Vaillant ecoTEC plus VU 446/5-5 (H-GB) Installation And Maintenance Instructions Manual page 44

12.7.2 Removing the compact thermal module
Danger!
Risk of death and risk of material damage
caused by hot flue gas.
The seal, heat insulation and self-locking nuts
on the burner flange must not be damaged.
Otherwise, hot flue gases may escape and
cause personal injury and material damage.
▶
Replace the seal each time you open the
burner flange.
▶
Replace the self-locking nuts on the
burner flange each time you open the
burner flange.
▶
If the heat insulation on the burner flange
or on the back panel of the heat ex-
changer shows signs of damage, replace
the heat insulation.
Note
The compact thermal module consists of five main
components:
– Speed-regulated fan,
– Gas valve assembly including support plate,
– Venturi and gas connection pipe,
– Burner flange,
– Premix burner.
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4
1. Disconnect the test system's silicone pipe for checking
the airflow rate (1).
2. Undo the fixing screw (2) and remove the air intake
pipe (3) from the intake stub.
3. Unscrew the union nut (4) from the gas valve
assembly.
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Installation and maintenance instructions ecoTEC plus 0020261389_03
5
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4. Remove the plug for the earth cable (5) from the igni-
tion electrode.
5. Remove the plug (4) from the ignition device.
6. Remove the plugs (1) and (2) from the fan motor by
pushing in the latching lug.
7. Remove the plug from the gas valve assembly (3).
8. Unscrew the four nuts (6).
9. Remove the fixing tab (7) for the air intake pipe.
10. Pull the assembly group for the compact thermal
module (8) out of the heat exchanger.
11. Check the burner and the heat exchanger for damage
and dirt.
12. If necessary, clean or replace the components accord-
ing to the following sections.
13. Fit a new burner flange seal.
14. Check the insulating mat on the back panel of the heat
exchanger.
–
If you notice any signs of damage, replace the insu-
lating mat.
15. Check the insulating material on the burner flange.
–
If you notice any signs of damage, replace the insu-
lating mat.
12.7.3 Cleaning the heat exchanger
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1. Never undo the four nuts on the threaded pin (1) or
tighten them.
2. Clean the spiral immersion heater (2) of the heat ex-
changer using water or, if required, vinegar (up to a
maximum acid content of 5%). Allow the vinegar to act
on the heat exchanger for 20 minutes.
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