HRM Dual Heart rate stuck at 72

I have the HRM Dual. I just bought it two weeks ago. I've gone on about 9 runs with it. During my last run, it worked perfectly for about 45 minutes and then my heart rate descended to 72. It has not moved since. It has been several days and it is very clean. It has no problem hooking up to my phone via bluetooth and connects just fine as soon as I strap up. However, the heart rate is stuck at 72 and doesn't move. Any ideas?

  • I would also question why with the previous strap I never had any issues in two years of use and with this one I already had problems

  • Hi guys, after about 5-6 months and many runs my HRM dual is stuck at 72 or 73, and basically it's not working anymore. Same both ant+ and bluetooth, I tried with runkeeper + iphone, always stuck at 73. It's not the fenix5, because it's working ok with the running dynamics pod.

    I also tried another battery with no success. Any solution to this? I'm going to ask for a replacement.

  • Any solution to this? I'm going to ask for a replacement.

    Yes. Do that.

  • Asked for a replacement, coming on this tuesday.

    Anybody knows is if the last production batch has a more reliable revision, or it's just the same? It worked very very well since yesterday, the strap looks perfect even though I've done runs for about 700km, I don't really know what's could be, but probably something related to the overall quality of the product.

  • So, I got my replacement.

    This one is Rev. C, the old one was Rev. B, let's hope they fixed the problem in the new one. I'll keep you updated.

  • Exactly the same problem.  It work first 2 trip now stuck on 72bpm!  New battery also.  I'm going to try clean the strap, use a COTTON t-shirt use it with ultrasound gel and shave chest area.  Also will try wearing the monitor at the side of my ribs and will give it all a damn good clean.  Keep you posted.

  • I bought the HRM-DUAL recently (August, 2020) and have had a variety of problems when using both the Bluetooth and ANT+ connections simultaneously.  I am posting this here in case others come looking for similar symptoms.

    I have 2 ANT+ devices (a Garmin Forerunner 35 watch, and a Garmin Edge 25 cycling computer) and one Bluetooth connection (iPhone 11).

    If I do not connect the Bluetooth and use only the ANT+ devices the HRM-DUAL seems to function completely as expected.

    But if I also connect the Bluetooth, I get a variety of problems symptoms.  On the Bluetooth connection, the sensor transmission gets “stuck” - apparently stops transmitting at random times unrelated to activity.  And worse, on the ANT+ devices the connection disappears and cannot be reestablished.  In this situation, on my Edge 25, I tried removing the ANT+ connection and then to re-pair it.  The Edge 25 refused to pair this sensor or any others.  I had to factory reset it to get it to pair again.

    My solution is to run without Bluetooth connections, and I am happy this way – as I don’t really need the iPhone connected – it is happy to get data through Garmin Connect.

    I want to note that there are many other online postings of unhappy users with similar symptoms – “stuck” or stopped transmission as well as an inability to connect.  See, for example, all the many negative reviews on the Amazon site.

    My conclusion is that there seem to be bugs in the sensor firmware when using both ANT+ and Bluetooth simultaneously, which or course it is designed to do correctly, and one of its primary selling features.

    Other posters have said upon reaching out to Garmin they were told to replace the sensor battery, even for brand new devices, and this has not typically made any difference.  And no one has posted a solution or resolution.

    As to sensor firmware, I wonder if there have been different versions over time, or perhaps updates that might have been done.  There is no way I can find to query the version or other data about the sensor firmware.

  • I'm on my second one after replacement because of this issue (and others). Same again... It's a design fault, likely in code. Just like my Edge 530, glitch after glitch after glitch.

    I make sure I detail 'featuring dodgy Garmin data' on every affected ride on Strava.

    Garmin don't seem to care.

    (p.s. even this website glitches!!!)

  • Thank you - this seems to be the solution for me.

    HRM was connecting via bluetooth to my phone and via ant+ to my Edge 830 - obviously it must have been confusing the poor little thing. 

    I removed the bluetooth/phone connection (forget device) and now two rides in it is working flawlessly again.