Glow-worm EnergySaver 80 - Manual (Page 8)

8
221837B
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
0 1 2 3 4 5 6
Flow rate (gallons/minute)
35 40
70
7 8
2.0
0164M
Diagram 2.1
Diagram 2.2
TABLE 3
2 Water System
4364 S
BOILER
DRAIN
POINT
Design Minimum
Flow Rate Flow Rate
Energysaver 70 26.8L/min 19.6L/m
Energysaver 80 30.5L/min 22.5L/m
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.
The use of microbore systems is not recommended.
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.
Maximum water pressure 3 Bar.
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.