School Steam Systems

Owen

My last thread was very productive and useful. I got many suggestions and advice along with very good explanations of some difficult problems. I'm incorporating a lot of them.



Now here's a new one. The High School here is pretty large with six different additions.

There are also three heat exchangers (HX).



The argument is being made, on several fronts, that demand or heating load requires more steam pressure (it's now upwards of 9#) to satisfy all the different areas and the HXs.

I disagree and had the boiler set much lower (3-5#) but if anybody squeaked for any reason regardless of the cause, up had to go the pressure. My way was tried and it failed.



I've saved the District $60,000 in natural gas costs (as determined by the energy nazi) in 18 months, but so far, it hasn't mattered. Keep those phones from ringing.



Are there suggestions on how to address the demand issue? Could demand necessitate higher pressure? Since this is a DDC system (computerized controls) more or less everything comes on at about the same time on weekday mornings (fan coils, pumps, big air handlers, etc) and then is off weekends. The boiler runs continuously every day. Some staggering is programed, but not much. Is that part of it?



Some ares are hard to heat and were having episodes of NO heat.

That's a different kind of pressure.

meplumber

Staging

You have the capability to stage these areas in sequence.



Some facilities, bring up problem areas several hours before the others. If you used your BMS (Building Management System) to bring those hard to heat areas on sooner than the other areas you would your recovery capacity would be extended. By staging the heat on, you are reducing your recovery load.



Several hospitals up here setback office areas and non critical areas during the weekends. While the critical areas are kept at temp. One facility in particular, starts bringing the setback areas online at 2 am on Sunday morning and brings them on in stages, starting with the hardest to heat areas of the building. By 6 am, the entire structure is back up to temp without burying the boiler under the full load of recovery.



Give it a try. BTW, which BMS system are you operating?

Jamie Hall

I stayed out of your earlier thread...

because I'm no expert in these things and you were getting a lot of good answers!  But I'd like to make some general observations here.



First of all, it is a natural reaction of the unknowledgeable, when anything doesn't work right, to try harder.  This is the bigger hammer syndrome.  It's also the higher pressurre syndrome.  It doesn't make it right.  If the system pressure is high enough to overcome friction loss and whatever other head losses may be occurring, that's ample.  More pressure won't help.  I know you know that, but I want to encourage you.  Your way does work -- don't give up.



I may be completely off base -- as I say, I'm no expert -- but I wouldn't be at all surprised if much of what you are seeing in terms of problems arises from the simultaneous or near simultaneous start up of systems.  This imposes a tremendous load; it doesn't work for beans on many types of machinery and I don't see why it would be any different for yours.  Can you do something about staggering the starts, so that one system gets up and running before something else starts?



I know all the above is obvious, but... hang in there.

Owen

BMS

Thanks for posting;

I am not familiar with BMS.



Here the Direct Digital Control system

is AutomatedLogic, Inc. software and hardware installed by

ClimaTech, Inc.

I have very thin understanding of the works, but free access

and some competence.

Owen

Sir

I kinda figured you were thinking about my post.

Thanks for doing so. Politics is the real issue here.

Who has the say-so. I don't, yet.

meplumber

BMS

Owen, the Climatech system is your BMS, sometimes called BAS (Building Automation System.)



I would use that to try staging in the loads, just as Jamie and I are describing.



You hopefully have a company that supports the Climatech system for you. Work with them to setup a staging schedule to recover those setback areas.



Good Luck.

Owen

DDC = BMS = BAS

Okay, got it. Thanks. I figured staged start-up was important.



But what about pressure? Are they right about the need for

more/higher to meet demand or not?

Jamie Hall

Probably not...

but you should go through all your loads and check what pressure they need.  While most won't need anything over 2 psi or so, some heat exchanger or fan coil units may need more (perhaps 5 psi?).  Somewhere -- I hope -- you have documentation on them.  If that is the case correct pressure for them will help -- them.  But your problem as a whole is only going to be solved with spreading out (staggering) the start ups...

Owen

Documents

Right. I'll have to look at the stuff that is available on this building, but I have studied the documents (Original drawings and specs) on other buildings and additions and in the mechanical section the heating units and other equipment is always specified for

TWO POUNDS STEAM PRESSURE!

Tim McElwain

Owen

I find in dealing with politics/heating/cooling I need to have all my ducks in a row. Get all the specifications for the system, contact the Building Management People (BMS or BAS), put together a plan based on what zoning or staging can be accomplished and then present it to the politicians. Dazzle them with foot work and facts along with some good charts and they will shut up and let you do your job. Those who originally designed the system and have left you with the chart you displayed probably had all this figured out. When people start adjusting things because they think they know something then trouble starts. When there is a part of these systems that I am not familiar with I get those on board who know the control system and we work together to convince the politicians. I will be praying for your success, I have been through this too many times so I know what you are up against.

Owen

Thanks.

Very kind of you. I appreciate all the help I get here from you all, and I certainly could use some higher help, even though I probably don't deserve it.

A friend once shared a nugget he got from his dad, "if you can't dazzle with brilliance, baffle with bull s..."

furnacefigher15

Who cries

And when.



That's where I would start. If it's only in the mornings, or only monday morning, then pickup load is the likely problem. If its some other time, then figure out what's really happening.



Once all the areas heat the way they should, then they'll let you tweak whatever you want.



I would see if I could get the farthest area online first. That will get the supply mains primed and ready for all the closer loads.



Start up load is significant, especially in systems like the one you are dealing with.



