Water Hammer and Boiler Pressure

WCF

I just moved into our house which was built in 1933 and has a single pipe steam heat system. The boiler was replaced two years ago with a Burnham V87 and few vents, if any were replaced at the time.

I have a couple of questions about the system. First should the pressure be set at 4 psi as it is now, or should it run at 2 psi?

Second, I've had ongoing problems with one radiator in a zone that has 3 radiators in the same room on one main. This one seems to fill with condensate and have to be forced out under pressure. It tends to hammer and sputter some condensate until the themostat is satisfied. This radaitor had a newer Hoffman 75 valve on it. The other two in the room had two different generations of the same Hoffman valve. My whole first floor has these valves on the radiators.

So here is what I've done so far. I replaced all the vent valves with Gorton #6 and the main on the zone with a #1. I checked the slope of the radiator and it was fine. There is no hand valve on it so that not it. I removed the radiator and flushed with water. It was clear and flowed through fine. After reinstalling it, it still has the problem. The only thing I could see was a slight leak just below the vent valve port (slight bubbling when some of the condensate hit the area). Could this be my problem?

Thanks

nicholas bonham-carter

pressure question

4 psi is too high. the whole system would behave better if the pressure were lowered to 1.5 psi, and would even be more comfortable and economical at 8 ounces! i am sure that the condensate is being raised up in the returns high enough to flood the radiators, because of the high pressure.

the hoffman 75 is a mainline vent, and not suitable for radiator use. it has difficulty functioning at pressures above 2 psi. the ideal venting scheme is described by boilerpro in his article:

[url=http://www.heatinghelp.com/forum-thread/128521/A-Very-Interesting-Article-by-Boiler-Pro]http://www.heatinghelp.com/forum-thread/128521/A-Very-Interesting-Article-by-Boiler-Pro

nbc