Heating Help

Vacuum experiments

@ January 18, 2012 8:15 PM in Another Look at Vapor Vacuum

The only setting I had at my disposal in the past for experimenting with vacuum was in an old building with store fronts and 2 floors of apartments above.  The boiler room was in a sub basement on one side of the building, feeding a long main with three drip stations, each station being at a transition in the elevation of the main.  I rented a store in the middle of the line and had one of the drips in my basement.  I had access to the boiler room and to my own basement only, so anything done had to be in one of those spaces.  Anyway, it was a basic two-pipe system with traps at the drip stations with one dry return, gravity return.  [We took the system back to gravity when the boiler feed pump failed]

So it was a long, linear system with a significant time delay between heating of the tail end versus the beginning.  The room temp diff from one end to the other was about 7 or 8 degrees F if I recall correctly.  Noteworthy was the delay in the steam getting past the "hump" at the drip station in my basement.

The purpose of the experiment was to see if I could even out the steam distribution and speed the pick-up time given that the boiler was slightly undersized.

Enter SHOP VAC and hoffman 76's vacuum main vents.  Now, this system was NOT tight by any means (valve packings mostly) but I couldn't control that.  Therefore, the vac did not run all the time the boiler was running, but only triggered by a thermal switch somewhere along the main and operated on an adjustable time delay relay.

The thermal switch was located in my basement on an uninsulated radiator riser.  The boiler would fire, begin producing steam, and when the steam made its way part way down the main, the shop vac (attached below the return vent through a swing check) would turn on.  The boiling at the boiler became audibly vigorous, and the steam would now charge its way down the rest of the main and up the risers.  The timer was adjusted to allow the vac to run long enough for a section or two of each radiator to heat. 

This was quite instructive as it proved that the balance of the system was maintained in the absence of vacuum, so long as each radiator started condensing at the same time.  I think this is the key to the Paul system as it both does some of the "pick up" work and gets all the radiators on equal footing early in the cycle.

Once the boiler shut off, a mild vacuum (maybe 2" Hg)  would develop for long enough to cool the boiler some.  A further evening out of the room temps would occur at this time.  The temperature differential from coolest to warmest dropped to 1.5 to 2 degrees F.

The experiment proved three things:  1)  That vacuum return evens out temperatures, 2) Vacuum return shortens the "pick up" time required and total boiler run time, 3) The building temp could be dropped a bit since no one was cold anymore, and 4) I wanted to learn a lot more about vacuum (including both naturally induced and subatmospheric) operation of steam systems.

===

In the absence of a vacuum pump, it seems to me that the system would have to be pretty tight for naturally induced vacuum to produce even temperatures as running the system to saturation (all rads filled with steam) to get the vacuum initiated.

So this brings me to an idea that I had regarding Gerry Gill's mini tube steam system (I'll cross post this to that thread when I get a chance):  What if we introduce a pressure vessel akin to a reservoir tank whose sole function is not to collect condensate but to be an air/vacuum moderating chamber, say, large enough to limit the depth of the naturally induced vacuum created by the system without readmitting any air.  At this point we may be able to achieve a system with hermetic characteristics and the benefits thereof.  I would really like to not have to blow down a boiler anymore!

I've seen this on the LGB

@ January 18, 2012 6:50 PM in Boiler's fluttering gas tubes

under several circumstances.  1) leaks between sections causing rust and rusty flakes to restrict the fine slots at the top of the burner, 2) the boiler was modified to operate with only one ignition module and therefore only had one point of ignition on the far end, and 3) the internal regulator on the PV MV  Honeywell gas valve has gone bad-- meaning that the turn-on of the gas is no longer a gentle two stage affair, but a sudden "woooof"-- and  will cause the gas to burn within the tube, especially on a cool start.

Most troubling in scenario 3 is that the manifold pressure may not be regulated anymore.  I recommend that you get a technician there to look at the wiring and be sure that the manifold pressure is not exceeding the  3.5" w.c. specified.

I suspect

@ December 28, 2011 2:58 PM in Do I need a condendate tank

that the heating contractor wants to install the tank/pump in order to separate the return system from the boiler so that he can crank the steam pressure UP in order to force the steam through the mis-piped radiators.

This will decrease the efficiency of the system.

Furthermore, it is doubtful that such a fix will work quietly, and will more likely cause water hammer in that area and possibly other areas you didn''t have troubles in before.

A condensate tank in and of itself has no impact on the efficiency of a steam heating system.   It is often necessary for other reasons, typically in large installations with far-flung zones of heating, grade differences, etc.  If it works well with gravity, that is absolutely the best way of operating the system.  I have removed them more than installed them.

