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noob questions with steam

Hey guys, my girlfriend just bought a 1930s house with a 1 pipe steam system and I've been doing a lot of reading and now have a pretty good understanding of how things work, but still have some questions.  My first concern is the pressure gauge on the boiler.  From what I've read most steam systems run on around 2psi, but the gauge on the boiler reads about 13 when its cold and around 15-16 when firing.  The pressuretrol cut in is set as low as can be at 0.5.  Could it be that the gauge is just not calibrated?  Should a proper gauge read 0 when the boiler is cold?  I have attached a picture of the boiler.

Another question is about insulating the mains.  The main lines were not insulated at all when she moved in, it looks like they were previously insulated with asbestos and when that was removed they never put anything there.  So we bought a bunch of 1" fiberglass pipe insulation and did the basement aside from the elbows.  Will the elbows not being insulation make that big of a difference?  Also how close to the boiler shoudl we go with the insulation?  We stopped about 5 feet from the boiler.

The other question i have is about venting.  Pretty much all of the vents were releasing steam so we have replaced most of them and there are a few more that need replacing.  Now however, the radiator in the bedroom makes the room extremely hot compared to the others.  There was a jacobus #C I believe that was originally on it that was replaced with a #6.  It seems that the vents that were on the existing radiators differ completely from the chart I've been going by on maid-o-mists website, so I've been replacing them with the ones they recommend.  Maybe a bad idea?  That particular radiator also makes a very high pitched whistle noise with the new vent.  One other thing I noticed is that there is a radiator in the attic that the previous owner had the valve shut off to it.  Will this affect things?  We don't really need heat in the attic so having it on or off is not really a concern.

The last thing is there is a hot water loop coming off of the boiler to go to kickspace heaters in the kitchen.  These were not working and are do to be replaced shortly.  Will they affect anything as far as the radiators go?  I have attached some pictures of the boiler and the piping.  the ignitor on the boiler had to be repaired so that's why it is apart in the first pic.


  • MDNLansingMDNLansing Member Posts: 297
    Not a steam pro...

    but I think I can help with some of your questions.

    Looks like the gauge was damaged by steam. The gauge should have a copper pigtail (like the one one your pressuretrol) on it. I doubt it's one that can be calibrated so you'll have to replace it. When you do, put a pigtail on that side as well to prevent the new one from going bad too soon. If you are running from 13 to 16 you are in the ballpark of 3 psi in the system. The lower the better but you can;t trust that gauge completely if its broken. PSI might be a little high but it's hard to say. New gauge will tell you that.

    The more you can insulate the better. Even if it's just fiberglass wrap on the fittings it's better than nothing. If the fittings get cold in winter from drafts in the basement, the steam will in fact cool some and condensate. Wrap it with whatever you can, obviously the fitted insulation being the best but anything will help. Some people insulate all the way to the boiler, others stop short. 5' should be OK though as you won't get much cooling right at the boiler.

    As for the venting. General rule of thumb is to vent the mains as fast as possible and the radiators slow but completely. If the mains don't have any vents you might want to look into having some installed. If you feel comfortable drilling and tapping a cast iron fitting you can do it yourself, otherwise a pipe fitter / plumber will be needed. On 80 year old pipes you might be rolling the dice on that one doing it yourself. It just depends on how handy and experienced with tapping you are. If you do break the fitting it might be a real pain to replace it. DIY'er beware. Venting on the radiators also needs to be consistent. You might need to swap and move vents around to balance it right. You want them all to vent at the same rate and time, but some will need to vent more air than others. Balancing is an art, I'm convinced of that. It's something the steam pros are so good at, they can look and tell you what vent is needed. You can get it yourself though, just consider moving them around and finding the right combination.

    Ideally, your steam to hit all the radiator valves at the same time, then all the radiators to vent themselves empty of air at the same time. Think about how far a rad is from the main. The further away, the more air to expel. Those radiators need larger vents. Shorter take offs from the main and smaller rads have less air, thus can use smaller vents.

    As for the attic, it depends. I found out in my house that the take off that feeds the third floor also feeds a few second floor radiators. I have a 2 pipe system so closing off the third floor prevented the steam from quickly reaching the second floor since it wasn't venting through the third floor radiator. So I leave mine open even though its unused space. This allows the take off to vent properly and the steam to reach the second floor properly. If you close them and the other radiators still get steam, I'd think you could leave them closed.