Also if start load is the problem, you could set the pressure to a million psi, the boiler won't be able to get there, it will just drop to 0 once the loads call.



If they did not factor start up load correctly when picking the boiler, then the only solution is staggering the start times, or getting a bigger boiler (bad choice).

Owen

Preparation is Good

Please know, there isn't a thing I can do right now about steam pressure. It has been taken out of my control. I am preparing, very well assisted by you all, for the time when control of pressure is restored to me.

It may be as soon as the energy nazi finishes compiling his data detailing natural gas consumption since I lost control.

The old way has a definable cost, as I mentioned, over $60K in 18 months, when I was running around trying to get a handle on this stuff. It wasn't hard to find outrageous excess and waste. "The Tragedy of the Commons". Everybody owns it, so nobody takes ownership.

The next few weeks may be interesting around here.

But at any rate, these discussions are excellent tutorials. I appreciate it very much.

icesailor

Tutorials:

They are great tutorials for some others of us reading this.

Us Techno-weenies.

Thanks for keeping this informative discussion going.



CMG

furnacefigher15

Check out this video

http://youtu.be/a0xZPl_bwHI



Inside of steam boiler. Very Cool.

Owen

Pick-up Load

These wonderful posts explain a lot.



This boiler bounced/surged continuously when I had control of the pressure, and still does.



I had it programmed so at night and weekends it would fire only enough to keep it at 180º;

so all that piping, and there's a lot, the mains start at 8", would cool down;

when it started to run at pressure (2-5#) in preparation for Monday AM school it would start to bounce like crazy.

That would cause LWCO to trip. A couple of times the LWCO tripped late Friday or on Saturday early AM. Then things would REALLY cool down, so then we show up and the damn boilers cold, the boiler rooms cold, the building is cold and they're starting to call the boss bitching, which gradually gets more intense...

Several of us are standing there and now the sight glass level is going bonkers and LWCO shuts off over and over while the boiler struggles to make pressure (pressure is everything around here). This goes on for hours sometimes. What's going on??

THE PIPING IS COLD TOO! Pick up load!



Apparently you can't do everything at once. Boilers don't muli-task.

Solution: Staging, staging, staging.

As I understand it now, heat piping first (Pick-up), then farthest radiators (the oldest section), then the closer steam system with F/C units, then the farthest HX, then next HX with the most feet of pipe going to it, then the biggest one.



Also venting at the extremes of the piping would be important for pick-up load heating.

Then the rads. (They work great, I wish the whole thing was rads, but they don't ventilate for breathers.)

There's another Post!

Jamie Hall

Hang in there

good buddy -- looks like you are on the right track.  Now if the powers that be will let you keep going...

Steamhead

Water's probably dirty

The pick-up load happens out in the pipes, so by itself it wouldn't cause the boiler to surge. You either have dirty water in the boiler, or wrong near-boiler piping, or it's over-fired.



I recall you're using some sort of chemical treatment in those boilers. Too much of this can make the boiler surge. If, after skimming the boiler it still surges, drain it out, refill with just water and see if it still surges. I bet it doesn't.

Owen

Chemicals

Gosh, I gotta be careful here. If I say anything to my water treatment specialist about what some are saying here about chemicals his BP goes crazy.

But anyway, no such luck. This thing has been drained and refilled many times since it was put in, many. Also, earlier this season we stopped adding chemicals and let the level go to zero and it had no effect. My boiler guy suggested that long ago, so to prove to him it wasn't improper chemical level we let it run for severl weeks with nothing. That scared the s... out of me because it's taking on so much fresh water (3-10 gallons PER HOUR).

I know finding the leak is critical but nobody but me seems too worked up about it. That and it may cost a couple hundred to rent a thermal imaging camera, since that's what it's

down to. Everything else has been looked at or checked.

Sorry, not chemical. If only it were that easy.

Owen

Keep Going...

... right out the door. Boat rocking is making some big waves; I hope it doesn't swamp my little dinghy.

All I ever wanted was to be left alone in the boiler rooms to do my thing. But no, everybody's an expert, especially those who don't know anything.

All this reminds me of Dan's "Smokey" character, or as Tom & Ray "the tappet brothers" say: "unencumbered by the thought process".

The reference is to Tom & Ray, hosts of Car Talk on NPR. If you haven't listened to them, check it out, Saturdays. Very funny, with answers!

Steamheads need a show like that, what-da-say, Dan?

furnacefigher15

Watch the video

I had in my last post.



The same is true for any boiler.



If its sitting idle and at pressure, and all the sudden, there's a huge demand (pressure drop) on the boiler, the water will start boiling like mad, and the water line will swell contributing to the carry over problem, and whatever you can see in the gauge glass, it will be ten times worse inside the boiler.



He's got a tremendous pick up load on that boiler. And I fear, it may be too much for that boiler to handle.

Mark Eatherton

Over fired....

Once you eliminate all the usual suspects (cheimcials, dirt near boiler piping), look at the fire, and see if it is significantly over fired. That too will cause water to jump up and carry over.



Also, if you have a BMSPC in place, there is no reason why you couldn't do an outdoor reset based on either steam pressure (more difficult) or steam temperature (much easier, and as reliable). You don't leave your vehicles idling at 5,000 RPM when you are going 20 MPH, why leaving your boiler maxed out when its not that cold outside...



I know, smack you self on the head, and don't ask for permission... Frustrating position to be in for sure.



ME

Owen

Spirex Sarco Video

I love this clip. I've seen it several times since

YouTube actually has lots of responses to a "Boilers" search.

I knew it was happening but didn't know what to do about it.