No need to name names

@ December 27, 2011 11:25 PM in Overflow trap conflict-what to do

since I was really looking for some insight.  Besides, no one from that manufacturer has yet come out to the job site.  The equipment company wants to get a rep out to the site to meet with everyone after the holidays. 

I prefer to give everyone the benefit of the doubt, and this manufacturer has some of what I consider to be some of the best products out there in steam world.  Our problem appears to be with one series of boiler's installation manuals, and I don't know how that happens.  I have no reason to believe that the boiler won't be quite satisfactory once these issues are straightened out.

Also, our ultimate solution costs nearly nothing to implement.

Oh, and that defamation/lawyer thing. ;-)

Like you,

@ December 27, 2011 9:53 PM in Noisy Hot Water Loop Off Steam Boiler

I have fun finding the best way to add onto a steam heating system when rooms are added or extra heat is required somewhere.   If the boiler has the capacity, you can usually find a main that has extra capacity, or an alternative piping method, etc. to do it.

The trick is knowing how to do it ;-)

Sometimes I feel like a Steam Zombie, like the "living Dead Men" are speaking through us - "you can do it."   Or maybe I should speak for myself on the zombie part :-)

Happy New Year

Thanks Gerry

@ December 27, 2011 9:37 PM in Overflow trap conflict-what to do

for you input.  I've added that to the options.  Unfortunately, there was only one guy at the equipment company that I was convinced knew his steam and he retired two months ago just after selling this job.  Now there isn't anyone to go to bat for us with the Famous And Reputable Boiler Manufacturer.  Said Manufacturer "doesn't make mistakes."  So there. [with the sound of boiler feed pumps cycling endlessly into the sunset]

Inasmuch as this scenario has developed the feel of Tim Burton's movie, "Brazil," we are going to do a little work around that involves lowering the water line slightly to solve both the trap level problem and the nasty surging habit these boilers have, even with clean water.  Though the Famous And Reputable Boiler Manufacturer doesn't acknowledge the issue.

With the help of you and others who wish to be and shall remain anonymous, I've been able to discuss the issues associated with this boiler series with one of the many contractors involved in this installation who is willing to just make it work the way it's supposed to. 

Happy New Year

"N" is for Nowledge!

@ December 27, 2011 9:14 PM in Review by "experts"

One would think that with two weeks to complete the exam that you should be able to at least muster a passing grade of 70% without taking the class.  This is not to diminish the content of the course in any way.  On the contrary, it proves the value of it since you might have to hit dozens of sources to find the information needed to pass the test.

So... they don't have the requisite knowledge AND they haven't mastered the art of research.   I'm ignorant of all sorts of things, but I like to think I've honed my ability to find the answers, as I suspect everyone else here on heatinghelp has.  Why else would we be here?  To help and to learn.

Its a sad commentary that they won't avail themselves of Tim's expertise, but let me take this opportunity to say that, though Tim has never heard a peep from me before, I have read his posts here on heatinghelp for years now.   The problem-solving context that these forums provide Tim's answers make everything make all the more sense.

So Tim-- thank you.

Overflow trap conflict-what to do

@ December 20, 2011 1:27 PM in Overflow trap conflict-what to do

Hi!

Here's a conundrum and I'm looking for some insight from others out there on this one.  So I'm consulting on a dual steamer installation, and the contractor and subcontractors did a lovely job on the steam headers, etc. but did not install overflow traps on those boilers.  Each boiler has its own feed pump with check valve.  The burners are sequenced electronically.  Not surprisingly the "off" boiler would flood.  I suggested overflow traps and to support my suggestion, I had to contact the Famous And Reputable Boiler Manufacturer's rep to get the sheet that shows the traps' installation since this information is not in the basic I/O manual.

Here's where it gets weird.  The installers welded in the thread-o-lets into the equalizer, and piped the traps. 

But they installed the traps at the normal water level, not above it by 2 or 3 inches the way I certainly expected.  Every installation and installation manual that I have seen in addition to Dan Holohan's "Lost Art of Steam Heating" (and I presume the ASME code) calls for the trap to be above the normal water line by about 2 to 4 inches, depending on water content.

And the biggest problem-- the installers followed the manual.  Here's a couple of screen shots of the Famous And Reputable Boiler Manufacturer's instructions plus a couple of shots of what I would expect to see in their manual. 