    Hope this helps. Keep asking the questions and the pros will help you have the system running tight in no time. The help from the pros on this site really is amazing.
  • cicatriz63cicatriz63 Member Posts: 10

    Thanks for the reply and alot of good info.  The mains are indeed vented.  There are 2 mains coming off of the boiler and there is a jacobus #1 on the end of each that were just recently replaced as the old ones were spewing steam like a sieve.  The main problem we are having now is certain vents making a ton of noise, particularly the one in the bedroom that we just replaced.  The hissing sound is bearable but the high pitched whistling is driving us nuts, and it seems like the boiler could be short cycling as the noise happens about every 20 minutes or so.  From what I've read a whistling vent means to replaced it.  What does it mean if it is already replaced?
  • cicatriz63cicatriz63 Member Posts: 10

    Does anyone have any ideas about the whistling vents?  It's driving us nuts!  It sounds like it is happening after the heating cycle is over and the air is presumably returning into the vent.  When the heat kicks on and the air is being pushed out they sound normal.  Then after a while they start making this high pitched whine.  All of the vents were recently replaced.
  • MDNLansingMDNLansing Member Posts: 297
    New Vents

    Try changing the model of vent and see it that helps. Certain vents will sound differently when the system is cooling and creating vacuum. It might just be your particular model. Start with just one and see if it's better.
  • Whistling vents

    That is caused by your main vents, being still not adequate, and also unable to relieve the vacuum which develops at the end of the cycle.

    Don't just replace your old gauge with the same sort, get 2, one 0-30 psi (for code), and another 0-3 psi (for diagnosis). Add main vents (Gorton 2's), until the back-pressure of venting at the beginning of the cycle is a couple of ounces. Try to adjust your pressuretrol to cut out as low a pressure as possible (absolutely no more than 1.5 psi).

    Hold off on all that insulation until you can be sure all the supply pipes are pitched properly, and you may still have to repipe your header to produce dry steam.--NBC
  • cicatriz63cicatriz63 Member Posts: 10

    Thanks for the replies.  Bigger main vents were my initial thought so we will grab a Gorton #2 and see if it makes a difference.  We already insulated the mains except for the area immediately around the boiler.  She has an even bigger problem now as the boiler has an electronic pilot which is no longer working properly, so sometimes the boiler just does not turn on.  She had a heating company look at it and said it would cost about $1500 to fix.  The boiler is 30 years old so at that point she's considering a new boiler.  Is anyone familiar with these types of pilots?  From the looks of it when the heat kicks on there is an electronic ignitor that lights the pilot which then lights the boiler.  The problem is the pilot never lights and we can hear the ignitor clicking trying to light.  Sometimes it lights but other times it won't and the boiler just won't light.  The pilot can manually be lit to at least get it working but I don't feel good about it at the moment.
  • MDNLansingMDNLansing Member Posts: 297

    Can you manually light the pilot while the ignition is firing? Try lighting it with a long lighter while the ignition is clicking. If it won't light. you might need to replace the gas valve. If it does light, it might just be bad ignition spark.
  • cicatriz63cicatriz63 Member Posts: 10

    Yes, if the ignitor is clicking we are able to manually light it and the boil will fire up normally after a little bit.  It appears that it is just a bad ignition spark I'm not sure why the guy said it would be so much to replace.  I'm guessing because of how old it is.
  • mcsteamymcsteamy Member Posts: 77
    edited November 2013

    I have no idea what the price ought to be, but remember -- three quotes for everything.  Replacing this is something any competent heating company ought to be able to handle, even if not steam proficient.

    As for the whistling, at what pressure is the boiler cutting out now?  You want that Pressuretrol cranked down so low that you can't crank it down any farther, with differential set at a pound.  Set the anticipator on the thermostat as long as it will go, or if digital, as few cycles per hour as possible.

    Also, the proper way to disable a radiator is to plug the vent hole or, with most vents, turn the vent upside down.  Don't close the valve.  It may leak steam and fill the radiator with water.
  • MDNLansingMDNLansing Member Posts: 297
    No Pricing

    Price discussions are prohibited on the boards, but it shouldn't cost much to do this job. Agreed, get some more quotes. This job shouldn't be an eye shocker.
  • cicatriz63cicatriz63 Member Posts: 10

    The slider on the front of the pressuretrol is set as far down as it can go.   As far as I can tell that is the only setting.   Am I missing something? Not sure what the differential or the anticipator.   Guess I have some more reading to do.
  • mcsteamymcsteamy Member Posts: 77

    The differential is probably on a thumbwheel inside the Pressuretrol.  Set it down to a pound, if it isn't already.  Does it say on the box whether the Pressuretrol is CUT IN or CUT OUT?

    Anticipator is what was used on analog thermostats to determine the time between firing cycles.  With steam you want it set long so that you don't get short run-times.  You want the boiler to run long, and infrequently on temperature, and as necessary on  pressure in order to reach the set temperature.  Basically, once the pipes are hot, we want to keep them hot, but not by running the pressure high.  Make sense? 
  • cicatriz63cicatriz63 Member Posts: 10
    edited November 2013

    Ah that makes sense now.  The front of the pressuretrol says Cut IN and it is set as far down as it will go.  There's nothing else on the front but it does look like theres screws to open it up so I will try taking the cover off and see.  I also looked at the thermostat and found the anticipator and it was set for almost as short as possible.  Should it be all the way to the longest setting?  Reading some things online says to gradually move it until it is the right balance.
  • mcsteamymcsteamy Member Posts: 77

    With a CUT IN the Presstrol will turn the boiler back on when pressure gets drops back down to the pressure on the front after it has hit the pressure on the front plus the differential and shut off.   It's probably already set at one pound, but you don't know until you check.

