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221834B
Diagram 2.1
Diagram 2.2
Design Minimum
Flow Rate Flow Rate
1.5
1.0
0.5
0
50
40
30
20
0
0
5
10 15
20 25 30
Flow rate
(
litres/minute
)
Water pressure loss
(metres head of water)
Water pressure loss
(inches head of water)
10
60
01
2
3
4
56
Flow rate (gallons/minute)
35 40
70
78
2.0
0164M
TABLE 3
BOILER
DRAIN
POINT
Energysaver 40
15.5L/min 11L/m
4042
2 Water System
Note.
The boiler has 28mm copper connections, which can be
reduced to 22mm for the Energysaver 40, provided the system
resistance does not exceed the chosen pump duty.
2.1 Draining Tap
The boiler is provided with a draining point at the lower left hand
side of the burner manifold, to be used for draining the boiler,
see diagram 2.1.
A draining tap must be provided at the lowest points of the
system which will allow the entire system and hot water cylinder
to be drained.
Draining taps shall be to the current issue of BS2879.
2.2 Safety Valve
A safety valve need not be fitted to an open vented system.
2.3 Pump
The pump should be fitted in the flow pipe from the boiler and
have isolating valves each side, integral if possible.
A variable duty pump should be set to give a temperature
difference of 11
o
C (20
o
F) between the flow and return, with the
thermostat set at “MAX”, which is about 82
o
C (180
o
F), to give
a design flow rate as shown in Table 3.
See chart for pressure drop of the boiler, diagram 2.2.
High resistance microbore systems may require a higher duty
pump.
2.4 Bypass
A BYPASS MUST BE FITTED, see diagram 2.3 for a suitable
position.
The flow rate through the boiler must not be allowed to fall below
that given in Table 3.
Where the water system can allow the boiler and pump to
operate on bypass only, the bypass
must be placed at least
1.5m away from the boiler.
2.5 Inhibitor
Attention is drawn to the current issue of BS5449 and BS7593
on the use of inhibitors in central heating systems.
If an inhibitor is to be used, contact an inhibitor manufacturer for
their recommendations as to the best product to use.
Note: This boiler has a totally copper water system and does
not require a special inhibitor normally associated with other
types of high efficiency (“condensing”) boilers.
If an existing system is to be reused take special care to drain
the entire system, including the radiators, then thoroughly
cleaning out before fitting the boiler whether or not adding an
inhibitor.
2.6 Open (Vented) Water System
The boiler must be supplied from an unrestricted water supply
taken from a feed and expansion cistern situated at a maximum
height of 27metres (90ft) above the boiler.
The cold feed must be 15mm minimum size.
The vent must rise continuously and be unrestricted.
It is important that the relative positions of the pump, cold feed
and open vent are as shown in diagram 2.3.
2.7 Domestic Hot Water Cylinder
The domestic hot water cylinder must be of the double feed fully
indirect type. Not the single feed self priming type.
2.8 Domestic Hot Water System - Unvented
Where a storage system will not have a vent to atmosphere the
installation must comply with the Building Regulations and local
Water Company bylaws, see also the current issue of BS5546
and BS6700.
If fitting to an existing system the local authority should be
informed.
2.9 Sealed Water Systems
The installation must comply with the appropriate requirements
of the current issue of BS4814, BS5449, BS6759, BS6798 and
BS7074 Part 1 and 2.
See diagram 2.4 for a suggested layout.