Cuff:
If the cuff is leaking air you will hear a hissing sound coming from the cuff. Depending on the size of the leak, it can be easier or harder to hear. In this case the cuff needs to be replace. If the cuff is not under warranty, please call Zewa customer service at 1-888-993-3592 to purchase a new cuff. 

BP Monitor:
If you can not hear any sound from the cuff than the air leak is inside the BP monitor. In this case you will have to send the BP monitor to our service department to be checked.