Glow-worm Hideaway 40CF - Manual (Page 7)

7 221807B
PRESSURE LOSS OF BOILER Diagram 2.3
Diagram 2.2
Diagram 2.1
FULLY PUMPED SYSTEM
(DIAGRAMMATIC)
0869
0870
0872
27metres
Max.
PUMP
To Heating
Circuit
INDIRECT
CYLINDER
(Shown with
recommended
thermostat and valve).
22mm VENT
15mm COLD FEED
REFER TO BS 5546
28mm
Distributor tube in
pumped return
connection
BOILER
CL
DRAIN OFF
COCK
PUMPED HEATING AND GRAVITY
DOMESTIC (DIAGRAMMATIC)
1 metre
MIN.
27metres
MAX.
PUMP
To Heating
Circuit
TO INDIRECT
CYLINDER
22mm VENT
15mm
COLD FEED
Distributor tube in
pumped return
connection
BOILER
CL
DRAIN OFF
COCK
600
500
400
300
200
100
0
12
8
4
0
0 4 8 12 16 20 24 28
FLOW RATE (LITRES/MINUTE)
WATER PRESSURE LOSS (mm HEAD OF WATER) WATER PRESSURE LOSS (INCHES HEAD OF WATER)
24
16
800 32
28
20
700
0 1 2 3 4 5 6
FLOW RATE (GALLON/MINUTE)
2.1 Water Pressure Head
This boiler must not be connected to a sealed water system.
This boiler shall only be connected to an open vented cistern
water supply, with a minimum head of 1metre (39in) and a
maximum of 27metre (90ft).
2.2 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 in the system contact should be made
with a manufacturer so that they can recommend their most
suitable product.
If using in an existing system 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.
2.3 Gravity Domestic Hot Water and Pumped
Central Heating
It is recommended that a cylinder thermostat is used to prevent
the stored water temperature becoming too high when the
heating pump is off.
The domestic hot water primary flow and return must be 28mm
od. The installation must comply with the current issue of
BS5546 and BS6700, see diagram 2.1.
If the above conditions cannot be met, it is suggested that a fully
pumped system is used.
2.4 Pumped Central Heating and Domestic Hot
Water
Where a single flow and return is taken from the boiler, a
minimum static head of 1metre (39in) must be provided between
the water level in the cold water cistern and the centre of the
waterway, see diagram 2.2.
2.5 Circulation Pump
Normally the pump should be set to give a temperature difference
of 11
o C (20 o F), across the boiler. At the appropriate flow rate the
resistance through the boiler can be found by reference to the
pressure loss graph, diagram 2.3.
Use a pump with integral valves or fit valves as close to the
pump as possible.
2.6 Domestic Hot Water Cylinder
For all systems supplying domestic hot water the cylinder must
be indirect.
2.7 Safety Valve
A safety valve need not be fitted to an open vented system.
2.8 Draining Tap
A drain tap must be fitted at the lowest points of the system
which will allow the draining of the entire system, including the
boiler and domestic hot water cylinder.
2 Water Systems