We are a group of employees working at a National Park for a sub contractor who keeps promising to fix the problem, our dorm has General Electric Zoneline 3000 heat pumps, of a total of 6, 3 do not work. Temperatures outside are well over 100. We have reported this but nothing... anyway... we will fix them ourselves if we can but we need some direction from someone who can guide us.
Here are the symptoms... While turned on, nothing but warm air comes out on the ac setting. Any ideas where can we begin?
Any help will be appriciated.

If you are not a service tech take a class. There are way to many items that can cause what your symptoms are. In cases of sealed system you need a EPA certificate to work on them. Sorry