I have a Sportline solo 915 any touch heart rate monitor that I have been using for about a month now. My only complaint is that it will beep like crazy after about 15 or 20 minutes, then it stops reading my HR.
It is probably set up for a minimum & maximum heart rate. When you are out of that range it beeps. Probably you can go to their website, or type your model # in a seach engine, and the manual is online. I have the Timex hr monitor, and I had the same problem at the start, until I changed the setting, so the beep is shut off. I also changed the minimum and maximum heart rate setting also (but that wasn't necessary after I shut off the beep).