Just looked at a boiler replacement candidate. Their gas consumption skyrocketed three years ago, and they had a hard time finding a contractor to deal with it. Local contractor thought it was hot water, but begged off when he found it was steam. Large tank above boiler looks like an old style expansion tank, but is a DHW tank (no heat exchanger) with (I believe) an immersed coil feeding it. The building cold water still passes through this, just before entering the upright water heater.
The boiler (Iron Fireman) has the sight glass inside the jacket, with a factory cutout for viewing, and an old red Hoffman water feeder (#4?). I am told it was originally coal fired. The house was built in 1911, by a rich family , in a small Midwest town. It has a really old Burks condensate pump and tank, that may be original. The radiators are all trapped. To their knowledge, nothing has ever been done to the traps. There are no vents, except the open condensate tank vent pipe.
I believe the last of the traps failed, leaving the heating, mostly, to the mains, which are completely uninsulated (this is what heats the basement). The lower water line of the new boiler leaves plenty of height for gravity return, and all the returns are in the basement ceiling. My question is this: Is it possible to eliminate the condensate tank, and just use the gravity return? I know that doing so would require piping in a vent (Hoffman # 75). What if I put a # 76 in? Could I transform this 106 year old, pumped return system, into a gravity return, vacuum system?
Please give me some guidance, guys.