Pressure

crash2009

Mark

I think I see what you are missing.  I consider a developed walk-out basement as part of the square footage.  What do you get if you take 1500 off of 6000?

Mark N

Basement

I don't think I'm missing anything. In the first post of this thread you state you have 435sqft of radiation. Then later on you state you have 377sqft of radiation. If I were you I would go over it again. Even revising the square footage down to 4500 I would think there should be more radiators. An EDR of 377 gets you 20 BTUs/sqft and 435 gets you 23 BTUs sqft. If the heating system was designed for a heat loss of 30 BTUs/sqft, that would come to 562 sqft of EDR. I think 100 years ago they would have designed for a larger heat loss than that. Probably 50 to 60 BTUs/sqft. Considering the house was not insulated. Are all the rads in this house original, or does it look like they have been replaced with newer smaller rads. Are there any convectors? Their output can be tricky to determine.

crash2009

Mark, in answer to your questions,

 the 435 quoted in the first post was correct at that time.  There has been some water under the bridge since then.  Currently I have 377 EDR attached and operational to a WM-EG55.  There is 1 capped riser in this building.  There is 1 rad not being used, it is operational but at this time the inlet valve is shut off and it has been shut off all winter.  I have not decided where to move it, but it is not necessary where it is.  It might as well be called an in stock spare.  All of the pipes in the basement associated with steam are insulated with 1" fiberglass pipe wrap.  This includes mains, risers, dry returns, wet returns, Hartford, equalizer, header. 

There is 1 convector in this building.  It is difficult to size, I guesstimated it.  It is marked on the diagram as 2-BATH.  It is about 30" X 4" or 5".

Over the years, before my time here, some radiation has been obviously removed or replaced.   As I mentioned 3 posts up I did a very rough calculation using the Mills 2-20-200 method and this method suggests that there likely was around 750 EDR in here when the house was built.  This 750 was for the Main, Second, and Third floors.  All this really has nothing to do with today though.  I just wanted to know what may have been in here back then, for a short history paper that I am writing.

What do btu's per square foot have to do with my original question?  which was:

"I did a little test the other day to see what would happen if half of the radiation was disconnected.  I closed the king on main 1.  Main 2 pressured up real good and fast, then something weird happened, The water got real low in the sight glass, so I shut it off just before going into LWCO and auto-feed.

Then I closed the king on main 2.  Main 1 took some time to fill, about 12 minutes and then shut off on pressure about 5 minutes later.  I did not get the LWCO condition while testing main 1.  I wonder whats up with that?  I expected to get the same results."

 

One side shut down on pressure, and the other would have shut down on low water if I had not shut down manually .

Jamie Hall

In response to your question

about what happened with king 1 and king 2 (I do love experimentation!) -- it seems to me that what must have happened is that as soon as pressure started to build (and it might not take much) with king 1 closed, the water in the boiler was being backed out into the king 1 side of the system by the pressure.  Without taking a long hard look at the piping, I wouldn't be able to say from here just exactly why that would be so, but it must be that there was atmospheric pressure and an open vent on that side of the system, and enough volume at a low enough elevation in the system to take a lot of water when the pressure pushed it of the boiler.  And actually, with modern low volume boilers, it might not be that much volume, come to that.  Anyway, with the king closed, that side of the system was not getting the compensating air/steam pressure from the boiler, and up the water went.

Mark N

Shutting off 1 main

Crash you say you have 377 sqft of rads, you have a boiler that an handle 520 sqft of rads. The boiler is 38% oversized right there and that not even taking in to consideration the pick-up factor. Then you shut down one of the mains and then the boiler is like 177% oversized. Nothing good can come from that. Your system intrigues me. You must have the only house with steam heat that the amount of rads might not be able to handle the heat loss on the design day. You can't have any idea how much radiation the house originally had if the rads are no longer there. The Mills rule might get you in the ballpark. I think you live in Michigan. It can get pretty cold there. Since you've lived in this house have you had any days down near 0 with a 20 mph wind. That is the kind of day the original heating contractor would have designed for. To get paid for his work he would have to prove that the heating system could keep the house at 70 on a day like that. If it couldn't he didn't get paid and most likely would be out of business. I think the original design is still relevant because you state the house still isn't insulated and has the original windows.

crash2009

Mark, I think I get your point.

  Either the boiler is not putting out 520 or the radiation is more than 377.  The difference between 520 and 377 is 143. 

