Display error

The blood pressure monitor will display an "err" error message for many reasons. It could be the cuff is too small for the arm or wrist. Most wrist monitors measure up to 8.5 inches & arm monitors measure up to 13 inches. If a larger size is needed, then check with a pharmacy for larger sizes. Sometimes placement of the arm is wrong or the tube is not lined up correctly on the arm or the tube is not sealed tightly into the monitor. Sometimes body movement during a reading can cause an error. It is best to check if any of these occurrences happened before the error message occurred.