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

Slow to heat all radiators - Trying to figure out venting.

Hello Good Folks:

I’m new to learning about steam, mostly from this amazing website!

I recently had a Burnham IN4 steam boiler installed. From a cold start (water in boiler at room temperature) it takes approximately a 35-40 minute call for heat for all my radiators to get good and hot. I’ve got a small house, 600 SQFT x 2 floors = 1,200 SQFT + basement. I’ve got 4 radiators on each floor (1st and 2nd for a total of 8) + a hot water baseboard loop in the 1st floor living room.

2 radiators off a branch at the begging of the main are quick to heat up, the ones furthest away on the 2nd floor are slower. I’ve got Vent-Rite adjustable vents on all the radiators and I’ve been somewhat successful at tuning the vents to balance the radiators out.

The main only has 1 vent (Vent-Rite #35). It's at the the end of the main at a T above the wet return (See Photo). From what I’ve read that vent is not enough venting. Also, ideally the vent should be back a bit from the end of a main but there are obstructions (support beam, wall, drop ceiling on other side of the wall etc) so I can see why perhaps it is where it is.

I took the Vent-Rite #35 off and ran a timing test to see how long it takes to get steam at the end of the main, HOWEVER before steam came from that direction, steam was coming UP from the wet return so I shut it down and put the vent back on.

Should I just get the largest size replacement vent available with a 3/4” male tread? With a larger size vent on, will steam come UP from the wet return (is that normal?) and cause a problem?

Any thoughts are much appreciated!


  • jhewings
    jhewings Member Posts: 139
    More pictures of the boiler and piping from different angles would be helpful.
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    Time from cold start is not too helpful here.

    Here are times to share. All times should come just after steaming so we aren’t timing the wrong thing. Stop the boiler mid-cycle, let the air return to the system for 5 minutes then start it again to get these:

    - time from steam start to steam at main vent
    - time from steam at main vent to steam at typical “fast” radiator
    - time from steam at main vent to steam at “slow” radiator
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    Youve hit the obvious -- that VentRite as a main vent is too small.

    However -- if there is steam coming up from the wet return, there's a real piping, or possibly water level, problem somewhere. As @jhewings said, more pictures, particularly around the back of the boiler...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • neilc
    neilc Member Posts: 2,703
    we need to see how that wet return connects back to the boiler return
    known to beat dead horses
  • dopey27177
    dopey27177 Member Posts: 887
    What is the circulating pump for?

  • jhewings
    jhewings Member Posts: 139
    edited February 2022
    Is it possible you are mistaken the steam is coming up from the wet return? That would be very unusual. The water that should be in the wet return would block steam. That "p-trap" at the bottom of the pipe that drops to the wet return is unusual. It would act like a dirt trap for red muck. A tee there would be better and allow you to clean out the wet return.
  • jhewings
    jhewings Member Posts: 139
    edited February 2022
    Although the location of the main vent is not ideal, there are many done like that. You seem to have a lot of space above the tee, so you could put a Gorton 2 or a big mouth as high as possible above the tee.
  • mattmia2
    mattmia2 Member Posts: 9,632

    What is the circulating pump for?


    And is it dropping the level in the return when it is on.
  • veteransteamhvac
    veteransteamhvac Member Posts: 73

    What is the circulating pump for?


    Doesn't he mention he has a hot water baseboard loop? I presume that's what that is for.