MAINTENANCE INSTRUCTIONS
50
Electric fan
(see fig. 1)
•
Remove and dismantle the entire burner unit (see
6.6.1 “Cleaning the burner unit”).
•
Use an 8 mm spanner to unscrew the four nuts
securing the electric fan to the gas manifold and
then remove the electric fan, noting the positions of
the washer and diaphragm.
•
Remove the air intake duct, unscrew the two fixing
screws from the venturi and remove the electric fan,
paying particular attention not to damage the cork
gasket.
•
Replace the electric fan and re-assemble the
components following the above procedure in
reverse order.
•
Switch on the electricity, water and gas supplies and
check the soundness of the joint by measuring the
CO
2
levels;
Expansion vessel
(see fig. 2)
•
Close the shut-off valves and drain the central
heating circuit of the boiler.
•
Use a 19 mm spanner to unscrew the pipe coupling
to the vessel.
•
Unscrew the fixing screws and remove the upper
mounting bracket. Remove the expansion vessel
from the front of the boiler.
•
Replace the expansion vessel and re-assemble the
components following the above procedure in
reverse order.
•
Switch on the electricity, water and gas supplies
and fill the system with water. Check for any leaks
from the joints and bleed off any air from the circuit;
D.H.W heat exchanger
(see fig. 3)
•
Close the shut-off valve and drain the domestic hot
water circuit and central heating circuit of the boiler.
•
Use a 4 mm Allen key to unscrew the two screws
securing the heat exchanger to the multiplex unit.
•
Remove the heat exchanger from the left side of the
boiler, note its orientation.
•
Fit new rubber washer, inserting them in their
housings on the multiplex unit.
•
Replace the heat exchanger and re-assemble the
components following the above procedure in
reverse order.
•
Switch on the electricity, water and gas supplies, fill
the system with water and check for any leaks from
the joints.
fixing bracket
expansion vessel
Fig. 2
venturi
electric fan
Fig. 1
d.h.w heat
exchanger
fixing
screws
Fig. 3