preventing a HP LJ 5100 Printer from chaning trays

[rolfea]

I'm not sure if this is a genuine problem or just moaning staff, but we've recently had someone put on a maintenance kit on our HP Laserjet 5100, and they said they had to reset all the settings to default.

 

Now the staff in the main office are complaining when tray 3, containing normal plain paper, is empty it automatically starting printing from tray 2, containing letter head.

 

Is there a way of preventing this change?

 

Thanks in anticipation.