Charlie suggested that being unable to build pressure suggests that I have a leak somewhere.  I have been adding 1/2 " about every 7 days.  So, I know I have a leak.  The question is where.  So far there has been no white smoke coming out of the chimney.  The skimmer leaks a bit at 3 psi.  The bottom of the sight glass has been leaking for years.  I suppose I should fix the 2 I know about and move on from there.

The leak was the reason for testing the loops separately.  I thought once I pressured it up, that I may be able to hear or see it.  I was surprised when the water backed out of the boiler before I got up to pressure.

Mark N

Clock the gas meter

Crash why don't you clock the gas meter while the boiler and only the boiler is running to see how it matches up to the rated input of the boiler. Then you'll know. I doubt you are leaking steam up the chimney. My neighbor had that problem and the boiler was going of on low water every day. 1/2 inch in a week isn't much. fix the leaks you have. Check the packing nuts you could be losing some there. The less feed water that goes into the boiler the longer it will last. Have a happy new year

crash2009

Clock the gas meter

  I downloaded the directions.  Clocking the gas meter will tell me how much gas the boiler has consumed in that time frame.  How will that tell me whether or not its putting out enough btu's to heat 520 EDR?

Mark N

Clocking the meter

The input for your boiler is 200,000 btu's. Clock it to see if it is firing at that rate. If the input is low you'll know that the output is low. If the input is high you'll know that the output is high. I would think it is pretty close

crash2009

I clocked the meter

 I used the 1/2 dial.  The indicator went around the dial 5 times in 1 minute.  Does that mean 5 X 1/2 = 2.5 cubic feet /minute?  2.5 cubic feet X 1020 btu's /Cubic foot = 2550 btu's/minute.  Then 60 minutes X 2550 = 153000/hour.  Is this what I was trying to figure out?  What does this mean in relation to DOE capacity 163000 stamped on the boiler?  Is 153000 an acceptable setting?

Charlie from wmass

You want the input rating not

the doe. You should have enough rotations to work out to 200 KBTU's so for some reason your boiler is not firing at full rate. It could be under sized gas piping, a gas valve not opening properly, or set at too low of pressure at the manifold. Assuming your numbers are correct and you are firing 153, 000 btu's input your boiler is say 81% efficient. That is producing 123,930 btu's take a factor of 1.33 for the system That gets us down to 92,947.5 btu's That is only 387.3 square feet of steam. Hence no pressure. So this says to me you need a pro with a calculator ( or a pencil and paper and the knowledge to operate it) and a combustion analyzer.

crash2009

Thanks guys

I believe the no-pressure question has been solved.  I contacted a pro and hopefully he knows how to run a combustion analyzer.  In the likely event, that my math and test methods are confirmed correct by the pro and the analyzer, and changes are made to the boiler to make it put out more.  A few more questions have come to mind. 

Wont this give me the symtoms of an oversized boiler? 

No, you will have the symptoms of a normalsized boiler. 

Will this nescessitate the installation of a vaporstat?

Probably. 

Will this raise or lower my gas bills?

Lower.

What's wrong with leaving it just the way it is?

Waste of $$ up the chimney.

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/281/Undersized-Steam-Boilers

An under-sized boiler can still heat the building

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/290/What-Ive-learned-about-steam-pressure

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/128/A-Steam-Heating-Primer

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/143/Boiler-Ratings-Explained

DOE = Gross, gross is after taxes

http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/service-bulletins/SB0105.pdf

Weil Mclean's are under-fired to begin with.

http://fiainc.com/documents/11-08Howtosizeareplacementsteamboilerandwhy.pdf

Under-fired boiler uses more fuel.

Mark N

Recheck

Crash have clocked the boiler numerous times to confirm your results? If you hadn't stated you had an EG55 I'd a though it was an EG45 because its input is 150k btus. How long does the boiler run on a call for heat from the tstat? How long does it take to make steam? To get steam to the end of the mains? To get steam to the last rad?

crash2009

No, I clocked it only the 1 time that I reported

 I will check it again. 

How long does it run,,It depends on the weather,,,this morning it was on 29, off 69, on 19.  Xmas Day was off 46,on 27, off 52, on 22, off 39, on 24.  December 9 was very cold here 5 F, it ran 40 minutes (I only timed 1 cycle).  The colder it gets, the less off minutes it has.  So I'm thinking that when its 0 F in January, it will run for 40 minutes, then take a little break, then run for 40 minutes, then repeat that cycle until the outside temperature changes.    

