Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Attic room radiator issues

Hi all, I am in Queens NYC and just had a new WM PEG-45 boiler put in last Saturday. I have convector style radiators throughout the house. (this is not the problem)

The pre-existing problem:
See attached set up.

The room: The room was converted from attic to a ~125 sqft bedroom in a cape style house. (before I bought the house) I recently had it re-insulated to code because I am just frustrated of it being cold all the time.

The problem radiator 2C: its the longest radiator in the house at close to about 5 feet or so and it doesn't warm up as fast as I would like it to. It's on a really long branch because its the last radiator on 2nd floor to warm up. I have a Maid-o-mist #D sitting on it for now. I have tried using Verivalve as fully opened but have not had any successful results.

- The new boiler is set cut in and out at a higher pressures. I believe its at 1.5 - 2.5. (can confirm later on as I am at work right now)
- The first radiator (2A) on the 2nd floor is now hissing. I am guessing this is due to the higher pressure from the boiler as it is the first one in line.

My next steps:
1. Reduce the pressure?
2. Replace the Hoffman 41 on the fist radiator 2A to a Gorton #4?
3. Replace the Maid-o-mist #D to Varivalve again?

Let me know what you folks think I should do...

P.S. 1st floor warms up super nice without any issues. (When I got my basement redone, i didnt find any Main vents on the 1st floor main. :open_mouth: )


  • Gary Smith
    Gary Smith Member Posts: 367
    Do your steam mains have main vents? (very important to balancing).
    Are your steam mains and near boiler piping insulated? (balancing is easier if they are).
    Turn down the pressure at the pressure trol. If it is additive 0.5 on the main indicator and inside dial set so the "1" is toward the front of the house.
    Do not use vari-vents they will make balancing nearly impossible.
    See what happens after you do the above (or at least turn down the pressure).
  • brandonf
    brandonf Member Posts: 188
    I'm no expert. But depending on thermostat location and main venting the boiler could be shutting down before any steam makes it to the last rad. It wouldn't hurt to find out whether the boiler is kicking off on temp or pressure. Just my thoughts FWIW.
    Homeowner, Entrepreneur, Mechanic, Electrician,

    "The toes you step on today are connected to the butt you'll have to kiss tomorrow". ---Vincent "Buddy" Cianci
  • Jamie Hall
    Jamie Hall Member Posts: 17,103
    Odd... there is another thread on here about whether or not to put a vent on a runout, and I said that -- in general -- probably not.

    But... to every rule there is an exception. If, after you have put main vents on and balanced things as well as you can without it, you can try putting a vent -- probably a Gorton #1 -- on the runout and riser to that problem radiator before the radiator valve. May require some creative plumbing...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 10,328
    Your 2d floor main has no return. Is this a counter flow main?? Counterflow is lower at the boiler and higher at the far end.

    If it is a counter flow it needs a drip installed. I would also install a riser vent on the supply to the the attic radiator before it enters the radiator and a vent at the end of your first floor main
  • BobC
    BobC Member Posts: 5,230
    I agree with everything above but make sure the runout to that last convector does not have a dip in it that might be holding water. Usually that might cause water hammer but can also condense steam before it gets to the convector.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge