Is It A Vacuum Steam System Converted To A Regular Steam System

Halfbreed

I have a project I'm bidding. All of the radiators have 3/4" steel pipe coming out of the floor and entering the radiators through the top port, with the return exiting out the opposite bottom port and going into a thermostatic steam trap. In the basement there are steam supply pipes with 3/4" piping branching off to the radiators and smaller return pipes with the radiator returns going back into them. The boiler is a year old Weil McLean Gas Stem with the pressure limit control set for 2 lbs of steam and there isn't a vacuum pump on the system, only a new return reservoir tank and pump installed. Main steam vents were replaced with steam traps at the end of the steam runs. I believe the original system was installed in the 1930's. Could it have been originally a vacuum steam system back then and converted to a straight steam system when the original boiler was replaced in the late 1950's with an oil fired one? From what I've been told it has never worked right in the past by the previous maintenance person to the property. While measuring the rooms and radiation to do a load analysis I noticed that all the bedrooms on the 2nd floor had newly installed baseboard electric heaters, which tells me they were having heat problems there. So, was this system originally a vacuum steam system or did they pipe it originally to be a regular steam system?

Jamie Hall

More likely to have been a vapour system. Can you find any names on the radiator valves? Or maybe send us a couple of pictures of what's there?

If it's a dry return system, and the steam traps you mention on the ends of the steam mains, it's possible that they are meant to be there and are actually crossover traps -- in which case the dry returns have to be vented. They should be anyway...

Steamhead

What type of building is this? if they still have the original plans, you may be able to look at them to see.

EBEBRATT-Ed

Check the EDR capacity of the radiators and look at the pipe sizes. Vacuum systems used smaller piping than regular two pipe systems.

If it was originally a vacuum system and is not now a vacuum system you could have isses at maximum load.