How do I replace the cartridges on my Artos F943-VO valve?

Removal

1. Unscrew the handle set screws and remove handles
2. Unscrew the securing nuts that hold the trim plate to the wall (the bottom securing nut may need a set screw to be unscrewed before removal)
3. Remove the trim plate
4. Shut the water off to the valve by closing the service stops
5. Unscrew and remove the outer spindles (a basin wrench may be needed depending on how deep the valve is in the wall)
6. Remove the inner spindles by simply pulling them off the cartridges
7. Remove the securing nuts that hold the cartridges in place (a 32mm socket wrench can be used to remove the securing nut for the bottom (thermostatic) cartridge)
8. The cartridges can now be pulled out as both of them use a friction fit (if they are tight, try fitting the inner spindle back on and using it for leverage)

Assembly

1. Insert new cartridges
2. Screw on the cartridge securing nuts
3. Push the inner spindles on
4. Screw on the outer spindles
5. Open up the service stops
6. Test for water tightness to ensure no leaks
7. Place the trim plate back on, and secure it with the trim plate securing nuts
8. Push the handles on, and tighten the set screws

Follow these steps carefully to successfully replace the cartridges on your Artos F943-VO valve, ensuring optimal valve performance and functionality.