Vaillant ecoMAX 635, Instructions For Installation And Servicing

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9 Parts replacement
Instructions for installation and servicing ecoMAX
9.6 Replacement of main heat exchanger
• Turn off boiler.
• Remove front casing.
• Lower control box.
• Drain boiler as previously described.
• Remove burner, gas valve and fan assembly as pre-
viously detailed.
• Disconnect condensate drain by removing spring clip
(4) and pulling condensate drain (5) downwards.
• Disconnect primary flow connection (7) from main
heat exchanger. (A flexible connection has been provided
in the flow pipe to allow easier access to the return
connection. The flow pipe can be carefully eased out
of the way by bending at the flexible connection).
• Disconnect primary return connection (6) from main
heat exchanger.
• Loosen nylon nut at bottom of heat exchanger.
• Slacken the two top securing bolts (8) and rotate
clamps away from heat exchanger.
• Fully remove bottom screw and securing clamp (8).
• Pull heat exchanger forwards to remove from the boiler.
• Drain any residual water from the heat exchanger.
• Reassemble in reverse order.
• Recommission boiler as previously detailed.
Fig. 9.5 Replacing the main heat exchanger
9.7 Replacement of the electronic control board
Danger!
Ensure you observe the safety precautions
when replacing this component.
• Turn off boiler.
• Remove front casing.
• Lower control box.
• Unclip the back cover from the electronics box and
open the cover.
• Unclip the front cover from the electronics box and
remove the cover.
• Disconnect all wires from the circuit board.
• Unclip the circuit board and remove.
• Remove the display unit and (if fitted) the built–in
timer from the electronics box.
• Clip the new circuit board into position in the electronics
box, reconnect all plug–in wires and refit back cover of
the switch box by clipping the cover back into position.
• Raise the electronics box and reinstall the display unit
and (if fitted) the built–in timer. The display unit and
built–in timer are connected using the contact pins on
the circuit board.
• Recommission boiler as previously detailed.
The new circuit board must be adapted to the heating unit
and its system. To do so, carry out the adjustments to the
display system of the heating unit as shown in Tab. 9.1.
Note!
The values in Tab. 9.1 that appear in bold script
must be adjusted. All other values can be
adjusted as required, or the circuit board default
values can be retained
9.8 Check CO2 content and adjust if necessary
(air–ratio adjustment)
Note!
Checking/adjustment of this value is required in
the following instances: replacement of gas
valve, conversion to or from Natural Gas/ LPG
or if incorrect combustion is suspected!
• Remove the case from the unit.
• Activate full gas rate mode by simultaneously pressing
the ”+” and ”–” buttons on the display system
• Wait at least five minutes, or until the unit has reached
its operating temperature.
• Measure the level of CO
2
content at the exhaust–fume
test outlet (3) (Fig. 9.6). Check the reading against
the corresponding value in tab. 9.2.
• If the exhaust–fume setting requires adjustment,
remove the screw (4) and swivel the air suction pipe
(5) forwards through 90° (Fig. 9.6). DO NOT remove
the air suction pipe.
• Adjust the corresponding setting as required (see
tab. 5.2, p. 26) by turning the screw (6) (fig. 9.7).
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80020014605_00GB_032006 22.02.2006 21:36 Uhr Seite 38