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Paul system conversion, sub manifold question

Luv'nsteam
Luv'nsteam Member Posts: 272
The way my one-pipe steam system is laid out, basically I have 7 radiators near the front of my home and another 6 near the rear of my home.  And there is about 50 feet between the two areas.  So, in my layout plans for vacuum lines, I was thinking to make the installation easier, of using two manifolds: a main manifold, near the front of the house, boiler and vacuum pump and a second manifold at the rear of my home, at the end of the rearward steam main and to have a single vacuum line attaching them both together.  This will save me a few hundred feet of vacuum line and quite a hassle on the installation too.  Do you see any issues with running the lines this way and having two manifolds?



Also, when I build the manifolds, I was thinking of using a check valve at each port for each radiator.  My thoughts on this are that if a leak appears anywhere from the radiator to the manifold, the rest of the system will not lose vacuum.  Your thoughts?



And another idea was to add an ac/r schrader valve at each port, between the check valve and line connection so I can check each individual vacuum line for service/trouble shooting.  Thoughts on this?



Any other ideas/thoughts anyone would like to share?



Thank you,

Mike

Comments

  • Rod
    Rod Posts: 2,067
    Paul Manifold Schematic

    Hi Mike-  I'm trying to get a visual idea of what you have in mind.  What are you going to use for main vents?  What size/type of tubing are you using to connect the Paul valves to the manifolds? Your proposed  manifold setup seems like a good idea.  Just for the heck of it  I sketched up a schematic just for thought.



         I would use plastic fittings as much as possible as you will find them generally much less expensive than metal and plastic will work fine for this application though you may want to pipe between the check valve and the pump using metal for at least for a foot or two away from the pump as pumps can get hot. The metal piping will give the heat a chance to dissipate before it reaches the Pvc. I’ve used Plastic and Pvc extensively for vacuum form setups where the temperature of the mold and parts were several hundred degrees so as long as there isn’t direct contact with heated metal (ie the pump) it should be fine.

           I don’t think you need check valves on each line however I would use a individual valve on manifold for each paul line so you could isolate the line or shut off other lines if you want to test a line individually using  the vacuum gauge that is mounted on each manifold.  The Schrader valves aren’t a bad idea though I’m not sure just quite how well they would work in a  vacuum setting and I tend to think that with less fittings, you will have less problems.

            On the diagram I put at PVC ball valve at the end of each manifold so you could isolate the manifolds from each other. The Vacuum Tank allows for a reservoir of vacuum and also will separate any water and prevent it  getting to the pump. The Dump Valve allows you to break the system vacuum if need  be.  The Check Valve helps take the strain off the pumps valves when the pump is shut off.



    I’ve used MC Master Carr  http://www.mcmaster.com/   a lot for parts. You’ll find Polypropylene Plug Valves on Page 440 of their catalog  and if you need them,  plastic check valves on Page 481.

    Home Depot can supply you with most of the PVC pipe and fittings you will need.

    The Gauge Store has vacuum gauges . This is the model we used for vacuum forming http://www.gaugestore.com/prodinfo.asp?number=38534

     

    Hope this is of help to you. As I mentioned, the schematic is just for ideas and I’m sure it can be greatly improved  on.  Let us know how your system works out as I know a lot of us are interested in the outcome.

    - Rod
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Great sketch, Rod!

    I wish my sketches were that neat!  I like it though, it helps visualize the build.  Also, sorry so long for the delayed response, time is something I have trouble finding.



    I am still looking into materials for the vacuum lines from the manifolds to each Paul valve.  It is one of a multitude of projects I am oh so slowly working on.  Your reply to another post of mine (armor for vacuum lines) has lead me into looking for a low cost thermo-plastic.  One of the materials has steam-handling characteristics, but is not flexible and the polypropylene does not seem able to handle the steam if they contact each other.  However, I am still looking and need to talk with some suppliers.  To answer your question, I am looking for 1/4" ID line for the vacuum lines.  For lines between the manifolds, I had not given it much thought, but small ID is what I was thinking.  My thought is the larger the diameter, the more vacuum or more run time of the pump will be needed to effectively evacuate the lines and radiators of air.  Do you agree?



    As for PVC, would CPVC be better at handling the potential heat or do you think it does not matter?



    Thanks again, Rod.

    Mike
  • Rod
    Rod Posts: 2,067
    Paul System

    Hi Mike -

    I think you’ll be okay with plastic and PVC lines as, at least in theory, the steam is stopped by the Paul Vent so by the time any hot air / bits of steam reaches the manifold it shouldn’t be that hot.  As I mentioned we have used PVC for vacuum lines on vacuum form machines which get quite hot (400 + degrees) and this hasn’t been a problem.  I thought that using plastic would be much more economical than using metal and you could change to metal if desired after you have worked the bugs out of your system.

