0020285063_05 Installation and maintenance instructions
15
Size of
the outlet
valve
Minimum
diameter
of the
discharge
pipe D1
Minimum
diameter
of the dis-
charge
pipe from
the tun-
dish D2
Maximum
permiss-
ible res-
istance,
inform-
ation
on the
length of
a straight
pipe
Resist-
ance per
elbow or
bend
1/2"
15 mm
22 mm
28 mm
35 mm
9 mm
≤
18 m
≤
27 m
0.8 m
1.0 m
1.4 m
3/4"
22 mm
28 mm
35 mm
42 mm
≤
9 m
≤
18 m
≤
27 m
1.0 m
1.4 m
1.7 m
1"
28 mm
35 mm
42 mm
54 mm
≤
9 m
≤
18 m
≤
27 m
1.4 m
1.7 m
2.3 m
Sample calculation
The following example corresponds to a temperature and
pressure relief valve G1/2 with a drain pipe
(D2)
with four 22
mm elbows and a length of 7 m from the tundish to the drain-
age point. According to the table, the maximum permiss-
ible resistance for a straight length of a 22-mm-thick cop-
per discharge pipe
(D2)
of a thermal expansion relief valve
G1/2 is 9.0 m. The resistance of the four 22 mm elbows,
which are each 0.8 m in length, must be subtracted from this,
i.e. a total of 3.2 m. The maximum permitted length is ac-
cordingly 5.8 m and is therefore below the current length of
7 m. The calculation must therefore be performed using the
second largest size. The maximum permissible resistance
for a straight length of a 28-mm-thick pipe
(D2)
of a thermal
expansion relief valve G1/2 is 18 m. The resistance of the
four 28 mm elbows, which are each 1.0 m in length, must be
subtracted from this, i.e. a total of 4.0 m. The maximum per-
mitted length is accordingly 14 m. As the current length is
7 m, a 28 mm copper pipe
(D2)
should be selected.
A suitable location for the drain pipe terminal is, for example,
beneath a fixed mesh above the odour trap in a soakaway
with a siphon. Low drain pipework, for example up to
100 mm above external surfaces (car parks, meadows, etc.)
can be used provided that it is protected by a wire fence
or something similar to prevent children from coming into
contact with the waste water and provided that the system
is not visible. Do not install any valves or stopcocks on the
drain pipework.
Make sure that the drain pipe from the tundish to the drain
has a constant downward gradient of at least 1:200. The
drain pipe for the heat generator expansion relief valve can
be connected to the horizontal drain pipe for the cylinder
behind the tundish using a T-piece.
Note
The temperature and pressure relief valve is pre-
installed with a seal. If this seal is displaced, there
is a risk that it will tear. In this case, replace the
defective seal with a suitable seal.
≤ 600 mm
≥ 300 mm
D2
2
1
D1
Drain pipe
1
Temperature and pres-
sure relief valve
2
Tundish
5.2.9
High-level drain
Installing the highest drain is permitted as long as this does
not present a danger to anyone in or outside the building at
the drain point. Examples of points to consider when decid-
ing whether a location is suitable for the highest drain:
–
The possibility (taking the wind into account) that a per-
son might stay in the area where the water is drained
for a prolonged period of time, and, if this is the case,
whether the water is sufficiently cooled by that point to
pose no danger. The thermal conductivity of the material
surfaces, the climatic conditions, the installation location
and the drain pipework direction can, to different extents,
contribute to reducing the temperature of the water that is
being drained.
–
The position of the windows and other openings.
–
The probability of prams being under the drain opening.
–
The resistance of the surface to hot water.
–
The possibility of ice forming if water drains onto access
paths.
5.2.10 thermostatic valve
A thermostatic mixer tap may be required in order to limit the
product's outlet temperature.
▶
Install the thermostatic valve in accordance with the man-
ufacturer's specifications.
▶
Ensure that no part of the safety assembly is insulated
and that the thermostatic mixer tap is therefore connec-
ted in accordance with the cold water inlet's safety as-
sembly.
5.2.11 Insulating lines
We recommend providing the domestic hot water pipe on
the product's outlet with heat insulation in order to reduce
the energy demand for the domestic hot water generation.
Furthermore, all other exposed lines, from the temperature
and pressure relief valve to the tundish, the flow and return
of the cylinder heat exchanger, and the cold water supply
lines, should also be provided with heat insulation.
