Condensing Heat Exchanger; Function; Removal - Biasi Advance Plus 25C ERP Service Manual

5

CONDENSING HEAT EXCHANGER

5 .1 Function

The Condensing heat exchanger "A" in Figure 5.1 has the func-
tion of transferring heat produced from combustion of the gas
and from the flue exhausted gas to the water circulating in it.
B
C
Figure 5 .1
By reducing the combustion products temperature, the latent
heat of the vapour is transferred to the water circuit, allowing an
extra gain of useful heat.
The condensed vapour is then drained through the condensate
trap "C" and the draining pipe "B".

5 .2 Removal

Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
1 Disconnect the flue system from the boiler.
2 Remove the fan group (rubber pipe, gas pipe) following the
instructions from 1 to 6 in section "17.2 Removal of the Air
box and the Fan" on page 41.
3 Disconnect the detection electrode connector "D", the ignition
electrodes connector "E" and the earth wire "F".
4 Disconnect the fan connector "G" by pressing the plastic
hook placed on the side of the connector (Figure 5.2).
5 Unscrew the connector "M" and remove the pipe "L" (Figure
5.2).
6 Unscrew the nuts "H" (Figure 5.2).
7 Remove the fan-burner group "I".
8 Empty the primary circuit of the boiler.
9 Remove the clips "J" (Figure 5.2).
10 Loosen the connection "L" and slightly move the pipe "K" up-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
11 Loosen the connection "O" and slightly move the pipe "P" up-
wards, turn it towards left (Figure 5.2) and then move the pipe
downwards freeing it from the Condensing heat exchanger.
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CONDENSING HEAT EXCHANGER
A
H
J
E
G
P
O
Figure 5 .2
Figure 5 .3
12 Unscrew the screws "Q" and remove the clamps (Figure 5.3).
13 Disconnect the two connectors "R" by pressing the plastic
hook placed on the side of the connector (Figure 5.3).
14 Remove the Condensing heat exchanger by levering it and
sliding it forwards.
F
D
I
K
L
N
M
R
Q