Forerunner ® 301 Owner’s Manual 49APPENDIX > H EART RATE MONITOR INFORMATIONTroubleshooting TipsIf you have trouble pairing, or if your heart rate reading iserratic, try the following suggestions.• Clean the sensors on the heart rate monitor. Dirt andsweat build-up on the sensors can weaken heart ratesignals.• Reapply moisture. Use electrode gel, water, or saliva.• Make sure the heart rate monitor is snug againstyour body. If you have trouble with erratic readings,position the transmitter on your back.• Wear a cotton shirt, or wet your shirt. Syntheticfabrics that rub or flap against the heart rate monitorcan create static electricity that interferes with heartrate signals.• Make sure the Forerunner is within 90–110 cm(35–43 in.) of the heart rate monitor.• Reset the heart rate monitor as described on page 38or turn the Forerunner off and then on again.• Locate and move away from sources of interference(see the previous page).• Replace the heart rate monitor battery (if you haveused the heart rate monitor for a few months).