Instructions on commissioning, maintenance, and troubleshooting for auroSTOR 0020111119_02
33
Metal discharge pipe (D1)
from temperature and pressure
relief valve to tundish
Metal discharge pipe (D2)
from tundish with constant
incline
Thundish
Discharge point
beneath grille
Fixed grille
Gully with
siphon
Safety valve
(e.g. Temperature
and pressure
relief valve)
At least
300 mm
Max.
600 mm
Fig. 6.9 Typical drainage installation
The discharge connections of the temperature and pres-
sure relief valve and the expansion relief valve must be
connected to the supplied tundish via 15 mm copper pip-
ing. The tundish should be mounted vertically, as close
to the cylinder as possible and not more than 600 mm
from the connection of the temperature and pressure
relief valve. It must be mounted in the same room as the
cylinder at a sufficient distance from the electrical com-
ponents. The discharge pipes from the temperature and
pressure relief valve and from the expansion relief valve
can be joined above the tundish using a T-piece
(¬
fig. 4.1
).
The discharge pipe from the 22 mm connection of the
tundish must be laid using copper piping with a diameter
of at least 22 mm to a safe and visible discharge point.
There must be a vertical section of pipe at least 300 mm
long beneath the tundish before any bends or elbows in
the pipework. If the total resistance of the discharge
pipe exceeds the values specified in Tab. 6.4 below, you
must increase the diameter of the piping. When install-
ing the discharge piping, you must observe Directive G3
(
¬
section 2.2
).
Minimum diameter
of discharge pipe
(D2) from tundish
Maximum permis-
sible total resist-
ance, expressed as
straight pipe
length (without
elbows or bends)
Resistance due to
each elbow or bend
22 mm
up to 9 m
0.8 m
28 mm
up to 18 m
1.0 m
35 mm
up to 27 m
1.4 m
Tab. 6.4 Sizing of copper discharge pipe "D2" for G1/2
temperature and pressure relief valve outlet size
Worked example
The example below is for a G1/2 temperature relief valve
with a discharge pipe (D2) having 4 No. 22 mm elbows
and length of 7 m from the tundish to the point of dis-
charge.
From Table 6.4:
Maximum resistance allowed for a straight length of
22 mm copper discharge pipe (D2) from a G1/2 tempera-
ture relief valve is: 9.0 m.
Subtract the resistance for 4 No. 22 mm elbows at 0.8 m
each = 3.2 m
Therefore the maximum permitted length equates to:
5.8 m, which is less than the actual length of 7 m there-
fore calcu late the next largest size.
Maximum resistance allowed for a straight length of
28 mm pipe (D2) from a G1/2 temperature relief valve is:
18 m.
Subtract the resistance of 4 No. 28 mm elbows at 1.0 m
each = 4.0 m.
Therefore the maximum permitted length equates to:
14 m.
As the actual length is 7 m, a 28 mm (D2) copper pipe
will be satisfactory.
A suitable place for the end of the discharge pipe is, for
example, beneath a fixed grille above the odour seal in a
gully with a siphon. Low discharge pipes, for example up
to 100 mm above external surfaces such as car and
other parking spaces, grasslands, etc. can be used pro-
vided that they are secured by a wire fence or some-
thing similar to prevent children from coming into con-
tact with the waste water and provided that the system
is not visible. You must not install any valves or stop
cocks in the discharge pipe.
>
Make sure that the discharge pipe from the tundish to
the drain has a constant downward incline of at least
1:200.
The discharge pipe from the pressure relief valve of the
Vaillant gas-fired wall-hung boiler can be connected to
the horizontal discharge pipe of the cylinder behind the
tundish using a T-piece.
Installation 6