The township controller shall countersign all warrants upon the township treasurer, with the form of the warrant to be prescribed by the board of commissioners, but no warrant shall be countersigned unless there is sufficient unencumbered money in the respective appropriation item to pay the same. Whenever a warrant on the treasurer shall be presented to the controller to be countersigned, the person presenting the warrant shall, if the controller requires, produce evidence that:
53 P.S. § 56104