    As to the sizing of the piping I guess that would depend on what type of flow you are expecting and what size vacuum pump you intend to use.

    According to Gerry Gill’s and Steve Pajek’s venting chart, a Hoffman #3 (Paul Vent) vents at between  0.175 to 0.416 cfm on 1 to 3 ounces of pressure.  Have you calculated the total amount of air in the system (boiler, mains, dry returns, individual radiators etc, )  and have you decided what vacuum capacity you will need from the vacuum pump? What are you going to do for main vents?

    - Rod
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Hi Rod,

    Plastic is definitely cheaper and if it works and I am not against it.  Mostly, I do like to build things with over-kill strength, but currently, cost is more of a consideration than in the past.  This too shall pass, I hope.



    Anyway, per a private email conversation I had with Dan about this, he suggested first using 1/4" PIX for the vacuum lines (I may still, I am undecided) and then a pump that would pull about 5" of vacuum.



    As for the vents, all of them, I do have Gerry Gills vacuum vent chart and I did crunch all of the numbers.  For the initial run and the first season after my new boiler is installed, I will have all normal vents on mains and rads.  I had intended on master-venting a tall riser, but have not the room for the tee and straight gate valve at the top radiator.  When I setup the system to behave like the Paul system, I will replace the main vents with appropriate Paul valves unless I learn of a better idea.



    I truly appreciate your input about the PVC handling the steam and high heat.  That is not something the PVC manufacture advertises.



    You may also want to know, my system will be a vapor system, running at 8oz of pressure.  Are there any other numbers I can provide to you?



    Thank you again,



    Mike
  • Rod
    Rod Posts: 2,067
    Vapor or Air Venting Assist?

    Hi Mike -

       I ‘m not saying that PVC will handle the heat,  just that the PVC is far enough away from the heat source and since the Paul lines primarily handle air and that has time to cool before reaching the PVC that I don’t think heat will be a problem.

       With the Paul system I’m not sure exactly quite what the ultimate object is. Are we trying to make a one pipe steam system into a quasi vapor system that runs at a lower temperature or are we trying to run it as a normal one pipe steam system and are just speeding  up the release of air from the radiators?   What you are trying to accomplish would determine the volume capability that you would need of the vacuum pump, and how you would handle Main Venting etc.

    - Rod
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Vapor + vacuum steam heat = the best!

    Hi Rod,

    Unless I am confused (entirely possible) a vapor system is defined by a very low operating pressure, ie: under one psi.  This is why I will be running my system at a whopping 8oz of pressure, max but with the ability to perform a 10psi blow-down to clean things out.



    As for the Paul conversion, well, let me back up a but first.  Per TLAOSH, Dan states (and I believe him) that "steam runs from high pressure to low pressure, always".  In a normal one-pipe setup, the rads, when cool and air vents open, are effectively at 0 psi (I know this is not correct, but for the sake of description, I am sticking with it).  When the boiler comes to steam, it will operate at my my maximum pressure of 8 oz psi, 8 oz above the 0 psi at the rads.  This means the steam will rush to all rads (I do not know how to do the math, but in TLAOSH, I sort of recall Dan saying the steam will move at about 30 mph?).  When the Paul vacuum system (or any vacuum) is used, the pressure at the rads and if plumbed for vacuum, the mains, also, will be less than 0 psi, causing an even great pressure difference between steam pressure in boiler and pressure at the rads.  This will translate to the steam arriving at each radiator even faster than when they are at room pressure.  Again, if my memory is holding......in the article I read about this somewhere on this awesome website, the efficiency was verified to be an increase of 30%.  That's huge!  This is why most steam folks are curious about the Paul conversion I am doing.  It saves oil and that translates to saving cash.  However, in order to know how much I have saved on fuel with the Paul system (better worded to ask "what is the efficiency increase, measured?"), I need to have at least one full season that is representative of a typical winter as a base line to compare against.  Does this make sense?



    As for the PVC, while I was not clear in text (my wife says not in my words either, but I digress) I did understand you meant the heat would likely not be an issue with the plastic so far from the radiators.



    Thank you,



    Mike
  • Mark N
    Mark N Member Posts: 1,090
    Savings

    I would think that the 30% savings were based upon a Paul system that ran on coal. With oil you have intermittent firing and I would think that the benefit of the Paul system would be better and more even distribution of the steam. How long does your boiler run on a call for heat? Do you think it will be 30% less when you are all hooked up? I have a 1-pipe steam system. I run at less than 1 ounce of steam pressure. Last heating season from Nov to April It only cost me a little over $800 to heat my house. I also keep it warm 70 degrees. Before I went crazy with Paul vents and air lines and a vacuum pump, I would look to see if there are other places to economize. Proper main vents, balanced rad venting. A 1-pipe system can be very economical and simple to operate. Is your boiler properly sized for your system. An over sized boiler wastes fuel every time it runs.



