If still unsure, check with your accountant.

You can just setup your credit line account like any regular bank account and name ("LOC" or "Credit line account" for example).

1. Create a new account in the Chart of Accounts and ensure the Account Class is Bank.
2. Name the Account as Credit line account.
3. You can select to do payments from this bank account as usual.
4. To transfer money to or from this bank account:
1. Select Banking.
2. Click on Transfer funds.
3. You can select to Transfer from or Transfer to bank name and enter the amount required.
4. Click Process.
   Note: This asset account will almost always have a negative value.