram 3.1
2.3 Terminal Guard
A terminal guard is required if persons could come into contact
with the terminal or the terminal could be subject to damage.
If a terminal guard is required, it must be positioned to provide
a minimum of 50mm clearance from any part of the terminal and
be central over the terminal, see diagram 2.2.
A suitable guard, reference Type “K3”, can be obtained from:
Tower Flue Components Ltd.,
Morley Road, Tonbridge,
Kent. TN9 1RA
Diagram 2.2
7056
The installation of the boiler must comply with the requirements
of the current issue of BS6798.
3.1 Frost Protection
There is a built-in frost stat in this boiler. See Protection Against
Freezing in Instructions for Use. Where other parts of the
system are vulnerable this should also be considered as specified
in the current issue of BS5422.
3.2 Pump
The pump, with integral valves, should be fitted in the heating
flow pipework from the boiler, it should be set to produce a
temperature difference of 11
o
C (20
o
F), between the flow and
return, with the boiler thermostat set at “MAX”, which is about
82
o
C (180
o
F).
The pressure loss of the boiler at 15.3 litre/minute giving 11
o
C
temperature difference is 150mm head of water.
High resistance microbore systems may require a higher duty
pump.
3.3 Bypass
A bypass is unnecessary, unless thermostatic radiator valves
are fitted to all radiators.
If required, a 15mm bypass must be fitted at least 2m away from
the boiler and adjusted such that there is a temperature difference
no greater than 20
0
C between flow and return.
3.4 Water System
For an open vented system the boiler must be supplied from an
unrestricted water supply taken from a feed and expansion
cistern fitted at a maximum height of 27 metres above the boiler.
The cold feed must be 15mm minimum size.
It is important that the relative positions of the pump, cold feed
and open vent are as shown in diagram 3.1.
The unrestricted open vent from the boiler must rise continuously
to discharge over the feed and expansion cistern.
3.5 Domestic Hot Water System
General. The domestic hot water service must be in accordance
with the current issue of BS5546, refer also to the current issue
of BS6700.
3.6 Cylinder
For all systems supplying domestic hot water the cylinder must
be indirect. It is recommended that the cylinder be fitted with
some form of temperature control.
3.7 Open Vented Fully Pumped Heating and
Domestic Hot Water
The connections for the system MUST be as shown in diagrams
3.1 and 3.2.
3.8 Inhibitor
Attention is drawn to the current issue of BS5449 and BS7593
on the use of inhibitors in central heating systems.
When installing in an existing system take special care to drain
the entire system, including radiators, then thoroughly cleaning
out before installing the boiler whether or not adding an inhibitor.
2 Flue and Ventilation
3 Water Systems
7065
FEED AND
EXPANSION
CISTERN
22mm VENT
(MIN.)
15mm (MINIMUM)
COLD FEED
OPEN VENTED FULLY PUMPED WATER SYSTEM
RECOMMENDED RELATIONSHIP BETWEEN
PUMP COLD FEED AND VENT
450mm
MIN.
HEIGHT
1METRE
MIN.
RETURN
FLOW
CYLINDER
PUMP
HEATING
150mm
MAX.
BOILER
IF REQUIRED
15mm (MINIMUM)
BY-PASS WITH
LOCKSHIELD VALVE
FLOW
RET.
There must
always be a cold
water path to the
return connection
of the boiler.
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