Vaillant ecoTEC plus VC 406/5-5 - Checking the gas line for leak-tightness; Hydraulic connection; Connecting the heating flow and heating return

Installation 5
0020261188_00 ecoTEC plus Installation and maintenance instructions 15
product before you carry out the gas leak-
tightness test.
▶ If, during gas leak-tightness tests, you
have closed the gas stopcock that is in-
stalled upstream of the product, relieve
the gas line pressure before you open this
gas stopcock.
▶ Do not reduce the gas pipe dimension downstream of the
gas meter.
▶ Maintain the dimension right up to the product.
▶ Select the correct gas stopcock.
▶ Remove the residues from the gas pipe by blowing
through the gas pipe beforehand.
A
B
1
C
▶ Undo the press connection (A).
▶ Install an approved gas stopcock at the connection (1).
▶ Install the unit on the gas pipe at the product's outlet (B)
by tightening the compression fitting (C).
▶ Install the gas pipe such that it is free from mechanical
stress in accordance with the recognised rules of techno-
logy.
▶ Purge the gas pipe before start-up.
5.5.2 Checking the gas line for leak-tightness
▶ Check the entire gas line properly for leak-tightness.
5.5.3 Hydraulic connection
Caution.
Risk of material damage caused by corro-
sion
Due to non-diffusion-tight plastic pipes in the
heating installation, air gets into the heating
water. Air in the heating water causes corro-
sion in the heat generator circuit and in the
product.
▶ If you use non-diffusion-tight plastic pipes
in the heating installation, ensure that no
air gets into the heat generator circuit.
Note
In order to keep heat losses to a minimum, we
recommend that you provide heat insulation for
the water pipe spigots on the product's outlet and
on the installation.
▶ If you are using plastic pipes in the heating installation,
install a safety cut-out in the heating flow.
– The safety cut-out is required to protect the heating
installation against temperature-related damage if a
fault occurs.
▶ Connect a control or a safety cut-out to the electronics.
(→ Page 18)
5.5.3.1 Connecting the heating flow and heating
return
A
B
C
D
1. Attach the nut to the connection in accordance with
steps (A) to (D).
1
10
11
12
9
7
8
2
3
4 5
6
2. Assemble the heating return connection as shown by
numbers (1) to (6).
3. Assemble the heating flow connection as shown by
numbers (7) to (12).