Down payment question

[Nik Moushon]

Still new to 1031s so excuse what might be a easy question to answer. I'm struggling understanding how to determine what you can buy with a 1031. I know the purchase price has to equal the sell price or greater but I'm confused on what is used for the down payment of the new building. Say I sell for $500k but have equity to loan at 50/50. So I have $250k cash and $250k loan left. Even though I have to use the whole $500k valuation for the 1031 purchase I can only use the $250k cash towards the down payment right and refinance the old loan into the new loan for the new purchase?