4.14 Heat Exchanger
NOTE:
Replacing the heat exchanger
involves disconnecting the appliance from
the flue and air pipes. It is essential that the
flue system is fully reinstated and tested so
we recommend that the appropriate
replacement flue pipe and fittings be
obtained before starting this wor
k
.
Re-assemble all parts in reverse order.
1
.
P
erform 4.
1
General Access.
2.
C
hec
k
that the boiler primary system is
isolated from the mains water supply.
Release pressure from the primary
system and drain down.
3. Remove expansion vessel, pump, gas
valve, fan/venturi, diverter valve and heat
exchanger door (complete with burner) all
as detailed in previous sections. Remove
flow and return pipewor
k
from the push-fit
connections on the manifold underneath
the heat exchanger. Retain securing clips
for re-use.
4. Disengage the flue/air inlet duct/elbow on
top of the boiler. Unscrew the 4 c/sun
k
screws and remove the flue connector
fitting.
5
. Disconnect wiring from temperature
sensors and overheat thermostat.
Remove the spar
k
generator and leads.
Remove the ionisation probe.
6. Disconnect the flexible condensate pipe
at the union just inside the airbox.
7
. Remove two flanged set screws securing
the heat exchanger. Support weight of
heat exchanger before removing the clips
entirely.
8
. Manoeuvre the heat exchanger away
from the support brac
k
ets, then tilt
forward from the bottom to remove.
9. Transfer the extension for the manual
vent to the new heat exchanger.
Fig. 24
42
© Baxi Heating UK Ltd 2015