Predictably, the feed pumps run way too frequently, and worst of all,
the boilers short cycle at high fire since the pump kicks in several
times in short succession and the water line drops for a moment as the
steam bubble column within the sections collapses and resets the power
burners.  So they boil for a minute, and then post purge, pre purge,
etc. for two minutes.  Obviously a real problem

But the manufacturer clearly states "at normal water line."   I believe this to be in error, but the installer is inclined to believe that it is not their problem.

How would you proceed?  Any thoughts are appreciated.

P.S., I have been remiss by not contributing much to the forum in recent years, but when I read it, I find the questions already answered by a crew of very capable and knowledgeable "regulars" here that I find I have nothing to add.  The art of steam is in good hands here at heatinghelp!

It may be worth

@ December 13, 2011 12:26 AM in Vents woke up on the wrong side

revisiting this thread:

http://www.heatinghelp.com/forum-thread/138703/Gorton-Vents-venting-slowly

the first microswitch type

@ November 25, 2011 5:42 PM in Another Vaporstat Question

vaporstat I ever installed did just this.  Even when reducing the differential, it would stick "off" at lower settings.   I was irritated and it was late, so I carefully took a fine diamond file to the surfaces that rock and forth. They seemed very crudely made, as if stamped and never finished.  To complete the task I lightly lubed the parts with TriFlow which has some teflon in it.     

Well, it worked. That control works fine after 5 years and I've done the same thing to a couple others with success.  That same crude finish must be what caused problems on the last of the mercury switch versions as well.

FWIW.

Heat loss, Friday funny

@ May 20, 2011 10:08 AM in Heat loss, Friday funny

Or should I say, "heating hell?"

Sounds like a box boiler

@ May 17, 2011 11:59 PM in Old Kewanee for repair

We worked on a Kewanee box boiler several years ago that sprung a tube leak. 3R5 model if I recall correctly.

If it was mine, I would have had it retubed and put a modulating burner on it, but the owners decided on replacement, since it appeared "ruined," particularly that water leg area around the bottom. It apparently leaked long enough to make things look pretty bad. Upon demolition, I saw that the fears were unfounded as the steel showed no thin spots. Thinner than new? Probably yes. But it was so overbuilt, I think the steel was still thicker than some of the cast iron sections on new boilers.

A full evaluation needs to be made by someone familiar with firetube boilers. My concern with old boilers is not so much the vessel (since the pressures are so low), but with the proper function of the safety controls, like the pressure controls and low water cutoff. Furthermore, some of those box boilers had less sophisticated burners which are usually less efficient and less safe than the large commercial burners or modern units.

For some reason or another, I felt bad about the demolition of that old Kewanee box boiler. I marveled at how well built it was as it was being cut apart. BTW, the owners have said that the fuel savings with the new boiler are not very impressive.

Terry

I would add

@ March 27, 2011 2:48 PM in Legionellae article

that the normal background level of legionella is not the problem. Thats why we don't have problems with the cold water supply.

We create the problem by interfering with nature by actively heating the water just enough, to a temperature that promotes the rapid propagation of the critters. After cultivating this bloom we then store it for the first hapless shower-goer. The shower head dispensed "legionella concentrate" aerosol is the problem.

We need to solve this problem since this is one of those we have created to begin with. Since the solution is so simple, it seems to me that it bears doing.

and another thing:

@ March 26, 2011 10:54 AM in Steam versus Hot Air

Tuning up the steam system is just the beginning of the process. Check out the Interfaith Coalition on Energy.

They have extremely effective advice as to how to properly and efficiently conserve energy in sacred structures. Good stuff there.

Here's what happened

@ March 26, 2011 10:43 AM in Steam versus Hot Air

at a church where they did just what you describe due to getting air conditioning and the heat package was "almost free" in the scheme of the total budget. [I found out about it since they had 55 radiators for sale] As you surmised, lacking a radiant heat component at floor level, the choir level would rise to 85 degrees to keep the floor level at 65 degrees. In desperation, they installed tiny ceiling fans waaaay up at the ceiling which, of course, were of psychological effect only.

The full effect was not known until it was too late. The next season, they had to install electric baseboard heating throughout the offices and restrooms, and other utility areas because they were inadequately heated with the new system. In talking to an old timer there who kept up the steam heating system, it became clear that the comfort level dropped substantially and that the increase in electricity consumption more than offset any savings in natural gas.

They should have kept (and optimized) the steam heating system they already owned and kept the forced air for air conditioning only. Best of both worlds.

vacuum

@ March 5, 2011 12:49 PM in New steam mini tube system installed in my own house. (Iron Fireman style)

The extraordinarily low volume of this system would be of benefit to applying vacuum, too.

