I never got the HR clip to work on my Computrainer from day one. You can get an adapter from Computrainer to read a Polar chest strap.

Or, you could start training based on power output instead of HR...

Set the display on the 3D screen to show power and hold power to certain levels during your workouts. I.e., 150 for easy aerobic; 200 for hard tempo, etc.

Yeah I have the same problem when I start to sweat hard. Weird. OK you 3-4 hour at a time computrainer fanatics -- what's the fix?

Simple: Wear a Polar heart rate monitor, or get a PowerTap Pro and wear the HR monitor that they supply with the unit.