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Hello all I have a  3 year old Dunkirk steam boiler. Its a one pipe system with radiator vents. Its for an 8 unit building. 30 radiators total.

Heat is uneven.  One side of the building is 71 and the other is 67.

I noticed there are 2 Honeywell pressuretrols on the boiler. They are above the valves where you drain the dirty water. 1 on each side.  These pressuretrols are set at 5. Not .5 but 5. Is this good?

I also noticed the old main vents 3 of em:

2 have old Dole #4's. and theres 1 Gorton #1

I have been messing around with the gorton radiator valves and it has helped some but its still uneven and some radiators are hissing a little loud.

Any advice to getting this thing running like a champ instead of an amteur!?

Thanks in advance!


  • Rod
    Rod Posts: 2,067
    Main Venting and 2 PSI Pressure

    Hi- It would really benefit you to have a good steam pro look over your system. You might want to look in the "Find a Contractor" section at the top of this page. There are some really good steam men listed there.

    Before adjusting your radiator venting, you need to get your steam mains properly vented properly  and the operating pressure below 2 PSI. You didn't mention how many mains you have and which mains the vents were on.  Generally I'd say you are way under vented on your main vents at the present moment.  I would have a least a Gorton #2 at the end of each main.

    As an apartment you are normally required by code to have two pressuretrols . One runs the boiler and the other acts as a high limit switch . Rather than the setting on the pressuretrol you should go by what the pressure gauge indicates. You may want to get a 0-3 PSI gauge as this is easier to read than the 0-30 PSI gauge that is provided with the boiler. (Leave the 0-30 PSI gauge in place as it is required by insurance /code regs,)  The max operating pressure on your system should be more than 2 PSI.

    I don't know what sort of thermostat system you are using now but in your situation I would seriously look into something like a Tekmar 279, as properly setup, it can achieve better comfort and fuel savings.

    - Rod
  • Jamie Hall
    Jamie Hall Member Posts: 23,415
    More on pressure and venting

    There is just no way that the main vents you have are adequate.  The objective of the exercise -- particularly with one pipe in an apartment building -- is to get steam to the ends of the mains as quickly as may be, so that all the radiators start to heat at more or less the same time.  You just can't do that with the radiator vents -- you have to have adequate main venting.

    As Rod notes, as an apartment building you have to have two pressuretrols, or a pressuretrol and a vapoustat.  One of the pressuretrols, or the vapourstat, control the actual operating pressure of the boiler -- and that should definetly not be over 2 psi, and probably around 1.5 psi.  Higher pressures won't help anything -- and may destroy your vents in the process.  The other pressuretrol (or the only one, if you have a vapourstat) is typically set to cut out at 5 psi, and is there as a safety precaution in the event the actual controlling one goes west for some reason.  Some codes require this one to be a manual reset type, and I regard this as just good practice.  They should be on separate pigtails, so that if a pigtail clogs it doesn't knock both of them out at once.  You also have to have a 30 psi pressure gauge (actually, most codes say that the you must have a gauge which reads to twice the rated pressure of the pressure relief valve -- which is typically 15 psi).  As Rod notes, again, adding a 0 to 3 psi gauge isn't a bad idea.

    Once you get the main venting under control, then you can start playing with the radiator vents.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    A good low pressure gauge

    If you are paying for the fuel to heat the apartments, you need a 0-3 psi gauge to see what is going on with the system.

    If you want to spend less money on fuel, more main venting is needed. Why pay the fuel company extra to force the air out, when with generous main venting, it will leave with no effort.

    If you want to save even more on fuel, get a vaporstat, a good thermostatic control, and a combustion test on the burner.--NBC
    BEERRUNNER Member Posts: 4
    Main vents

    Thanks guys for responding.... I have 3 main vents.

    2 Dole #4's and 1 Gorton #1

    So should I replace them all?  with what vents?

    How hard is it to change a vent???
  • Jamie Hall
    Jamie Hall Member Posts: 23,415

    but without knowing the length and size of the mains, one can't really properly size the vents.  However, a Gorton #2 on each main would be a good place to begin.

    How hard it is to replace them is a little hard to say, too -- if you are really fortunate, the existing vents will unscrew from the nipples they are sitting on without too much fuss and feathers.  Or the nipples will unscrew from the mains.  For starters, then, you can install the new vents onto new nipples.  A word of caution.  Make sure the boiler is OFF and has been off for some time -- cold -- before you start wrencing on things.  Live steam burns really badly.  Another word of caution -- don't wrench on the vent bodies; they all have some place further down to wrench on.  And a third caution -- they have to be installed upright.

    Make sure your pressure is correct -- no more than 2 psi cutout -- or you run a real risk of destroying the new vents... which is discouraging.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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