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Radiator air vent observations

Dave in QCA
Dave in QCA Member Posts: 1,786
I thought I would post this and see if anyone else has made the same observations.

In assisting a friend down the street who had a new boiler installed a few years prior, and it never worked correctly, I found that some radiators were venting way too fast, and the mains to slow.

First, I improved the main venting.

I noted that the installer had replaced most the the Hoffman #40 vents with Hoffman 1A vents, and had not bothered to attempt to balance them. 


Problem, when the boiler fired, the nearest radiators got hot quickly, the end of the line, in the dining room, where the thermostat was located was last to heat, CORRECTON....., even with its vent completely open, it would not heat until the boiler had been running about and hour, and the rest of the house was overheating.

Then I began to close down the 1A vents on the nearest radiators without much improvement.  I closed them further, then further.  Some radiators seemed to slow down, others did not.  I completely removed the adjusting wheel and noticed that the way these vents are manufactured, there is a great deal of play, and therefore, even though the wheel may be turned to the 1 position, it may be venting as fast as 5, for example.  The side to side slop can make more difference than an adjustment of 1 to 5, for example.   I very carefully took the tops off of each 1A and adjusted it to a position 1.5 and made sure that the adjusting ring was centered.  When all of the vents were adjusted, the system came into perfect balance - all radiators heating at the same time!

Later, I compared the Hoffman 1A to some older Dole 1A vents that I had at my building.  I notice that the old Dole 1A vents have no play in the mechanism at all, and produce very good results by the adjustment.

I understand that Dole was sold out to another company and that the quality has greatly suffered, so I understand that the Dole 1A may not be a reliable alternative.

My observations lead me to conclude that the best method of balancing is by using the tables and formulas that are available through this site, and using nothing but Gorton air vents to balance this system out.

My other inclination, is when most of the radiators are nearly the same size, to used the old reliable, Hoffman #40.  I know they are slow, but as BoilerPro keeps preaching to us, "Vent your mains fast, and your radiators SLOW, but completely."   My observations are that "SLOW" for the radiators is as critical as "FAST" is for the mains.

Back to my main reason for posting this, I have been wondering if others have had unsatisfactory experience with the Hoffman 1A because of the sloppy wheel adjustment.

Dave in Quad Cities, America
Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.


  • Gordo
    Gordo Member Posts: 857
    edited June 2011
    Hoffman 1A Vents

    Yes, I would totally agree with your observations regarding the non-reproducibility of the Hoffman 1A vent settings.  

    They are generally not worth the extra you pay for them.

    We have found that the Vent-Rite 1A is a better product for the money, with the added bonus that the vent at it's lowest setting shuts the radiator off - most of the time.

    We had one case where a Co-op was running their boiler at 7.5 psi (we had no control over that, unfortunately!) and we installed a Vent-Rite to control the overheating.

    I am pleased to report that only  two of ten sections heated up, even at those extreme pressures. 

    The Hoffman 40 which we replaced allowed the entire radiator to heat within minutes.

    The Vent-Rite is not the best choice if you need more venting, however.  At the highest settings, it tends to hiss and whine and fail in the open position. 
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • crash2009
    crash2009 Member Posts: 1,484
    I don't care for the Hoffman 1A either

      Like you, I thought the adjustment was sloppy.  I never bothered to dissect it to find out why.  But thanks for that, maybe I will give them another chance sometime in the future.  I have heard rumor that the Hoffman is not recomended to be used in the bedroom due to the distinct "pop when it closes".

    I have had good success with the Ventrite 1A.  I use the Ventrite in the problem areas of my system.  One is on a small convector which is 5 feet from the thermostat.  And the other two are coralling a couple steam hogs.  I have tried Gorton 4's and 5's on the hogs, but the Ventrite seems to force them to share the steam.    

    I use Gortons everywhere else.
  • gerry gill
    gerry gill Member Posts: 3,078
    i would agree

    with your observation.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.

This discussion has been closed.