(plaintiffs suffered windstorm damage to farm buildings and sought recovery under insurance policy; policy excluded coverage for damages resulting from faulty or inadequate maintenance; defendant refused coverage under exclusionary clause and instructed plaintiffs to have appraisal done pursuant to appraisal clause in policy which applied if parties couldn't agree on claim; plaintiffs sued claiming that appraisal clause inapplicable and on basis that exclusionary language also inapplicable; trial court ordered appraisal to be conducted; reversed on appeal because factual issues remain over meaning and application of contract clauses, causation and liability).