    Mark
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Hello Mark,

    You pose good questions.  About my boiler, the original was MASSIVE, twice the size needed, in fact.  It seems to have been installed in the late 1920's or early '30's.  My new boiler has been sized according to what I have read in TLAOSH and includes the four additional radiators I have added.



    As for economical upgrades in other areas - they are coming; new windows, doors, etc (I have already insulated).  The boiler needed to be replaced first, however, as it used 800 plus gallons of fuel and it also tended to leak periodically.  I have also replaced the condensate return lines and added four new take-offs for the additional rads (one in the attic, and boy, that was a bugger for the four of us to carry up!).



    You may be correct about the Paul vacuum system being better for coal-fired boilers, but the theory is still sound.  My only caveat is, I must use an electric vacuum pump to produce the vacuum.  I will be looking for a steam injector (that's what Paul used on his system) that works with vapor to produce a good vacuum, but have no idea if that is possible or not.  In other threads on heatinghelp.com, some other very bright posters have bandied different ideas of how to produce a vacuum.  If there is any way I can create the vacuum without the need for an additional energy source and it is reasonable to create or buy, I will find it and use it or I will create it.  Only time will tell and I like to make stuff, so who knows what will happen?  In the mean time, it will use a 120v pump.



    As for the lines, since I am currently installing the boiler, new pipe and rads, etc, now is the time for me to run all of the vacuum lines while the walls, etc are opened up.



    Currently, I have no idea how long my boiler will run, as I have not even hooked up an oil line yet, the header and about 70% of pipe-work is done, though!  My home is 2800 sf, how large is yours and what area do you live in (are our whether patterns the same??).  If my system will work on 1oz, more power to me and my wallet.  As for venting, I have the venting capacity chart and crunched all of the numbers for proper and balanced air elimination.  My system is rather small, so even the smallest main and even a few radiator vents are too large.  However, the only venting I wanted to do but cannot because of space limitations, is a master vent at the top of my attic riser for the new and largest radiator I added.  Again, however, the radiator vent I am putting on it will quickly allow the air to escape, so I doubt I will have a balancing issue.  Now your probably going to ask, why am I putting on new air vents while at the same time running lines for a Paul conversion?  Simple, I need to have a baseline upon which to compare the improvements or lack there of (which I doubt) when I start using the Paul system.  Again, many folks on here want to know and I am rather having fun doing all of this. 



    As for actually utilizing the Paul system with an oil or gas fired steam boiler, I, like so many others on this excellent forum, really, really want to know just how beneficial it will be versus the cost of install and materials.  I intend on finding out and publishing my results.  Stay tuned.



    Thank you,



    Mike
  • Mark N
    Mark N Member Posts: 1,090
    Steam Injector

    It is my understanding that a steam injector works off of waste steam. If you use an injector that steam used to power the injector doesn't return to the boiler as condensate and that will increase your make up water. That will cause your boiler to die an early death. My home is half the size of yours and I live in New Jersey. I replaced my boiler 3 years ago and went with gas. I had an old Weil-McLain that was installed in the 30's. The new boiler alone reduced my costs by over 50%. A new oil fired boiler would have saved me also but I don't know how much. Here in New Jersey gas is significantly cheaper than oil right now.



    Mark
  • Luv'nsteam
    Luv'nsteam Member Posts: 272
    Steam injector operation

    Hi Mark,

    I hadn't thought about the fact of the steam used to power the injector being from "waste" and therefore not returned to the boiler.  However, now that you make the point, what would prevent the steam exiting from the injector being plumbed into say, a wet return? 



    I think the steam injector works on a venturi principle and thus creates a vacuum after the velocity of the steam is increased by passing through the venturi.  In my tiny brain, I cannot "see" a reason this steam needs to be waisted (only that, in the past, it just was) and this leads me to think it could be plumbed back into the system and I think a wet return would be the best place to allow it back in. 





    The steam injector is a passive device and has no moving parts, I think, except maybe a check valve on the inlet side to prevent back-flow of air pressure, but I'm just guessing.  At any rate, now that I am thinking about it, when the air is drawn into the injector, there is obviously a vacuum on the inlet side and logic seems to tell me there will be pressure on the outlet side along with condensate.  On the outlet side of the injector, I am visualizing a main vent, up high, to allow the pressure to dissipate and pipe to allow the condensate to fall back into the wet return.   And as long as the connecting pipe were began above the water line, a natural water seal would prevent any interference between the operation of the steam injector and the system itself. 



    Your thoughts? 



    Thank you,



    Mike
  • jumper
    jumper Member Posts: 1,592
    circulating air

    Injecting back into receiver just circulates air.

    Ideally you want to minimize air in system.

    It doesn't matter where you pull vacuum from.

    You don't need dedicated vacuum tubes.

    Just tap well above water line.
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