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1.17 SYSTEM REQUIREMENTS
Central Heating
Notes
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. The installation should be designed to work with flow temperatures
of up to 86
C.
o
3. All components of the system must be suitable for a working pressure
of 3 bar and a maximum design temperature of 110
should be taken in making all connections so that the risk of leakage
is minimised.
The following components are incorporated within the appliance:
a.
Circulating pump.
b.
Safety valve, 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. 'Make-up' Water. Provision must be made for replacing water
loss from the system, either :
a.
From a manually filled 'make-up' vessel with a readily visible
water level. The vessel should be mounted at least 150mm
above the highest point of the system and be connected
through a non-return valve to the system, fitted at least 150mm
below the 'make-up' vessel on the return side of the radiators.
or
b.
Where access to a 'make-up' vessel would be difficult, by
pre-pressurisation of the system.
The maximum cold water capacity of the system should
not exceed 143 litres, if not pressurized. However, if the
system is to be pressurized, the efficiency of the expansion
vessel will be reduced and a larger vessel (or smaller
system volume) may be necessary. If the capacity of the
vessel is not considered sufficient for this, or for any other
reason, an additional vessel MUST be installed on the
return to the boiler.
Guidance on vessel sizing is given in the table above.
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
1bar and examine for leaks.
c.
Check the operation of the safety valve by raising the water
pressure until the valve lifts. This should occur within
0.3bar of the preset lift pressure.
d.
Release water from the system until the
minimum system design pressure is reached;
1.0 bar if the system is to be pre-pressurised.
CH Return
Temporary hose
(disconnect after filling)
Installation and Servicing
SECTION 1 - GENERAL
C. Extra care
o
Mains
water supply
Hose unions
Additional
stop valve
Double check valve
assembly
(
note direction of flow
Safety valve setting
Vessel charge pressure
System pre-charge pressure
System volume
100
125
150
175
190
200
250
300
For other system volumes
multiply by the factor across
Water Flow Rate and Pressure Loss
Max CH Output
Water flow rate
Temperature Differential
Head available for
system
Domestic Hot Water
1. The domestic hot water service must be in accordance with BS
5546 and BS 6700.
2. Refer to Table 1 for minimum and maximum working pressures. In
areas of low mains water pressures the domestic hot water regulator
may be removed from the DHW flow turbine cartridge. Refer to
Section 3.30. The boiler will require the flow rate to be set to obtain a
temperature rise of 35
3. The boilers are suitable for connection to most types of washing
machine and dishwasher appliances.
4. If the shower/mixer valve does not incorporate non-return
valves the following must be followed:
a.
The cold inlet to the boiler is fitted with an approved anti-
vacuum or syphon non-return valve.
b.
Hot and cold water supplies to the shower are of equal
pressure.
5. Hard Water Areas
Where the water hardness exceeds 200mg/litre (200ppm), it is
recommended that a proprietary scale reducing device is fitted into
the boiler cold supply within the requirements of the local water
company.
IMPORTANT. Provision MUST be made to accomodate the expansion
of DHW contained within the appliance. If the DHW inlet contains a
back flow prevention device or non-return valve, e.g. a water meter,
then a mini expansion vessel should be fitted between the device and
the boiler in the cold inlet pipe.
Cold water, rising main & pipework in exposed areas need to be
suitably lagged to prevent freezing.
DHW Expansion Vessel Kit available from Ideal.
)
bar
bar
bar
(litres)
25
50
75
kW
l/min
(gal/min)
C
o
m.w.g.
(ft.w.g.)
C at the tap furthest from the boiler.
o
3.0
0.5 to 0.75
None
1.0
Expansion vessel
volume (litres)
1.6
1.8
3.1
3.7
4.7
5.5
6.3
7.4
7.8
9.2
9.4
11.0
10.9
12.9
11.9
14.0
12.5
14.7
15.6
18.4
18.8
22.1
0.063
0.074
24.2
17.3
(3.8)
20
3.4
(11.1)
15
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