Here's a reply to an old question:
The second parameter is a record, so you want to include your command and connection timeouts inside the record, instead of multiple separate parameters.
Thus, you would have:
Source = Odbc.DataSource("dsn=PostgresSql64bit", [HierarchicalNavigation=true, ConnectionTimeout=#duration(0,0,5,0), CommandTimeout=#duration(0,0,5,0)])
The two durations don't have to match. The first is for the connection (how long it takes to initially connect), and the second is for the command (how long it takes to run the query).