F&T trap replacement

JHK

Hello, I replaced a F&T steam trap for a coil that serves a drug store. The existing steam trap I would of just changed the guts but the strainer was on the outlet of the F&T trap so I wrote it up to replace the F&T trap. The original was a Barnes and Jones 2015-4 I put in a Watts WFT 1. I added a air vent to the unused inlet port it is a Hoffman 3/4” I do not remember the number and a Hoffman 62 vacuum breaker on the outlet side of the F&T trap with a test valve for the trap. The issue is when the thermostat satisfies and shuts off the burner and the blower, water comes out of the steam vent I installed for a few seconds and stops but it does it every time. I added the steam vent because there is minimal venting, there is only 1 other steam vent but I would not even try to remove it. It is a corroded mess at the end of the main on a tee on the run not branch. There have been discussions about re-piping the wet and dry returns.
Additional Info:
The supply at the coil is copper tubing brazed. The return at the coil is copper soft soldered.
The brass concentric reducer coming off the coil was supposed to be changed to a eccentric reducer ( it will be, there was a mix up with the supply house with that fitting.
Cut in .5 psi Cut out 1.5 psi.
The boiler is a small oil fired 3 or 4 section Weil McLain boiler that has been in for over 30 years. The wet returns have no tees to access the piping. All the fittings are 90s except for the Hartford loop tee.
There is no insulation on any of the steam piping ( which has been talked about on a number of occasions) and I have skimmed this boiler for hours on 2 occasions and it is only a little bit cleaner. I have not used chemicals because I was concerned about loosening up any scale or corrosion that maybe covering a potential leak.
Clearly a lot of issues with the system but I am concerned about the water coming out of the steam vent. The steam vent is valved off for now. Thank you.

EBEBRATT-Ed

Does this return line go to a dry return to a condensate receiver or into a wet return?

If it goes to a condensate receiver with a dry return I would remove the vent, the air will vent through the trap to the open vent on the condensate receiver.

If the return drops into a wet return then I would try raising the vent up as high as possible and keep the boiler pressure as low as possible

JHK

It goes into a wet return. I will raise it up, thank you