Traps

I would like to pick some brains out there on f&t traps, I am working on an 1920's system that has two traps coming off of drip legs from the end of the main. these traps sit about 2" below the center line of the dry return lines. They operate as a bucket trap except that there is a thermostatic air vent on the top which feeds back into the outlet side of the trap. I want to replace these with Hoffman H series F&Ts with a check valve on the outlet. The outlet line would then be about 5" below the dry return. Do I need to put an air vent on the outlet between the trap and the check? Will these h series traps work well in this installation? It seems to me that hey should, without air vents, but this is the first time I have run into this situation where there needs to be a lift of condensate.