Tricky situation with HVAC contractor

I didn't know where to post this. Its HVAC related, but its not that I am asking for DIY help. I had the HVAC co. that installed my furnace out at the end of the last heating season to repair a condensate leak in my furnace. At the time it was under warranty. They replaced a part that they felt would cure the problem. That day I ran the furnace for a few hours after the replacement and the "leak" appeared to have been fixed. However, since that day we have not run the furnace for months and the furnace labor warranty has since expired. I am concerned that the condensate leak didn't appear that day it was fixed since it was warm outside when we were testing it. I fear the leak may still surface if its cold outside where condensation would form. Anyway, what I am asking here is if the leak were to occur again.... do you feel that any labor involved in repairing it should still be covered under the expired warranty since they were initially out during the warranty period for this same issue?