How accurate are the calorie counters on treadmills and cardio equipment?

There isn't a lot of difference between them. Cardio is all about getting you heart rate higher so Treadmill or Bike is often down to which you personally prefer. You could also use a rowing machine to get the same cardio workout.
The biggest difference is mostly which muscle groups your using to pump up your heart rate.

contact Bowflex this is not bowflex tech support

electricity problem,

Yes the repairmen is o.k when he says the controllers nothing to do with the calorie counter.
See the block diagram attached, the problem is the display board or upper board. However adjust the REED switch, test for open or faulty, clean it, and tigh very well the connector b) tight the ribbon cable for keypads inside the display board. c) replace batteries from display by new one, with the same polarity, same markay such hybrid rayovac. c) clean the contacts battery.
God bless you

If a cardiovascular workout is what you want, you should get an elliptical machine. They give you a total body workout - with handle bars for your arms and pedals for your feet. You can burn a lot of calories without having a lot of heavy impact on your joints.

Go to Gymparts.com they will have tech manual for this unit, but a technical schematic is never provided for any piece of cardio equipment it is consider proprietorial to the manufacturers.

Here is another source for the Landice L7 cardio treadmill key.

First you need to understand that the Polar system is a medical grade device and it is calculating calories based on specific information that you have inputed and heart rate data from your heart.

Most treadmills and other exercise machines use a much simpler counter that is height and weight based to calculate calories and are generally over generous with their numbers.

Depending on the blood pressure machine you are using, the pulse (not heart rate) is coming through the brachial artery, again not quite as accurate as measuring r-r variance from your heart. There is a ton of literature you can read if you are into the accurateness of the system, but I will sum up with saying that you actual calorie expenditure will be closer on the Polar than on most other devices outside of a hospital. As too the heart rate this is also true, so more likely you are getting inaccurate numbers from the other devices.

If you want pinpoint accuracy then you will need to use the Polar RS800 or S810 devices that measure and display true R-R.