To activate the warranty you have to send the core (old part) back to us within 15 days from the delivery date , 

we usually provide a free core return shipping label at no cost to the buyer ,

the core must not be broken , damaged or missing parts to activate the warranty. 

it is a 3 months warranty on the part only no labors. if any leaks after 1 month from the purchase you can get a replacement part (buyer pay for the shipping back and forth ) .