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Initially, it possibly have airlock in the pump and water intake system
Try to manually prime your machine, for instruction CLICK HERE it supports all gaggia and seaco models. Manual hand pump is sold separately, you can order it HERE.
If still, sometimes you need to get rough on your machine in able to remove the clog air on water line. slamming the water tank into machine sometimes help. If still, unplug your machine, remove water and turn the machine upside down or shake your machine if possible.
Let me know if you still have questions.
Hope this information will be helpful.
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