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What if over the years things were removed?

GaryG Member Posts: 6
I just bought a 2000 sq foot house with steam. It appears that over time and renovations that there were some 4-6 radiators and associated piping removed. The boiler is huge(7 feet long by 3 wide and 5 tall) for a house. I have the pressuretrol as low as it goes and am still getting hissing spitting vents that dont close. Could the boiler being oversized be causing the pressure in the system to be going to high? Would changing to a smaller oil burner nozzle help? its a 1.25 gallon 90degree hollow nozzle now.  Please help, we are using 100 gallons of oil every 2-3 weeks and its not even cold yet!


  • thirsty basement monster

    what type of system do you have-1-pipe. 2-pipe?

    you won't know if the pressure is too high, without a good low pressure gauge [gaugestore.com 0-3 psi]. probably the pressure will be too high without a vaporstat [0-16 oz.]

    check your mainline, not radiator venting as well, as you may be burning extra fuel in order to force the air out. these systems work best on ounces of pressure, while high pressure makes extra work for the oil company. the steam can only move up to the radiators, when the air is let out; and there is a lot of air in your boiler, and pipes.

    the boiler may now be over-sized, but perhaps could be down-fired by a competent pro.--nbc
  • lastly but not leastly

    check your thermostat for location [free from draughts], anticipation, and "steam-rated" [if digital].--nbc
  • Jamie Hall
    Jamie Hall Member Posts: 19,966
    Some of those old boilers

    you could just about move into, with room left over for the cat.

    It probably is oversized.  However, it may be very difficult to down fire it enough -- if at all; at some point you may want to put in a new boiler more closely sized to your existing radiation -- it's one of the changes that probably will save you money.  You might also consider the possibility of changing to a different oil burner completely, even without changing the boiler -- you may have an older burner which is itself less efficient than the newer flame retention ones.

    When and if you do change the boiler, be careful to match the water lines, new to old.

    The boiler being oversized, however, will not in itself cause the pressure to go too high -- if in fact it is (sounds like you are trying, at least!).  What will cause it is an old pressuretrol which is either set too high or which can't be set low enough.  As NBC noted, the only way to be really sure that your pressures are low enough is to add a low pressure gauge -- you can put it on the same pigtail as the pressuretrol -- and see what you get.  Ideally you should not be going over 1 1/2 psi, but the pressuretrol you have may not do that.

    What will save you oil, though, in this situation is a new boiler... and I can't guarantee it, but I'd be surprised if it didn't save enough oil to pay for itself over only a few years.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • David Nadle
    David Nadle Member Posts: 624
    Check the pigtail

    Nobody's mentioned it yet, but on an old boiler there's a good chance the pigtail is plugged up and the pressuretrol is never seeing any pressure.

    Personally I recommend having a brand new red brass pigtail in hand before removing the old one. Just in case.
  • good point!

    pigtails can get very plugged, and if the pressuretrol is the mercury type, mounted on a wrong orientation pigtail, pressures can be very inaccurate.

    one thing to note on these old boilers is the enormous volume of the steam chest which must be vented along with the mains before any steam will rise. this could translate into an extra gorton #2 just for that. noisy radiator vents are a sure sign that more venting is needed, either to let the air out, or for vacuum relief. don't vent with your wallet-buy more vents!--nbc
  • GaryG
    GaryG Member Posts: 6
    learning, doing and more learning.

    One pipe system.

    Installed a 5 psi guage near the pressuretrol, 3 new main vents, lowered the pressuretrol setting as low as it can go and then installed new radiator vents after checking that the boiler was being shut down by the pressuretrol.

    The pressuretrol doesnt shut the boiler down until the guage is just over 2psi and then the boiler kicks on again when it gets just below 1.5 psi. I have eliminated any and all spitting and hissing of vents, but realize that i probably still have too much pressure.


    1. From cold start until pressuretrol cut out is approx 45 min.

    2. It only takes about 2 minutes for the steam pressure to drop from cut out pressure back down to cut in pressure. (1psi - as low as it goes)

    3. I drained the system and the water was filthy dark brown all the way till empty.

    Any other suggestions are welcome and hoped for! 

    One last question: I have readsome places that the burner flame should be blue and in others that it should be yellow, what is correct?
  • Jamie Hall
    Jamie Hall Member Posts: 19,966
    Good show!

    You're making headway here!  Wonderful what lowering the pressure can do; it's a shame you can't get it a little lower, but it is quite possible that your pressuretrol just won't do it.  Let it be for the moment.

    The dirty water wasn't helping any, I'm sure, but it's not too surprising if the system hasn't been blown down from time to time.  Opinions on that differ -- but taking a few gallons off every couple of weeks seems about right.  If you have a low water cut off (and you should!!), that is the place to drain.  My procedured -- and there are others -- is to drain a few gallons until it seems clear, close the valve and refill (unless you have an autofill, which takes care of that), then open the valve again and drain some more -- and repeat, until when you open the valve the water is at least moderately clear.  You won't want to drink it, but at least you shouldn't be able to walk on it any more.

    If you have questions about the operation of the burner, though, you should have it adjusted by a professional burner tech., with the right tools.  Playing with burners is not recommended unless you really do have the necessary equipment and training.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • jim_72
    jim_72 Member Posts: 77

    Gary ,Jamies post was spot on.Pressuretrol appears to be kaput. One good thing ,assuming your oversized,  is 2 minutes to drop 8oz of pressure from cut out to cut in is decent. If you replace the pressuretrol you will be able to get decent cycle lengths from 8oz cutin to 24oz cutout. If there is no new boiler in your close future getting a Pro to check the burner for efficency  will reap benefits.Since the boiler is old and quite large it may be safe to assume that there is a build up of sediment on the bottom that will require more then a single draining but a power flushing.
  • mchema
    mchema Member Posts: 37
    Having kind of the same issue

    Moved into our home and this is the first season with steam heat. We noticed something was wrong when we where hearing what I called the "Tea Kettle Squeal". Steam vents would just open up half way through the cycle and squeal like heck... Finally found someone who knew what the heck they were doing and let them have a go at the system....

    Although my Honeywell pressuretrol is set correct, we checked the pressure and let's just say it is too high... We didn't have enough time to address this issue because we increased our main venting capacity and worked on a couple other issues. But when he comes back he will be cleaning the pig tail and making sure the pressuretrol is working. Also he will  adjusting the firing rate of the burner... As we discovered our boiler most likely is much too large... My wish for xmas would be a quiet running, not high pressure system... :p 
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