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2 Pipe Steam Woes - Cold Zone Of House

Dubuquer Member Posts: 1
Hi guys, I'm posting here hoping to get some advice with a cold section of the house that I'm remodeling into a rental unit. I want the unit to be as comfortable as possible, and the heating currently in place is just not up to par. The main heat for the house is 2 pipe steam, and I have no issues with the main house. Granted, the main house appears to be original piping to the Boiler, and the rental is in an added on wing of the house and was done much later.

I've tried getting some advice from local heating companies, but I have had some serious doubt about their advice. One company advised me to put vents in my rads, which I am fairly certain is a bad idea on 2 pipe steam? The other company hasn't gotten back to me at all, even after 2 calls. I just am not sure if anyone is equipped to handle this issue in my area (Dubuque, IA). I don't even know if anyone will touch the pipes due to the apparent asbestos  slathered over them. I'm at the end of my rope here. I need to get this remodel finished and the other unit rented, but I don't have money to cover an asbestos mitigation job. I've done asbestos removal myself before, and I'm willing to tackle anything. I'm not new to working on plumbing, this is just my first steam system and I'm intimidated to say the least.

I attached some photos of my dilemma. I labeled the pipes and where they go. My main issue is with the labelled sections.

In the first photo, (A) is a main riser for the house. It continues into photo #3, where it branches off towards the rental unit (B). In photo #4, this is where I think there were changes made. (B) continues into the main house bathroom and kitchen. There are 3 Rads on (B). The branch into the rental unit, (C), continues into photo #5. (C) connects to 4 Rads, so 7 total Rads on this riser, and by far the longest distance in the house from the boiler.

Interesting side note, when I close off enough Rads in the main house, the rental unit Rads heat up just fine. Is this just a case of too long of a run from the boiler? Too many Rads on this riser? How do I fix this?


  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    edited March 2014
    Cold addition

    It's very unlikely that 2-pipe radiators will need vents on them. Those that do are very old, and probably confined to the east coast.

    If the system is properly balanced, then steam will arrive at each radiator at the same time. This balance is affected by the ability of main (not rad) vents to allow the air in the pipes and radiators to escape ahead of the incoming steam. Trace the path of the steam, and therefore as well the escape route of the air. The vent in "C" does not look adequate to do much, and it may be in the wrong location. You may want to experiment with throttling down all the radiator valves to provide more steam for the addition.

    Draw out a plan of the system, and label each radiator with its EDR, and the pipe sizes which supply the individual radiators, and also the main supply for that group. Somewhere here is a table of how much a given pipe size can supply, in EDR. When the addition was done, it may not have had a large enough supply pie for that group.

    Are there traps on the radiators, and if so are they functioning? One faulty trap could close its neighboring traps early, causing a cold zone.

    Is the thermostat set or adjusted for steam?

    Some traps and vents will not function properly when the pressure exceeds 3psi. Check that the pressuretrol is preventing the pressure from exceeding that.

    Pictures of the rads, traps and main vents are always helpful.--NBC
  • Jamie Hall
    Jamie Hall Member Posts: 23,650
    A couple of additional thoughts

    in addition to what NBC has noted.

    First, is there any vent at all at the end of main C in the addition?

    Second, check the pitch of everything.

    Third, is the boiler big enough?  As NBC noted, you need to add up the EDR of all the radiation on the system, and compare it to the required pipe sizes as they go along (the tables to which he refers are in The Lost Art of Steam Heating) and then to the rated EDR of the boiler.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Steamhead
    Steamhead Member Posts: 17,008
    You need a Steam Man to look at this

    the closest one to you that I know of is the Steam Whisperer, in Chicago. Not sure if he will come that far but it can't hurt to ask, since he's one of the best. Get his info on the Find a Contractor page of this site. 
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service