Connection On The Water Side; Dhw Expansion Vessel; Electrical Connection; Connection Diagram - Bosch Stora WP 400 PK Installation And Service Instructions Manual

Mounting method
5.2.3

Connection on the water side

NOTICE
Damage to cylinder connections due to contact corrosion.
▶ If copper is used for the connection on the domestic water side: use
a connection fitting made of brass or gunmetal.
▶ Make the cold water connection in accordance with DIN 1988-100
using suitable individual fittings or a complete safety assembly.
▶ The type-tested pressure-relief valve must be able to blow off at least
the volumetric flow rate that is limited by the volumetric flow rate set
at the cold water inlet (Chapter 6.2, page 35).
▶ Set the type-tested pressure-relief valve so that the permissible
cylinder operating pressure cannot be exceeded.
▶ Terminate the discharge pipe where it will be easily visible in the
frost-proof area via a dewatering point. The discharge pipe must be at
least equal to the outlet cross-section of the pressure relief valve.
NOTICE
Damage due to positive pressure!
▶ If using a non-return valve: install a pressure-relief valve between the
non-return valve and the cylinder connection (cold water).
▶ Never close the blow-off opening of the pressure-relief valve.
▶ Fit a sign near the discharge pipe of the pressure-relief valve with the
following warning: "For safety reasons, water may be expelled from
the discharge pipe during heating! Do not close!"
If the static system pressure exceeds 80 % of the pressure relief valve
excess pressure:
▶ Install a pressure reducer upstream.
5.2.4

DHW expansion vessel

To avoid water loss via the pressure-relief valve, a suitable expansion
vessel can be installed for potable water.
▶ Install the expansion vessel in the cold water line between the
cylinder and the safety assembly. Potable water must flow through
the expansion vessel each time DHW is drawn off.
The following table serves as a guide for sizing an expansion vessel. Sizes
may deviate for other makes of expansion vessel with different useful
capacities. Details refer to a cylinder temperature of 60 °C.
Cylinder type Vessel
pre-charge
pressure =
cold water
pressure
WP 400 PK 4 bar
WP 500 P 4 bar
WP 700 P 4 bar
Table 18 Guide, expansion vessel
34
Vessel size in litres
according to the excess
pressure of the pressure-
relief valve
6 bar 8 bar 10 bar
33 18 18
60 25 18
60 33 25
5.3

Electrical connection

DANGER
Risk to life due to electric shock!
▶ Prior to establishing the electrical connection, isolate the heating
system from the power supply (230 V AC).
For a detailed description of the electrical connection, see the relevant
installation instructions.
Connection to a wall mounted boiler
▶ Connect the plug of the cylinder temperature sensor to the wall
mounted boiler ( Figure 7, page 60).
5.4

Connection diagram

Fig. 2 Connection diagram on the domestic water side
BWAG DHW expansion vessel (recommendation)
E Drain work
KW Cold water connection
R Cylinder return
SP
V Cylinder flow
SP
SG Safety assembly to DIN 1988-100
WW DHW outlet
ZL DHW circulation connection
10 Water pressure relief valve
14 Discharge pipe
15.1 Test valve
15.2 Non-return component
15.3 Pressure gauge connector
20 On-site DHW circulation pump
21 Shut-off valve (on-site)
22 Pressure reducer (if required, accessory)
Stora – 6721835341 (2021/04)