Note To Installers; Secondary System; Secondary Return - Vaillant uniSTOR VIH GB 125 S Instructions For Installation And Use Manual

4 Note To Installers

4 Note To Installers
This product has been assessed and found to comply
with the requirements of the Building Regulations for
unvented hot water storage systems and must not be
altered or modified in any way.
The installation must be carried out by a competent
person and be in accordance with the relevant
requirements of the Local Authority, Building
Regulations, Building Regulations (Scotland), Building
Regulations (Northern Ireland), and the bye-laws of the
local Water Undertaking. The installation is subject to
Building Regulation approval, notify the Local Authority
of intention to install. In the event of parts replacement,
use only genuine spare parts supplied by Vaillant Ltd.

4.1 Secondary System

The uniSTOR is provided with all necessary safety and
control devices for unvented DHW operation.
These are as follows:
A A prefitted temperature and pressure relief valve
(95 °C, 7 bar).
B A Thermal cut set at 90 °C which when wired to the
2 port valve will isolate the heat source in the event
of failure of the cylinder thermostat.
C A cylinder thermostat (20 °C - 60 °C)
D Expansion relief valve (6.0 bar) incorporating a non
return valve.
E Pressure limiting valve (3.5 bar) incorporating a line
strainer.
Check that the cylinder has been supplied with the
following:
– Packed inside cylinder carton
- Water control pack (pressure reducing valve,
expansion relief valve; connections for: balanced cold
water, secondary return, expansion vessel)
- Motorised 2 port valve
- Tundish
- Cylinder drain valve,
- Installation and user instructions,
- Mounting kit for expansion vessel.
Expansion vessel:
- 12 litre for VIH GB 125/155
(max. storage volume by 3,5 bar = 155 l)
- 18 litre for VIH GB 180/210
(max. storage volume by 3,5 bar = 255 l)
- 25 litre for VIH GB 260/300
(max. storage volume by 3,5 bar = 315 l)
8
Accessories:
- Additional immersion heater 3 kW
- VR 65 Control Center for new
Vaillant boilers
Prior to installation, ensure that the cylinder is stored
upright in dry conditions. The uniSTOR must be kept
upright during transportation.
Please also refer to "General Requirements" in the
installation instructions supplied with the boiler.

4.2 Secondary Return

A scondary return connection is provided in the water
control pack.
Connect onto the 1/2" pipe on the control group using a
WRAS approved circulation pump which incorporates a
check valve to prevent backflow (see fig. 6).
No. 0020006765
No. 307 215
uniSTOR GB