Vaillant ecoTEC exclusive 627 Installation And Maintenance Instructions Manual page 39

8. After installing the new gas valve assembly, carry out a
leak-tightness test (→ Page 30).
9. Close the front casing.
10. Switch on the product.
11. Navigate to Menu → Installer level → Diagnostics
menu → D.052 Min. gas valve steps offset and con-
firm by pressing .
12. Enter the offset value that you read off and confirm by
pressing .
13. Start up the heat generator.
13.7.3 Replacing the fan
1. Remove the air intake pipe.
2. Remove the gas valve (→ Page 38).
A
4 2 3
B
1
3. Remove the plug (1) from the fan.
4. Unscrew the three screws between the mixture pipe
and the fan flange.
5. Replace the defective fan.
6. Reinstall the new fan in the reverse order. You must
use new seals for this. Ensure that the order in which
the three screws are screwed in between the fan and
the mixture pipe corresponds to the numbering (2), (3)
and (4).
13.7.4 Replacing the heat exchanger
1. Drain the product. (→ Page 36)
2. Remove the compact thermal module. (→ Page 34)
3. Remove the left side section.
4. Detach the condensate discharge hose from the heat
exchanger.
0020193966_04 ecoTEC exclusive Installation and maintenance instructions
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2 3
5. Remove the clamps (2) and (3) from the flow connec-
tion and the return connection.
6. Undo the union nut (4) on the pump's return connection
and remove the pipe from the return connection on the
heat exchanger.
7. Remove the pipe from the flow connection on the heat
exchanger.
8. Remove two screws (1) on each of the two retainers.
9. Remove the all-gas sensor. (→ Page 41)
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3
2
10. Remove the lower three screws (2) on the rear section
of the retainer.
11. Support the heat exchanger and swing the retainer (3)
to the side around the top screw (1).
12. Pull the heat exchanger downwards and to the left, and
remove it from the product.
13. Push the new heat exchanger into the air/flue connec-
tion from above.
14. Push the heat exchanger into the groove in the retainer
on the right and swing the retainer on the left back into
its original position.
◁
The heat exchanger is now held in place by the
guides in the two retainers.
15. Install the two front clamps on the retainers and then
fit the screws you removed in the retainer on the left
(always work in this order).
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