steam trap size

lb./hour x safety factor=120 x 3=360 lb/hour load on trap.

Then consider pressure differential across trap.

do you always have 6psi at the equipment inlet? Or is there a control valve between the supply steam and the steam kettle?

If you have a control valve size the trap for 360 lb/hr with 1/2psi pressure differential across the trap.

With no control valve size the trap for 6psi differential

Both the above examples assume that there is 0 psi pressure (no back pressure) in the condensate return.

Either way a Watson McDaniel 3/4" F & T trap is rated at 440 lb/hr at 1/2 psi diff would do it.

3/4" 15PSI trap is more than enough. We make traps for many OEM jacketed kettle companies like Blodgett, Manitowoc, Market Forge, Groen and they use a 1/2" radiator trap or one of our compact traps which have far less capacity.