While the refusal of the arbitrators to consider competent evidence,1 or irregularities in procedure which prevent a fair and impartial hearing,2 may be ground for attacking an award, such defects may be waived by the parties by acquiescing in the continuance of the arbitration proceedings or by taking advantage of the award with full knowledge of the facts.3 If the parties and the arbitrators begin the proceedings under a mistake as to the contract which controls the rights of the parties, the act of the parties in submitting the true contract to the arbitrators and acquiescing in further proceedings, operates as a waiver of such defect.4 The fact that the parties, with knowledge of the facts, accept the award, and that a part payment is made thereunder, operates as a waiver.5