Flow Test Procedure

To check flow accurately we need to take the pumps out of the equation. Put the machine in manual mode. 

Run the pump for 5 seconds (right brew button) Run pre-infusion for 5 seconds (left brew button) Place a cup on a scale under the group, tare and weigh 10 seconds of pre-infusion only on both sides. These should be with 0-5g of each other.

If they are the same and you still get more/less coffee out of one group you may have the pump for that group set differently.

To rectify this, confirm which pump you need to adjust by running only the pump button and visually seeing which pump is on via the gauge. Place coffee in the portafilter, (this is important to get the correct pressure) lock it in and run the pump button. Adjust the pump by unscrewing the black plastic lock and turning the brass adjustment on the pump head as below. By placing coffee in another group and running the pump you can see on the gauge where the pump is set to in order to make the different pumps match.

Also worth making sure your baskets are the same size and that one isn’t vastly older than another.