Proper presser foot height can contribute greatly to the sew quality of the machine. Look for the following issues when troubleshooting a thread break.
Presser Foot Set Too High
If the presser foot is set too high, you may see more material movement and a loss of design registration. This is often accompanied by thread breaks.
Stop the machine and adjust the presser foot. See how in the presser foot section.
Presser Foot Set Too Low
While rarely does this create a thread break, having the presser foot too low can increase the sound of the machine as it sews. It can also create a faint light halo around the design on a dark garment. This halo can usually be removed with steam, water, or a light ironing aid.
Stop the machine and adjust the presser foot. See how in the presser foot section.