Nibe VPB series User's And Installer's Manual page 12

Pipe installation
General
NOTE
Pipe installation must be carried out in accord-
ance with current norms and directives
NOTE
This installation is subject to building regulation
approval, notify the local Authority of intention
to install.
NOTE
Use only manufacturer's recommended replace-
ment parts.
Overflow water from the safety valves goes via non-
pressurised collecting pipes to a drain so that hot water
splashes cannot cause injury. These non-pressurised
collecting pipes shall not be used for anything else. A
discharge pipe from the tundish connected to the expan-
sion relief valve (safety valve) shall also be connected to
a drain in the same way.
Please note that the connection of the T&P-valve should
not be used for any other purpose.
Valves may not be positioned between the expansion
valve and the vessel.
Overflow pipes from tundish must be routed with a fall
and at least 300 mm long, before bends or angles in the
pipework (see image).
The tundish should be installed away from electrical
components.
Valve outlet size
G1/2
G1/2
G1/2
G3/4
G3/4
G3/4
G1
G1
G1
The tables shows the dimension of the copper overflow pipe for common safety valve connection size.
12 Chapter 3 | For the Installer
Minimum size of dis- Minimum size of dis-
charge pipe charge pipe from
tundish
15 mm 22 mm
15 mm 28 mm
15 mm 35 mm
22 mm 28 mm
22 mm 35 mm
22 mm 42 mm
28 mm 35 mm
28 mm 42 mm
28 mm 54 mm
Metal discharge pipe from
temperature relief valve to tundish.
Safety device
600 mm maximum
(e.g. temperature
relief valve).
300 mm
minimum
Metal discharge pipe from tundish,
with continous fall.
NOTE
The expansion vessel accomodates expansion
that results from heating the water inside the
unit. The expansion vessel must be connected
between the expansion valve and the cylinder.
The location of the expansion vessel should al-
low access to recharge the pressure as and when
necessary.
Maximum resistance
allowed, expressed
as a lenght of
straight pipe (i.e. no
elbows or bends)
up to 9 m
up to 18 m
up to 27 m
up to 9 m
up to 18 m
up to 27 m
up to 9 m
up to 18 m
up to 27 m
Tundish
Discharge below
fixed grating.
Fixed grating
Trapped gulley
Possible wall
Resistance created by
each elbow or bend
0.8 mm
1.0 mm
1.4 mm
1.0 mm
1.4 mm
1.7 mm
1.4 mm
1.7 mm
2.3 mm
VPB/VPBS