Hi, I used my 810 for the first time yesterday. I had the heart rate monitor strapped to me, it has a new battery so all okay there. I then tried to pair with my 810 and received the same message a few times, "HR not discovered" or words to that effect... There was no HR data showing in the heart rate monitor field on the Garmin screen, however, when i uploaded my ride to Strava the HR info was all there, so it is just not being displayed on the 810. Has anyone experienced this, is there a known fix? Thank you for any help.
Well there's your problem. No past or current Garmin cycling device will pair with a Bluetooth sensor. They're ANT+ only. So wherever the HR came from, it wasn't your 810.