how to use timer and updatepanel without postBack

if you put the usercontrol within the update panel it will also update it.

if you don't want to update it on timer control put it outside the updatepanel.

no man its async postback. check that code by running you will see the browser will not refreshed everytime. it will automatically do the action. means the page is not fully postback.
when ever we put some control within updatepanel it become asnychronous.

Refer to this link it may help you:

http://www.c-sharpcorner.com/UploadFile/364074/timercontrol-with-updatepanel-in-ajax-using-Asp-Net/