HRM Pro struggling to keep connection

I picked up a secondhand HRM Pro last week from CEX, so it has a warranty, but as they test everything before sale I wasn't hoping to need to use it..

However I've had very poor results both running with my Garmin Fenix3, and on Zwift using AppleTV.
The unit can't seem to maintain a connection for very long.
I replaced the battery last night, and I've still had issues today, so wondered what other options I can take before returning it?

I've previously been using my original HRM Run strap which came with the Fenix3 back in 2015. It's never missed a beat, and aside from having to buy new straps and change the battery, I can't fault it - but after my laptop died, and I got an AppleTV to use Zwift instead; I wanted a HR strap that can connect via Bluetooth, since the old HR unit was just Ant+.

I suffered about 5-6 drop outs within an hour on it's first use with Zwift last week - which was a real pain as the Wahoo Headwind kept cutting out too.
And then I went for a run at the weekend which was fine.
But then I've gone on 2 runs this week, and it's not been able to hold a connection. The run today was with a new battery too, in case that was an issue.

It seems to connect to the Fenix, and then instantly lose connection again, and again - repeatedly.

For my last 2 runs, it's connected for a second, showing 72bmm, and then disconnected. It might then reconnect and show my actual HR, but then disconnect again, and reconnect back at 71bpm.

I don't know how it's connecting to the Fenix via Ant+ or Bluetooth, is there a way to find out? But the issue with AppleTV and the fact that it struggles to stay connected to Garmin Connect on my phone, makes me think it's a Bluetooth issue.

As I understand, the HRM Pro is meant to be able to store data too, but attempting to download offline data afterwards does nothing either.

I always wet/lick the connection pads before putting on, and that works fine on my old strap; but even fully submerging this before a run doesn't seem to make a difference.
I tightened the strap too, but that didn't help. Been a wearing HR strap for activities for past 8 years, so it's not a new concept to me.

I've tried unparing, removing from device and re-pairing again...

Garmin Connect says it's on Firmware 8.8 and says that's most up-to-date version.

Anyone have any other suggestions please, before I return it?
Thanks!

First use, on Zwift:

First run, which was fine:

Second run, disaster:

Today's run, bigger disaster, with new battery:

https://imgur.com/c0Sg6nu

0 InsolentMinx 5 months ago

I seem to have fixed this by completely soaking the strap before use and adjusting the strap so it's not too loose and not too tight.

Just licking the contact patches (like i used to do with my HRM-Run for the past 9 years) obviously doesn't work with the HRM-Pro.

So running under a tap, and soaking completely seems to be the solution

0 S.M.R. 5 months ago in reply to InsolentMinx

Not had an issue with my HRM-Pro at all. Just put it on and go. Sometimes done even wet it at all. And I see you did try removing it completely from the device and reconnecting it. So interesting how we have so many different experiences with the same devices. I have the Pro-Plus now and that also works great for me.

I see the FW I have is 8.9 on the Pro Plus just FYI. Fairly recent update i think. (Sometime late August I think looking back at some activities)

0 InsolentMinx 5 months ago in reply to S.M.R.

Yeah it's weird how for some it works fine, and not so for others.
Typically I spoke too soon, and for some reason it wouldn't connect at all to my watch today after i gave it a thorough wash on Monday night

0 eezytiger 5 months ago in reply to InsolentMinx

Try wetting your chest instead of (or as well as) the strap. The strap doesn't hold the water very well on the electrodes. What you need is wet (simulated sweat) skin. Wetting the strap is just adding a belt to the braces. It can do no harm, but what you actually want is wet skin that stays wet until you sweat.

0 philipshambrook 5 months ago in reply to InsolentMinx

InsolentMinx said:
So running under a tap, and soaking completely seems to be the solution

It is. Thoroughly soaking the strap (I use warm water for obvious reasons!) puts plenty of moisture into the mix. Just wetting the pads is ok but since the pads do not retain water, it is not a reliable process. Soaking the strap wets the fabric of the strap and provides moisture to the electrodes. Besides, since most people use saliva it's also not a very pleasant experience!

0 amazanto 3 months ago

I'm having problems with my HRM Pro Plus as well, I got mine replaced but nothing changed. I think these problems have something to do with the software.

0 InsolentMinx 3 months ago in reply to amazanto

Mine was very sporadic still, so in the end i just bought a Wahoo Tickr-X. It was a fraction of the cost, and works much better.

Still has running dynamics too, as well as a storage memory, so I don't feel I'm missing out on much.

0 Strizzle 2 months ago in reply to amazanto

What issues were you having? I'm also having frequent issues with my HRM Pro Plus connected to a forerunner 945lte and Garmin is shipping a replacement now. It worked great for 6 months being used twice/wk and has been unreliable the last 6 wks providing poor heart data I changed battery, resynced to watch and tried the reverse polarity battery trick and it didn't help. I always wet it well pre run and clean it weekly. I tried my wife's Polar verity sense upper arm optical strap this morning doing 8×20second strides and it captured heart rate very well during all 8 strides.

It seems like it's software related with the pro plus, but Garmin doesnt believe it's software related. Fingers crossed this new strap works...otherwise, I'm switching to Polar.

0 amazanto 2 months ago in reply to Strizzle

I wear it connected to my fenix 6 pro. At first it was great (for like six months or so), there weren't any issues, then the running dynamics stopped showing and the heartrate stopped being accurate. I tried everything the manual suggests but nothing worked out so since it was still under warranty I got my strap replaced with a new one. The thing is I still have the same issues. No running dynamics, sometimes they don't appear at all, sometimes they partly appear. I mean, the dynamics are not fundamental for me but I paid for the strap and I want no issues with it. The worst part is that the heart rate stops showing during my runs. Garmin isn’t interested in solving the problem, they just replace the strap. Now I’ve changed the battery (even though it was OK) and - as someone suggested here - did the reverse polarity reset. Let’s see what happens.