Domestic Hot Water Circuit - Baxi COMBI 224 Installation And Service Manual

5 Before installation
Fig.31 Filling loop
B
A
Fig.32 Circuit plan
G
B
C
D
E
38
A
B
A filling loop is supplied with the 424 and 428 models.
The filling method adopted must be in accordance with all relevant water
supply regulations and use approved equipment.
Your attention is drawn to:
for GB: Guidance G24.2 and recommendation R24.2 of the Water Regu­
lations Guide.
for IE: the current edition of I.S. 813 Domestic Gas Installations.
The sealed primary circuits may be filled or replenished by means of a
temporary connection between the circuit and a supply pipe, provided a
"Listed" double check valve or some other no less effective backflow pre­
vention device is permanently connected at the inlet to the circuit and the
temporary connection is removed after use.
PN-0000231

5.6.2 Domestic hot water circuit

A
B
C
D
A
E
F
G
All DHW circuits, connections, fittings, etc. should be fully in accordance
with relevant standards and water supply regulations.
F
Your attention is drawn to:
for GB: Guidance G17 to G24 and recommendation R17 to R24 of the
PN-0000215
Water Regulations Guide.
for IE: the current edition of IS 813 Domestic Gas Installations.
The Water Regulations recommendations for England and Wales prohibits
backflow from appliances into the wholesome water supply due to thermal
expansion. However this type of instantaneous combination boiler, with
less than 15 litres of stored capacity, does not require any backflow pre­
vention device as any thermal expansion is accommodated within the ap­
pliance. It is possible in certain circumstances that other cold water de­
mands (e.g. washing machines, flushing of WCs) may affect the DHW
function of the boiler. In these instances the fitting of a backflow prevention
device and expansion vessel is recommended.
Filling loop
Flow and return taps
Boiler
Expansion vessel
Check valve
Pressure reducer
Stop tap
To hot tap
Other tap outlets
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