HRM Issue
I had that happen with my Garmin HRM. I have a couple devices, so I was able to narrow it down to being the strap (new battery didn't fix it, and both devices would report the errors). I emailed Garmin and they sent me a new strap for free although my warranty was done. Perhaps send off an email?
Miles of Life --- Powered by MarkyV
I have the Timex Bodylink, and this has happened to me when I don't moisten the the electrodes on the strap, especially in dry conditions. Before putting the strap on, I wet the electrode surfaces down. Hope this helps.
Matt
I have had my Polar for about 2 years and it seams to give flakey readings every once in awhile. I find it is usually right when I start and withing the first 5 minutes sometimes it will read 220 and sometime it will read in the 80's and I know it it false either way. But after it has been going for a few minutes it usually locks on and stays there. I noticed it used to happen more before I changed the battery in the watch. You might want to try that.
Even with coded straps that are supposed t eliminate feedback and catter from other HMs they will sometimes react to security systems, electric trolley cars etc. Usually only for a sec - I have a POlar and can usually rectify it quickly by bringing the watch up to the strap to re-engage the signal.



Just wondering if anyone's come across this.
I've got a Timex Bodylink system and lately the HRM's been acting up on me - for about half of my runs it will peg out at 240 (my max hr is low, around 186 so I know it's not right, ha!), occasionally it will drop back down to a correct reading but it's been freaking out more and more often as time goes on.
When it first started happening I figured it was a low battery but I've replaced the battery and it hasn't helped.
Anyone experienced a similar problem with either a Timex or other HRM?