My pressure, by the way, when it is in the 40 minute pattern, is usually .05 psi.  I have seen .07psi.  Yes thats less than .1

Making steam,,,On, boil in a minute, steam to header in about 2, steam  to the end of both loops 6 minutes.  Hoffman's often clink at the same time. 

Steam to the last rad,,,,,That's a tough question,,,Do you mean physically the last rads on the end of both loops.  Or the last rad to fill up?  As you can tell there are some balancing issues here. 

Mark N

Last Rad

I talking about the rad that is physically the furthest from the boiler. I also mean the hand valve. The last rad is always the toughest. Mine is in the upstairs bathroom and is twice as far from the boiler as any other rad in the house. Good venting and balance will insure that the rad will get enough steam before the system shuts down. My system is very consistent in how it operates. I leave my thermostat at 70. The boiler always run between 20 to 25 minutes. The time interval between cycles varies with how cold and windy it is outside. Off for about an hour when it around 10 degrees to 2.5 to 3 hours when its 30 degrees. I have a 10oz gauge on the boiler and I read .2oz when running.

Mike Kusiak_2

Boiler sizing and optimum firing rate

Seems like your current firing rate is lower than normal, but is still able to fill all the radiators with steam. This is what Boilerpro proposes in his article:



http://www.heatinghelp.com/article/11/Hot-Tech-Tips/1551/Taking-Another-Look-at-Steam-Boiler-Sizing-Methods-by-Dave-Boilerpro-Bunnell



Are you able to heat the house evenly at the present firing rate? You are probably loosing a bit of efficiency due to underfiring an atmospheric boiler. A combustion test would be able to tell how much, but slight underfiring might still be preferable to having a situation where you cycle on pressure. Possibly the best compromise would be to increase the firing to the point that you build a few ounces of pressure on a long call for heat, but never reach the pressurtrol limit so you don't short cycle on pressure.

crash2009

Well Mike,

the boiler doesn't actually fill them all.  It seems to fill them enough to satisfy the thermostat and keep everybody warm, so I think it's working pretty good.  If low pressure steam is faster than high pressure, then I must have the fastest steam in town.  When it gets cold outside the boiler goes into what I call the 40 minute cycle.  On run 40 minutes and off.  The colder it gets outside the shorter the rest between run cycles.  During these 40 minute cycles the pressure gauge shows usually .05psi  ocassionally it will go to .07    

 This place sounds similar to the last couple paragraphs of the Boilerpro article you sent.  I am sure it was by accident and not by design that the previous Knucklehead set it this way.  I like  the idea of adjusting the firing up, just a bit, rather than all the way to 200,000. 

I read that a boiler can be "red tagged or red flagged" for being underfired.  What is unsafe about being underfired?

This rad in the picture is in 3-A.  This picture is old.  Its not leaking anymore.  Now this rad has a Danfoss TRV and I think I put a Gorton C or maybe a D on it. I may be incorrect about the EDR but It was calculated at 40.5.....I colored the rad with Paint to show where and how its heating.  Red of course is red hot.  Orange you cant keep your hand on forever, and yellow of course is just warm.  The rest is room temperature.  The tenant likes his place 65-68 F and thats what he's got.  If I filled this rad it would be too hot, the tenant would shut it off, or worse open all the windows. 

crash2009

The last rad

 physically would be 1-B (about 60 feet from the boiler on main A) That room is rented, I don't go in there much.  About 2 months ago the tenant asked if I could turn up the heat a little bit.  I went in and felt the rad, it was only hot on 1 section.  The rad vent was only open about 1/8.  I adjusted the vent to 1/2 and havn't heard a peep out of him since (other than the heat is good now). 

The last rad on the other loop (about 50 feet from the boiler on main never cools off.  It always has at least 1 section hot.  Even at the beginning of a new boiler cycle.

It appears to me that the rads here never cool off completely.  They are filled back up before they cool off.  The only pipes that cool off here, are the ends of the dry returns.  They rarely cool off enough to fill the last rad with cold air.  The main vents are about 12 and 22 feet from the last rad.  So I guess I can say (for me anyway) its better to have the main vents closer to the boiler than the last rad.

crash2009

Thank-you

 to all of you that helped me troubleshoot lack of pressure and get me ready to have some.   Mark N for sending me down the meter clocking highway.  Mike and Charlie for their work in the gas section.  I started this thread October 30, 2010 and it has been a great learning experience.  Thanks again.  The solution to my pressure problem is here.  http://www.heatinghelp.com/forum-thread/134484/No-Pressure-Problem-Solved  Solving the pressure problem has revealed problem #2 the leak(s)