When I plug the treadmill in and put the safety magnet on the treadmill constantly goes up and down and the display looks as though it's in some preset mode

The treadmill will not run if you remove the safety magnet. Replace the safety magnet and reset the treadmill. Should start working again.
Thanks.

I’m happy to assist further over the phone at https://www.6ya.com/expert/christopher_722ea729aae6fd07

downlod the instr. manual and see how to start. go to

www.fitness.manualsonline.com
normally the safety key, is in the display board down in the midlle at panel.

God bless you

I have a healthrider h120t when i put the magnet it beeps once and everything all the displays stay on zero but nothing moves

Renee, Here is how to recalibrate the incline motor. Read all of it It will be good to keep.
Plug in your treadmill, do not stand on the walking belt. Hold down the "Stop" and "Speed +" key and insert the safety key or magnet, let go of the two keys. Now press "Stop" key once. This puts you into the level 2 of calibration. Press the "Speed +" key slowly until you see 85 on the console, (at this point the display is going to show the percentage of motor usage and also the actual walking belt speed) at 85% motor usage your top speed should be between 10 and 10.5 MPH or (of 12 and 12.5) depending on the treadmill. You must know your treadmills top speed. (Important the motor may be damaged if you set the maximum speed higher than the maximum speed that your treadmill is made for). If the speed is higher than 10.5 or 12.5 then you need to turn the potentiometer down to the correct level. If the speed it to low you need to turn the potentiometer higher. Once the speed is correct you are done calibrating the speed. Press the (-) speed key to lower the percentage to (0). Next press the incline (+) button, this will make the incline motor go all the way to the maximum incline and come all the way down to the level position. Then remove the safety key and the treadmill will reset into the normal manual mode, when you re-insert the safety key. Matt

If you need further help, I’m available over the phone at https://www.6ya.com/expert/matt_8dbc24bf722649ac

http://www.youtube.com/watch?v=E-q-uS4t6so
Ensure that the treadmill is plugged into a grounded outlet using the correct surge suppressor. Use a UL 1449 suppressor listed as a transient voltage surge suppressor (TVSS). It must be rated for 15 amps and 120 volts AC. Secure the services of an electrician if the outlet is not grounded, or move the Proform treadmill near a grounded outlet. Do not use an extension cord.

• 2

Insert the safety key fully into the display. Treadmills with keys are designed not to turn on without the safety key in place.

• 3

Find the circuit breaker on the front of the frame and make sure it is not tripped. The circuit breaker is a vertical switch on the 540S and a horizontal switch on the 540 Interactive Trainer. Press it to the "Reset" position, which will be labeled.
2. Reed Switch

o 1

Unplug the treadmill and remove the safety key.

o 2

Move the upright base of the treadmill down with the help of another person and lift the uprights so that you can get to the underside of the console. Use a Phillips screwdriver with at least a 5-inch shaft to remove the screws. There are five hood screws on the 540 Interactive trainer and four screws on the 540S.

o 3

Remove the motor hood to get to the small reed switch by pivoting the hood off the frame. Find the reed switch and magnet, which are on the left side of the pulley for both models.

o 4

Turn the pulley with your hand until the reed switch aligns with the magnet. There should be 1/8-inch gap between the two. Fix the distance so that it is 1/8 inch by loosening the reed switch screw and sliding it to the correct distance. Tighten the screw.

o 5

Reverse the directions to put the hood back on and the treadmill upright in the original position.


Watch this videos:

First thing I'd try is just using any magnet. I'm sure that's all the key is normally. If that doesn't work, no you cannot use a treadmill without a key. It's a safety measure created by the company.
Here's the key for sale on amazon that goes to your treadmill.
http://www.amazon.com/Pro-Form-Treadmill-Safety-Key/dp/B002YP4KQE
Hope this helped!

Watch this video and Step:
http://www.youtube.com/watch?v=E-q-uS4t6so

Ensure that the treadmill is plugged into a grounded outlet using the correct surge suppressor. Use a UL 1449 suppressor listed as a transient voltage surge suppressor (TVSS). It must be rated for 15 amps and 120 volts AC. Secure the services of an electrician if the outlet is not grounded, or move the Proform treadmill near a grounded outlet. Do not use an extension cord.

• 2

Insert the safety key fully into the display. Treadmills with keys are designed not to turn on without the safety key in place.

• 3

Find the circuit breaker on the front of the frame and make sure it is not tripped. The circuit breaker is a vertical switch on the 540S and a horizontal switch on the 540 Interactive Trainer. Press it to the "Reset" position, which will be labeled.
2. Reed Switch

o 1

Unplug the treadmill and remove the safety key.

o 2

Move the upright base of the treadmill down with the help of another person and lift the uprights so that you can get to the underside of the console. Use a Phillips screwdriver with at least a 5-inch shaft to remove the screws. There are five hood screws on the 540 Interactive trainer and four screws on the 540S.

o 3

Remove the motor hood to get to the small reed switch by pivoting the hood off the frame. Find the reed switch and magnet, which are on the left side of the pulley for both models.

o 4

Turn the pulley with your hand until the reed switch aligns with the magnet. There should be 1/8-inch gap between the two. Fix the distance so that it is 1/8 inch by loosening the reed switch screw and sliding it to the correct distance. Tighten the screw.

o 5
Reverse the directions to put the hood back on and the treadmill upright in the original position

Chech: Optical Sensor if have it.

I would think that it can't hurt anything to try another magnet but if you end up needing to buy another one here is one website that sells them: Sportsart TR20F safety key

First, check and make sure the safety magnet is in the correct place. If not, place magnet. If it is, then the safety magnet sensor, sensor cable, or the console is messing up.

i just called the manufacturer on this and found out i have a faulty control panel, but these are the steps they told me to go through to reset. If it works, then you are good, if not, you may also have a control panel issue.
1. plug in and turn on treadmill, keep red key out
2. press and hold the stop button and speed up button at the same time and hold them while you insert the red key
3. after red key is inserted, let go of both buttons
**CAUTION - be sure to stand on side bars of treadmill, clear of the belt for this next part bc it will go VERY FAST***
4. press stop button once
5. press speed up button until it reads 85 (see what i mean?!)
6. press stop button once
7. press incline down or up one time and it should get back into normal mode. mine just started a series of flashing lights and "8"s in all the "windows" so my panel needs to be replaced. here is the number i called - 1-877-993-7999. Good Luck!