et
Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
#"Changed Type" = Table.TransformColumnTypes(Source,{{"CHP Overall Heat Time", type datetime}, {"HZI Total Heat Time", type datetime}, {"Boiler total gas used Time", type datetime}, {"Pasteuriser heat valve energy Time", type datetime}, {"Pot Ale heat valve Time", type datetime}, {"D1 heat valve Time", type datetime}, {"D2 heat valve Time", type datetime}, {"D3 heat valve Time", type datetime}}),
#"Unpivoted Only Selected Columns" = Table.Unpivot(#"Changed Type", {"CHP Overall Heat Time", "CHP Overall Heat ValueY", "HZI Total Heat Time", "HZI Total Heat ValueY", "Boiler total gas used Time", "Boiler total gas used ValueY", "Pasteuriser heat valve energy Time", "Pasteuriser heat valve energy ValueY", "Pot Ale heat valve Time", "Pot Ale heat valve ValueY", "D1 heat valve Time", "D1 heat valve ValueY", "D2 heat valve Time", "D2 heat valve ValueY", "D3 heat valve Time", "D3 heat valve ValueY"}, "Attribute", "Value"),
#"Added Custom" = Table.AddColumn(#"Unpivoted Only Selected Columns", "Custom", each if Value.Is([Value],type number)
then "Number"
else "Text"),
#"Added Custom1" = Table.AddColumn(#"Added Custom", "Custom.1", each if [Custom] = "Number" then [Value] else null),
#"Filled Up" = Table.FillUp(#"Added Custom1",{"Custom.1"}),
#"Renamed Columns" = Table.RenameColumns(#"Filled Up",{{"Custom.1", "Data"}}),
#"Filtered Rows" = Table.SelectRows(#"Renamed Columns", each ([Custom] = "Text")),
#"Removed Columns" = Table.RemoveColumns(#"Filtered Rows",{"Custom"}),
#"Renamed Columns1" = Table.RenameColumns(#"Removed Columns",{{"Value", "Time"}}),
#"Grouped Rows" = Table.Group(#"Renamed Columns1", {"Attribute"}, {{"Min Value", each List.Min([Time]), type datetime}})
in
#"Grouped Rows"