I am using the station to remove switches, jacks, usb connectors, etc. from a bluetooth transmitter PCB, in an effort to slim it down for a project. I don't know how I am supposed to keep the solder molten, remove the component and regulate the temperature of the PCB so that the rest of the components on the board don't suffer. I am using the smallest nozzle, and have used temperatures in the ranges between 250-350 degrees celsius, all to no avail. The board is around 5x5 cm, so it heats up quite fast despite my efforts (so much so that I can't touch it - is this normal?)
If the components that you want to keep in the board are beeing blowed out from the board, I'm sure that you will agree with me that there are two concurrent reasons: the solder of those components is melting, AND the blow over them is too strong.
Sometimes, it's possible to use aluminum adhesive tapes, or kapton tapes, for protecting the solder of the components that should not be dessoldered.
But, many times, it is impraticable keep the solder of the components that will stay on the board from melting. In this situation, the way is to reduce the blow over those components, in order that, even if their solder melts, or soften, those components stay in their place.
If you want to dessolder only some of the components, but all of them are being blowed out from the board, probably you are approaching the nozzle too much to the board; keep the blower away, but, pointing to the board. It will take more time for the board heat up. Let the board and the components heat slowly.
Don't take the use of the smaller nozzle so seriously. Try with bigger nozzles; If the nozzle is smaller, their blow is stronger (and you don't want a strong blow that wipes everything from your board).
Gently blow the hot air to the board, slowly, until the solder melts; then you take that undesired components out, with a tweezer. If the blower is at a correct distance, the components that you will keep in the board will not change their position.
Practice with scrap electronics. If you have a multimeter with a bi-metalic thermo pair (for temperature measuring), put the sensor at the board (this is a very good learning practice), managing the slow heating of the board untill the melting point of the solder.
It is absolutely normal that you will not be able to touch the board. But you are not trying to hold the board with your bare hands, are you? The board has to be fixed to a support for this procedure.