Article 4.19.1B : Ates change over not happening on both EB to DG and DG to EB
1) check whether customer EB and DG supply properly given or not.
2) check whether ATES is in auto or manual mode. if it is in manual ask them to change auto through remote. If it is auto 5th LED signal will ON. in manual it will be off.
3)check whether key is in auto or manual mode. if Key vertical direction then auto mode. If it is in Horizontal then it manual mode.
4) check whether both fuse are in good condition are not. check fuse condition fuse will blow or lead will broken. if it ok.
Some times panel builder will do testing at there office, so both EB and DG supply will give EB only. if Over voltage is >260 then it won't trip. output also won't get but input will there.
If every thing is fine then it will work. still it is not working may be controller issue at ATEs.
Note: if customer want operate through handle then guide them to make key in Manual mode other wise it will damages the controller.