Spa drains when turned on

His is not typically a control panel issue but more likely a valve issue.

Your valves are set as follows wih a few minor variations.....
Pool mode- sucks from pool skimmer and or pool vac line and returns water to both the pool and spa.
Spa mode - self contains the spa , meaning water is sucked from the spa and returned only to the spa.
If your spa is draining then most likely one of your electronic valves is failing...most likely it's the return valve so what is happening is the water is sucked from the spa and returned to the pool instead of self containing the spa.
Easy check is to be next to the equip when spa mode is selected and two valves should move and align properly, the return side valve is most likely not moving or it is not moving into the correct position.
The fix is either adjusting the valve acuator or buying a new valve acuator.
Another thing to check is on the main panel circuit board to ensure the return and auction 3 pin plug ins are still connected.

You may have to open the valves and reset the cams. Not too tricky, just a lot of trial and error to get it just right
FYI when you decide to replace the actuators, Intermatic now makes a direct replacement for both Compool (Pentair) and Jandy models. They are significantly cheaper.

This sounds like the spa has been put in the Standard Economy mode.
When your spa is in this mode almost nothing works as it is in a freeze protection mode.
Change the operating mode back to standard and it should work just fine in the future.

US Parts Center

I need a manual to program the controller, how do I get one?

You cannot drain the spa using the indoor controller, unless the valves out at the equipment are set wrong. go to the outside pannel and put the system in" service mode"(using the button on the left). then push the button on the right till it says "spa fill".There are 2 "accuators" (or automated valve turners) They are black rectangular boxes connected to the water valves. Use the toggle switches on the side to turn the vales to the correct positions. You want the pump to **** from the pool and return to the spa. Now turn on the filter pump and let it run till the spa is full. Put the system back in "auto mode" and you are done.

If it has motorized valves the stop positions have to be adjusted so that the water coming back is equal to what it drains to stop the spill over process unless you want to add more valves but the pool pump does the job of heating and filtering the spa