Vaillant home combi Installation And Maintenance Instructions Manual page 28

12 Troubleshooting
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12. Lift the heat exchanger up slightly and remove it to-
gether with the condensate tray (1).
13. Undo the four screws (3).
14. Remove the condensate tray.
15. Remove the ignition transformer (2).
16. Use the bolts to secure the condensate tray to the new
heat exchanger.
17. Install the new heat exchanger in reverse order.
12.6.5 Replacing the pump head
1. Disconnect the pump cable from the electronics box.
2. Undo the four bolts (1).
3. Remove the pump head (2).
4. Replace the O-ring.
5. Use four screws to secure the new pump head.
6. Connect the pump cable to the electronics box.
12.6.6 Replacing the expansion vessel
1. Drain the product. (→ Page 26)
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2. Undo the nut (3).
3. Remove both screws on the support plate (1).
4. Remove the support plate.
5. Pull out the expansion vessel (2) towards the front.
6. Insert a new expansion vessel into the product.
7. Screw the new expansion vessel onto the water con-
nection. To do this, use a new seal.
8. Attach the support plate using both screws.
9. Fill and purge the product and, if necessary, the heating
installation.
12.6.7 Replacing the main PCB
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1. Open the electronics box.
2. Pull all of the plugs out from the PCB.
3. Undo the clips on the PCB.
4. Remove the PCB.
5. Install the new PCB in such a way that it clicks into the
groove at the bottom and into the clip at the top.
6. Plug in the PCB plugs.
7. Close the electronics box.
Installation and maintenance instructions HOME 0020224355_00
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