Customer reported PTAC unit in room above garage not cooling. Tech walked up to unit and saw it not running although control was set to cooling. Adjusted control and setpoint. Unit did not respond. Removed panel. A few seconds later, system started and ran in cooling by itself. Blower will not run at low speed. Blower shut off when set to low speed. Tested heat mode. Heat strips will run with blower off when set to low. Blower runs in high when set on high or auto. Compressor was still running in cooling mode with blower shut off while control is set to blower low setting. Blower does seem to run correctly when set to high or auto. 20 year old Fedders PTAC unit was manufactured in 2004 and uses R22. Tech diagnosed faulty PTAC control board not energizing low blower speed correctly. Due to age and likely cost of repair vs replacement, tech recommends replacing 20 year old PTAC unit. Need to call back with PTAC unit replacement quote. Wall sleeve exterior measurement is 16*42. See