*****INTERNAL*****30 R_D proof- 26.10.2022 / 09:15:46- VaillantGroup\DOC-agt\Brand\VIH_QW_190_6\ENG\OI-II_GB_0020291525
0020291525_04 Installation and maintenance instructions
29
5.5
Installing potable water pipes
To connect the potable water pipes to the domestic hot water
cylinder, various piping sets are offered as accessories for
surface or concealed installation.
The piping, which is to be set up on-site, requires the follow-
ing components:
–
Domestic hot water thermostatic mixing valve
–
Potable water expansion vessel, if required
–
Pressure reducer in the cold water pipe (if required)
–
Non-return valve in the heating circuit (if required)
–
Service valves
–
Circulation pump for anti-legionella function, if required
The domestic hot water thermostatic mixing valve ensures
that the hot water from the cylinder is mixed with cold water
to produce water with a maximum temperature between 30
and 70 °C as required. When starting up the heating install-
ation, if you set the domestic hot water thermostatic mixing
valve to the required maximum temperature, this maximum
temperature is retained at the domestic hot water draw-off
points.
▶
When installing the supply pipes, observe the set-up in-
structions that are included with the relevant accessories.
▶
To guarantee effective scald protection, set the thermo-
static mixing valve to < 60 °C and check the temperature
at a domestic hot water draw-off point.
5.6
Hydraulic connection
Caution.
Risk of damage caused by heat transfer
when welding.
The heat that is transferred during welding
may damage the cylinder and its components
as well as the connection seals.
▶
Protect the product and its components.
▶
Do not weld the connectors if these have
been screwed into the pipe fittings.
Caution.
Risk of material damage to the cylinder.
If an unvented hot water cylinder is fitted at
a high level (eg, loft space), potential dam-
age to the cylinder may occur if the correct
method of draining is not followed.
▶
In certain circumstances and at the dis-
cretion of the installer, install a WRAS ap-
proved automatic air vent on the hot water
outlet at the highest point.
3
4
5
6
7
8
A
2
1
B
A
Installation alternative
for the potable water
expansion vessel in the
product
B
Installation alternative
for the potable water
expansion vessel on the
safety assembly
1
15 mm diameter con-
nection, e.g. potable
water expansion vessel
2
22 mm diameter con-
nection, e.g. potable
water expansion vessel
3
Cold water supply
4
Safety assembly
5
Expansion relief valve
6
Domestic hot water
cylinder drain valve
7
Tundish
8
Temperature and pres-
sure relief valve
5.6.1
Installing the safety assembly
Caution.
Excessive pressure in the domestic hot
water cylinder
Excessive pressure in the domestic hot water
cylinder may cause the cylinder to burst.
▶
Ensure that the expansion relief valves
are not blocked.
▶
Ensure that there is no isolation valve
between the safety assembly and the
cylinder.
