John contracts with Fay to install a heating system in Fay's factory for a price of $30,000 to be paid "on condition of satisfactory completion." John installs the heating system, but Fay states she is unsatisfied and refuses to pay the $30,000. Fay gives no reason except that she disapproves of the heating system. According to experts, the heating system as installed is entirely satisfactory. May John successfully recover $30,000 from Fay?