    If you have a standard round Honeywell thermostat, if I recall you move the lever on the bottom under the faceplate to the left.  I have mine almost as far over as it will go.  You will get more temperature swing in the house, but should also get lower heat bills.  The idea, of course, is that once that boiler is making steam, and everything is hot, you want to use that heat UPSTAIRS to fill up the radiators, and not on constantly heating up pipes and equipment in the basement, where it just goes out the walls unused by you.  So if the stat lets the temp drop 2 degrees instead of half a degree between cycles, you will put more of your fuel toward getting heat where you want it.  Note:  Once you have the pressure down, the boiler might SEEM like it is short-cycling if and when it bounces off the Pressuretrol.  This is perfectly fine UNLESS it does it very quickly on a cold firing cycle.

    It's pretty basic stuff, but these few simple problems account for most of the issues people have with steam.  You're already on the right track with the vents.  Good luck!
  • cicatriz63cicatriz63 Member Posts: 10

    So I opened up the pressuretrol and the little wheel was just over 2 so I turned it down to 1.  The boiler is definitly turning on and off more frequently now, this is normal behavior then?  I'm not exactly sure how long it would run before but now it seems it only kicks on for a minute or 2 and then shuts off for about 5 minutes or so.  It's normal to be this frequent while maintaining room temp?  The vent is still whistling like crazy.  At this point we might just try a different vent and see if that makes a difference.  We're also getting a bit of water hammer only once in a while you will hear a pipe bang.  All of the radiators are properly pitched is there anything else we can look at?
  • BobCBobC Member Posts: 4,406
    Boiler to big?

    Your boiler is probably to big for the system it is driving, that means it builds steam faster than the radiators can condense it so pressure starts to build. Now that you have lowered the operating pressure the boiler is reaching the setpoint earlier than it did when the pressuretol was set higher. The lower pressure setting will save fuel so you are ahead of the game.

    How long are the steam mains in the basement? .If they are longer than 15 ft of 2" pie you might need more venting on the mains. You could just add another #1 to the exiting ones.

    While your down there looking around use a level and make sure the pitch

    on all the piping is correct, use a piece of string on long runs to

    check for any dips in a pipe run. Water hammer is caused by steam collapsing when it comes across standing water, you have to find out where that standing water is. Also make sure all your radiators have a slight pitch towards the input pipe and make sure all radiator valves are fully open so water can exit the radiators easily.

    Next make a list of your radiators and list the size (height, number of columns deep, number of columns wide), the vent on each one, the length of the run-out from the main and what floor it's on. This list will let you figure othe EDR of your radiators and then make sure the venting rates are right. If you vent a radiator too fast you create a lot of condensate and you can end up with uneven heat and sometimes make hammering worse.

    My old boiler was three times to big for my system but by running at low pressure and venting the mains fast and the radiators slowly I had a system that heated economically, evenly and quietly but it did short cycle because it was just to big.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • cicatriz63cicatriz63 Member Posts: 10
    edited November 2013

    The boiler is definitely oversized, I'm not sure by how much though.  I will have to get the specs and measure the radiators to get the EDR.  The mains are definitly longer than 15 feet, probably closer to 30.  I think we are going to try putting the Gorton #2s on and see if that makes a difference. As far as the pitch goes, they should be sloping down in the direction of the steam correct?  Towards the return line?  Just eyeballing they do look like they are sloped a bit, I'll double check with the level though.  I appreciate all the advice.  Learning of lot of good info on this site.

    Edit I just measured the mains and 1 is about 45 feet and the other is about 40, so we will definitely order some Gorton #2s and see if that helps.
  • BobCBobC Member Posts: 4,406
    More venting

    A 40 ft 2" main has about 0.87 cu ft of air in it; if it's a 2-1/2" main it has 1.36 cu ft of air. It sounds like you really do need more venting.

    The mains should gently slope towards the boiler return in a parallel flow system; if it were  a counterflow system the main would slope back towards the steam supply. Sometimes your eye can be fooled so it's best to use a level and stretch a line along the main and any long radiator runouts to be sure you don't have a sag that will pool water..

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • cicatriz63cicatriz63 Member Posts: 10

    Sorry I forgot to specify, they are 2" mains.  I'll order the #2s and see if they help.
  • SteveSteve Member Posts: 234

    You may be able to have the boiler downfired to reduce output. Ask a pro if this is possible.
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