Here are a few basics  (Assuming GMAW short circuiting transfer)

Contact tube extended 1/8" beyond nozzel

Drag angle produces much deeper penetration than push

If machine has inductance control  start at the mid range and increase for a bit more punch at the root.  I'm usually more comfortable with higher inductance when doing open roots.

If power supply has two output lugs.. Choose the one that says "low" or "steep" slope for short circuiting transfer.  Use Flat slope lug for spray transfer and FCAW.

Stickout must be consistant,  a quarter inch increase in stickout during the weld can drop you almost fifty amps.  This can be and advantage if fitups are uneven.  Shorter stickout will provide more amps. If root gets a bit wide you can back off a small amount to reduce amps while wire and voltage remain constant.

Any oscilation *weaving* on a root pass must be minimal and kept within the area inside of the root gap.. Any weaving outside of this an you risk loosing your inside wedding band.  (NEVER WHIP)

(Assuming .035 solid wire) I like between 180 and 205 ipm and 17.5-19 Volts.  If the arc sound becomes soft and ploppy or you begin to see the end of the wire balling, reduce voltage by 1/2 volt incraments.

Is pipe rotated?

If yes.. Does your WPS require vertical travel to be uphill or downhill?