§ 317. Determination of contested claims for compensation. A civil defense volunteer may file with the board a notice that his claim for compensation under this article has not been paid, and the board shall have full power and authority to determine all issues in relation to every such claim and shall file its decision in the office of the chairman. The decision of the board shall be final as to all questions of fact and, except as provided in section twenty-three, as to all questions of law.