Melitta Caffeo Solo outlet valve maintenance

Introduction

The gaskets in the outlet valve are heavily used. If the valve leaks or doesn't let water through anymore you can replace it.

Unscrew and remove six Torx T10 on the rear.
Lever the rear cover off. It will most likely be quite stuck and you will need to apply some force. You must use plastic lever tools to prevent damaging the cover.

Press carefully into the slits on the sides using a minus screwdriver or a flat metal spatula, to release the clasps on the upper surface. These may be well tight and you have to use some force.
You should have created a separation between the upper surface and side panels. Now lever the upper covering away using a plastic tool. This may be quite stuck and you may apply some force.

Place a plastic tool in the crack between front panel and left side panel and widen it. Then push the side panel to the back. The side panel will be quite stuck and you may apply some force to do this.
Remove the hose from the water tank to the pump.
Remove the side panel.

Place a plastic tool into the crack between the front panel and the right side panel and widen it. Then push the side panel to the back. This may be quite stuck and you may need to apply some force.
Remove the side panel.

There are three latches securing the valve lid. Carefully lift the lid up using a metal spudger.
Lifting the lid exposes a spring, a plunger and its holder, an O-ring and the seal of the plunger. The photo shows clearly the imprint of the valve seat, so the valve doesn't close properly. The plunger tends to break but the spare plunger in the repair kit is made of metal.
Note the order and orientation of the parts (photo).
Alternatively you can replace the complete valve, it's not too expensive.