Let me get this straight.

@ March 4, 2011 11:52 AM in New steam mini tube system installed in my own house. (Iron Fireman style)

EDR is based on the heat loss of the house;
The boiler is fired below the EDR;
The system is operated with "forced air" heat anticipator settings;
The boiler doesn't run any more than the 100K BTU furnace that it replaces;
You are heating a say, 1500 square foot house (1920's vintage?) with 46,000 BTU input.

So.

Why is this not being installed everywhere, both from a first cost and operating cost standpoint?! (I don't expect anyone to be able to answer this)

This is the perfect system for the "apples to apples" comparison of modern steam vs modern hydronic vs modern forced air that Steamhead has spoken of. I really think that a steam minitube system could turn out to be a real winner in both first cost and operating cost.

Performance updates now that February's ending?

@ February 28, 2011 5:10 PM in New steam mini tube system installed in my own house. (Iron Fireman style)

Hi Gerry!

You have certainly had some time with the new steam system-- and I've been wondering how it has worked out in the cold temperatures. Do tell-- how has the comfort level been? Has it heated well in zero degree temperatures without going above 2 psi? What is the firing rate on the boiler now? Do you think you could have done without the condensate tank in this instance?

Enquiring minds want to know. . .

Tekmar 279

@ January 14, 2011 12:10 AM in The Plan so far..

I like the 279 a lot, especially with indoor sensor(s). It has a built in time clock for setback if desired and it alters the recovery "lead" time based on how the building recovers temperature over time. I also like the fact that warm weather shut down temperature can be adjusted independently of interior set temperature (unlike the 269 it replaces).

ALSO, a very nice feature is that when using an indoor sensor, the control can alter the total cycle length based on how the building temperature responds to the boiler's operation.

Nice control.

If it worked right at all

@ January 13, 2011 11:23 PM in I thought we did everything right. What do you think?

it will work right again. A quick glance a the photos don't show any piping problems.

I think you're chasing oils and other occluded contaminants around the system. That's why it shows up after a period of time. It's aggravating, I know, but stick with the skimming. When I've encountered this, I fashion a surface blow off valve at the skim port and run it to a drain. Crack open the valve and let it spit for awhile with the boiler running. Obviously, observe basic safety measures, like keeping children, pets and clients from the steamy parts. You might leave the valve there, capped or plugged for future reference.

Just my 2¢

P.S. I like to run counterflow systems on a vaporstat and slower venting of everything.

EDIT: and for idle curiosity, how are you venting these boilers? It's hard to tell from the photos. You shouldn't encounter condensation on steam equipment exhaust gasses, but I've not dealt with these new side wall vent type steam boilers yet.

Mouat valves

@ January 12, 2011 12:23 AM in new to steam

Well, I had a very lovely post for you, but it got lost in the aether.

Suffice it to say that you have an orifice vapor system. We see these often in Cleveland. EVERY valve in the system should look like that Mouat valve. If any have been replaced then the heat distribution will be very wrong. An easy way around it is that if there are any standard valves that replaced the MOUAT valves, then close them and then open them about one half turn or so and see if this evens things out.

Also, you shouldn't have any more pressure than 4 ounces or so, so you really should have a vaporstat instead of the pressuretrol that you now have. This explains the rusty stains above the vents. The mouat system typically didn't have end of main vents, but end of return vents only. From where those vents are, look straight down and you should see a short pipe that connects the steam main's drip leg to the return. That line MUST be below the boiler's water line. The depth below the water line and the low steam pressure keeps the steam supply isolated from the return. What is happening here, I think is that that loop seal is getting blown out and closing the vents, at which point any cold radiators will stop heating any further.

Rectifying these minor issues should straighten out any problems. Also watch that that cross link pipe between the main and return is not partially clogged. That can cause some vexing problems too.

EDIT: look at the water line of the old boiler as compared to the newer one. Now look at the height of the lower loop seal on those pipes on the wall (below the red circle). The supply is short circuited to the return. As it is right now, it looks like the steam is quickly traveling the length of the main and then finding its way to the vents. The system is then air bound, and your run time will be very long, as well as the fact that the steam will be nearly stalled before it reaches the second floor. Very inefficient.

You MUST have a vaporstat installed and you have to either lower the return system or install a false water line (preferred). All of this is outlined in Dan Holohan's books. It really isn't that difficult.

brilliant.

@ December 17, 2010 8:48 PM in can anyone identify this mouat part?

why didn't I see that? And quite a high resolution gage at that. Kind of like the one you fashioned for your minitube steam system.