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1.15 SYSTEM REQUIREMENTS - CENTRAL HEATING
a. The method of filling, refilling, topping up or flushing sealed
primary hot water circuits from the mains via a temporary
hose connection is only allowed if acceptable to the local
water authority.
b. Antifreeze fluid, corrosion and scale inhibitor fluids suitable
for use with boilers having aluminium heat exchangers may
be used in the central heating system.
General
1. The installation must comply with all relevant national and
local regulations.
2. Design the system for flow temperatures up to 80
3. The system components must be suitable for an operating
pressure of 3 bar and a maximum temperature of 110°C.
The following components are incorporated within the
appliance:
a.
Circulating pump.
b.
PRV, with a non-adjustable preset lift pressure of
3 bar.
c.
Pressure gauge, covering a range of 0 to 4 bar.
d.
An 8 litre expansion vessel, with an initial charge
pressure of 0.75 bar.
4. Makeup Water. One of the following provisions must be
made for replacing system water loss:
a.
Manually filled vessel
The vessel must:
Have a visible water level
Be mounted at least 150 mm above the system's
highest point
Connect through a non-return valve to the system
Be at least 150 mm below the makeup vessel on the
return side of the radiators
b.
System prepressurisation.
The efficiency of the expansion vessel will be
reduced in a pressurised system; a larger vessel or
smaller system volume may be necessary.
If the vessel's capacity is not sufficient, an additional
vessel must be installed on the return to the boiler.
If the system is not pressurised, the cold water
capacity must not exceed 143 litres.
Guidance on vessel sizing is given in table above.
CH Return
Temporary hose
(disconnect after filling)
Ecl 6053
12
Section 1 - General
Mains
water supply
Hose unions
Additional
stop valve
Double check valve
assembly
note direction of flow
(
Table 3 Vessel Sizing
PRV setting
Vessel charge pressure
System pre-charge pressure bar
System volume
(litres)
25
50
75
o
C.
100
125
150
175
190
200
250
300
For other system volumes
multiply by the factor across
Model
Max CH uutput
Water flow rate
Temp differential
Head available
for system
5. Filling
The system may be filled by the following method:
Where the mains pressure is excessive a pressure
reducing valve must be used to facilitate filling.
a.
Thoroughly flush out the whole system with cold
water.
b.
Fill and vent the system until the pressure gauge
registers 1 bar and examine for leaks
Refer to Section
2.18
c.
Check the operation of the PRV by raising the water
pressure until the valve lifts. This should occur within
0.3 bar of the preset lift pressure.
d. Check no escape of water occurs except at the
discharge point
e.
Release water from the system until the
minimum system design pressure is reached;
1.0 bar if the system is to be pre-pressurised.
)
bar
bar
None
Expansion vessel
volume (litres)
1.6
3.1
4.7
6.3
7.8
9.4
10.9
11.9
12.5
15.6
18.8
0.063
15
18
kW
15
18
l/min
10.7
13
(gal/min)
(2.4)
(2.8)
C
20
20
o
m.w.g.
5
4.5
(ft.w.g.) (16.2)
(14.7)
Installation and Servicing
3.0
0.5 to 0.75
1.0
1.8
3.7
5.5
7.4
9.2
11.0
12.9
14.0
14.7
18.4
22.1
0.074
24
30
24.2
30.3
17.2
21.5
(3.8)
(4.7)
20
20
3.3
1.9
(10.8)
(6.2)
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