Heating engineer
34
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 position
(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 G 75 EC in C13 type installation
(Figure 3.3
p. 31). The air/fumes system will be realized
with Ø 80 separate pipes in the following way:
▶
10 m of Ø 80 flue gas exhaust pipe
▶
2 90° Ø 80 elbows on the flue gas exhaust pipe
▶
10 m of Ø 80 air pipe
It is therefore possible to proceed with the verification,
remembering that the residual head is 150 Pa (see Table
p. 32).
▶
Ø 80 flue gas exhaust pipe
10 m x 7,9 Pa/m =
79,0 Pa
▶
90° elbow
2 x 13,1 Pa = 26,2 Pa
▶
Ø 80 air pipe
10 m x 5,8 Pa/m =
58,0 Pa
Total pressure drop =
163,2 Pa
Total pressure drop of the piping system is greater than
the maximum allowed pressure drop (150 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:
10 m x 1,6 Pa/m =
16,0 Pa
2 x 3,5 Pa = 7,0 Pa
10 m x 1,3 Pa/m =
13,0 Pa
Total pressure drop =
36,0 Pa
which is therefore compatible with the maximum allowed
pressure drop.
3.4
FLUE GAS CONDENSATE DRAIN
The Next-G unit is a condensing appliance and there-
fore produces 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 flue condensate in gut-
ters, due to the risk of materials corrosion and ice
formation.
3.4.1
Flue gas condensate connection
The fitting (Ø 18 mm) for the flue gas condensate drain is
located in the lower part of the appliance.
▶
The condensate drain hose must be connected to a
suitable discharge manifold.
▶
The junction between the pipe and the manifold must
remain visible.
3.4.2
Condensate drain kit 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 drain connection neck ring in-
to 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. 35).
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
system must be made at atmospheric pressure, i.e.
by dripping into a siphoned container connected
