(1)  An "installment contract" is one which requires or authorizes the
delivery of goods in separate  lots  to  be  separately  accepted,  even
though  the  contract  contains  a  clause  "each delivery is a separate
contract" or its equivalent.
  (2) The buyer may reject any installment which  is  non-conforming  if
the  non-conformity  substantially impairs the value of that installment
and cannot be cured or if the non-conformity is a defect in the required
documents; but if the non-conformity does not fall within subsection (3)
and the seller gives adequate assurance  of  its  cure  the  buyer  must
accept that installment.
  (3)  Whenever  non-conformity  or  default with respect to one or more
installments substantially impairs the value of the whole contract there
is a breach of  the  whole.  But  the  aggrieved  party  reinstates  the
contract  if  he accepts a non-conforming installment without seasonably
notifying of cancellation or if he brings an action with respect only to
past installments or demands performance as to future installments.
Structure New York Laws
Part 6 - Breach, Repudiation and Excuse
2-601 - Buyer's Rights on Improper Delivery.
2-602 - Manner and Effect of Rightful Rejection.
2-603 - Merchant Buyer's Duties as to Rightfully Rejected Goods.
2-604 - Buyer's Options as to Salvage of Rightfully Rejected Goods.
2-605 - Waiver of Buyer's Objections by Failure to Particularize.
2-606 - What Constitutes Acceptance of Goods.
2-608 - Revocation of Acceptance in Whole or in Part.
2-609 - Right to Adequate Assurance of Performance.
2-610 - Anticipatory Repudiation.
2-611 - Retraction of Anticipatory Repudiation.
2-612 - "Installment Contract"; Breach.
2-613 - Casualty to Identified Goods.
2-614 - Substituted Performance.