Timed refresh of input data

My workbook has web sourced input data. I also have a timer which shows the time elapsed since the workbook was connected to the data source.

Rather than refresh after regular intervals I want a macro code that is going to refresh the data when the timer reaches, say, "00:05:00".

With my primitive VBA knowledge I have tried something simple along the lines of If A1=TIMEVALUE("00:05:00") Then RefreshAll but it does not work.

Any thoughts?