Heating engineer
22
3
Figure 3.7
Horizontal pipe counter-slope
2-3%
For proper installation of the wall external terminals for
the flue gas exhaust and combustion air intake, follow the
details given in Figure 3.8
Figure 3.8
Wall terminal position
IN
combustion air intake
OUT flue gas exhaust
A
recommended posi-
tion (OK)
B
allowed position (OK)
C
position NOT allowed
(NO)
IN
OUT
A
IN
OUT
B
IN
OUT
C
NO
OK
3.3.5
Example of calculation
Let's assume to install a G100 in C13 type installation
(Figure 3.3
p. 19). The air/fumes system will be realized
with Ø 80 separate pipes in the following way:
▶
7 m of Ø 80 flue gas exhaust pipe
▶
1 90° Ø 80 elbow on the flue gas exhaust pipe
▶
6 m of Ø 80 air pipe
It is therefore possible to proceed with the verification, re-
membering that the maximum allowed pressure drop is
200 Pa (Table 3.11
▶
Ø 80 flue gas exhaust pipe
7 m x 22,4 Pa/m =
156,8 Pa
▶
90° elbow
1 x 31,6 Pa = 31,6 Pa
▶
Ø 80 air pipe
6 m x 7,5 Pa/m =
45,0 Pa
Total pressure drop =
233,4 Pa
Total pressure drop of the piping system is greater than
the maximum allowed pressure drop (200 Pa), therefore
the installation is not allowed.
The installation can be done if one of the following steps
is taken:
▶
Reduce the length of the air/fumes pipes.
▶
Increase pipe diameter, e.g. by using Ø 110. In this case
the total pressure drop would be:
7 m x 4,6 Pa/m =
32,2 Pa
1 x 8,6 Pa = 8,6 Pa
6 m x 1,6 Pa/m =
9,6 Pa
Total pressure drop =
50,4 Pa
which is therefore compatible with the maximum allowed
pressure drop.
3.4
FLUE GAS CONDENSATE DISCHARGE
The G unit is a condensing appliance and therefore pro-
duces condensation water from combustion flue gases.
Condensate acidity and exhaust regulations
The flue gas condensate contains aggressive acid
substances. Refer to applicable regulations in force
for condensate exhaust and disposal.
If required, install an acidity neutraliser of ade-
quate capacity.
Do not use gutters to discharge the condensate.
Do not discharge the fume condensate in gut-
ters, due to the risk of materials corrosion and ice
formation.
3.4.1
Flue gas condensate connection
The fitting for the flue gas condensate discharge is locat-
ed in the lower part of the appliance.
▶
The condensate discharge pipe must be connected to
a suitable discharge manifold.
▶
The junction between the pipe and the manifold must
remain visible.
3.4.2
Condensate discharge installation
A condensate drain kit is supplied as standard and must
be connected (by the installer) to the appropriate outlet
in the lower part of the gas unit heater.
How to install the condensate drain kit
1.
Unscrew the upper seal of the condensate drain
siphon.
2.
Insert the condensate discharge connection neck ring
into the upper seal with the connection towards the
outside.
3.
Screw the seal back onto the siphon.
4.
Screw the siphon onto the condensate drain at the
bottom of the gas unit heater.
5.
Adjust the siphon so that the outlet port of the siphon
is facing the intended path of the drain pipe (Figure
p. 23).
The output in the lower part of the appliance has
been designed so that it remains usable even in
case of mounting of the revolving wall support
bracket (optional, Paragraph 2.5
The connection of the discharge to the sewerage
