The top plate is designed to fit into the overflow inlet block which sits on the telescopic pipework.
This means that the top plate only goes down as far as the telescopic pipework does.Therefore, with a smaller grain bill under 4kg (8.8 lb) the top plate will sit a bit higher than the grain bed.
The best thing to do is to fill it with a bit more water until you see the water reach the top plate.
You will need to use the micro pipework. There is a specific calculation in the instructions for when you need to do this.
You can also find this calculator on our website, recipe creator or app.