New Mini tube installation

Enreynolds

First, I have to thank Gerry for resurecting the mini-tube system.  Any other installation in our house would have been very painfull.

My house was built in 1926, a two story balloon framed colonial.  It originally had a gravity hot air (octopus) furnace, which I think started out burning coal.  It was converted to Fuel oil somewhere  along the line.  The price of fuel, the inefficiency of the system, and the cold spots all through the house convinced us we had put off the heating replacement long enough.  We considered hot water and forced air, but both required substantial demolition, and my wife has dust allergies, thus no forced air.  Gerry posted his mini-tube system and I had found my solution.

Because of the balloon framing, it was (fairly) easy to pull pipe through the exterior walls from the basement to the second floor.  The only damage that I did to the walls was behind the existing baseboards, in order to drill through the wall plate into the basement.  I used 3/8" refrigeration tubing for both the supply and returns, connected to Governale cast iron (I know) baseboard.  There is a North (131 EDR) and a South {122 EDR) Main branch, with plans for another 30 EDR in the attic in the future.  The mains are 1" copper, and the returns are 3/4" copper.  I have installed a Burnham Megasteam 288 with a 4" drop header for some dry steam

Firing this set-up is a Carlin EZ-Gas burner modified to accept custom Orifice plates for ease of interchangeability.  The gas train starts off with a dedicated 3/4" line feeding the stock Carlin gas valve, through a Brasscraft 3/4" ID flex line, into a Honeywell V5055B gas valve, controlled by a Honeywell  V4062 1008 Hi-Lo-off controller, then into the orifice union on the Carlin.

As for controls, I am using a Honeywell L6081053 0-4 psi Hg Vaporstat, as the boiler controller, and a Honeywell L408J1009 0-16 oz. Hg Vaporstat for the Hi-Lo control.

Enreynolds

Out with the old...

As I mentioned above, we had an old octopus gravity air system dating back  to the mid 20s, so the first step was Demo.  What an ugly job, lots of dust and heavy ductwork.  Much heavier guage than todays sheet metal.  I had figured that the firebox would be cast iron, and we could smash it up to get it out.  No joy.  Firebox was riveted and welded steel.  My aching back.  Somehow my son and I got this 500 lb monstrosity out of the basement.  A couple of dings in the walls, but nothing major.

Enreynolds

...And in with the new

Here are some pictures of the installed Burnam Megasteam MST288, the Carlin burner, and some of the piping.  And of course, my faithful assistant, Griffin.

SWEI

Nice work

I look forward to seeing what kind of numbers you get from the MegaSteam / EZ-Gas combo.

Rod

New Mini Tube System

Hi Eric- Thanks for sharing the info and pictures of your new mini tube system with us. It looks really good!  Like others, I'd be really be interested in your on going impressions of the system and about how the gas setup works out.

- Rod

ChrisJ

LWCO not to code!

You have threads on the bottom of the nipple screwed into the LWCO! we all know thats a no no!



Ok, joking aside thats a beautful work of art!  Can we get a video of the system in action?

gerry gill

looks good,

i think you will need to switch that ounce vaporstat for a pressuretrol tho..is there a condensate tank to put the water back in the boiler? might be hard to keep the pressure down low enough to use gravity return. Mine runs at a pound and a half which is still a big B-dimension. How did you come up with the sizing on the boiler? looks big. I'm not picking on you..i'm thinking we may need some tweaking here.

Enreynolds

Boiler size

Gerry, it means a lot to get a "looks good" from you. That is a MST 288, currently firing to 252 edr. We are planning an additional 30+ edr in the finished attic, putting us right at the DOE of the boiler. I realize that I have essentially no pickup factor on the piping, so that puts us at 30% oversized. I found this acceptable, since we are also planning an addition in the near future.this should put us right in the sweet spot of this boiler. Plus, ANYTHING, is better than that octopus.

The ounce vaporstat is to control the hi/lo firing that I am working on. The 0 - 4 psi vaporstat controls the cut in/out of the boiler. I hope to have this working soon. If I cannot keep the pressure under control at 1.5 psi or less, I have plans to install a pump trap to get the condensate back in the boiler. I think that with Hi/Lo/Off firing, I should be able to stay with gravity return. Time will tell.

gerry gill

ah, sounds good.

I think you will really like it alot. High low fire would be sweet on that set up. Glad your doing it. If you want to get me your email address i can send you the original install manual for the select temp system so you can double check yourself on things. It showed up on my door step one day.

bob_46

Combustion air

How are you regulating the air for hi lo firing? I don't see any damper linkage connected to the v5055.

Enreynolds

Linkage

Bob:

Good question.  This is a work in progress.  You might notice the shaft that is setting on top of the Fluid Power control.  This is the extended shaft so that I can get the linkage to line up with the Air Band on the Carlin.  I have not completely worked out the engineering on the connections, as the spacing is a little tight around the top of the Air Band.  The idea is to use standard Honeywell crank arm and universals to make the connection via a 1/4" push rod.  I invite any and all suggestions to accomplish this.

I have been reading to much of Dave in QCA.  The short answer is "It ain't connected yet"





Eric

Enreynolds

To Dave in QCA

Sorry, couldn't resist

Eric

Paul48

Re: Engineering

Maybe this sounds stupid, but, impress people with how simple it is done.

Dave in QCA

Great Install

Hey Eric!  Great Install!  I have been watching this post for a couple days and trying ot think of something smart to say.  Coming up empty handed so you'll have to take what you get.



Glad to see you setting up gas on a Megasteam.  I really had wanted to use a pair of those in my project, but the whole gas burner thing with Burnham is frustrating.  Glad to see you are working on it and it will be good to hear how your numbers work out.



I too am surprised with the low pressures you are able to run so far.  If in the end you have to turn up the pressure, I have a condensate tank and pump that is going on the "for sale" board in a month or so.  I hope you're able to run without it. 



Working through the calculations on my system which has inlet orifices on the rads, I had to remove the pickup factor.  Also, since there is never any pressure in the rads, I used 225 btu/sq ft instead of 240.  So my calculations for the current connected edr load are 1368.7 Sq Ft x 225 BTU/Sq ft x 1.1 (piping loss) x 1/.81 (combustion efficiency) = firing rate required



In your system, you probably don't even have 10% loss on the piping!



The old octopus must have been a gas hog!  I remember living in a couple houses as a child where we had old furnaces just like that.  The comfort level was actually pretty good because of having no fan and so it was a gradual soft heat.

Enreynolds

That Octopus

Actually ran on oil.  Last year, with oil prices so high, I figured we were paying about  $2.00 more on oil than for the equivalent amount of gas therms.  That was just too much when you weigh in the inconvenience of the oil deliveries and the chance of running out of fuel if the delivery is delayed.  Gas just made more sense.   The gravity air system will work well, if the structure has retained its original footprint.  our house had had some remodeling, which hindered air flow  to some locations, resulting in some cold spots.  I have fixed that with this installation it seems.  Good luck on your install.

Rod

Max EDR Capacity of a 3/8 Tube

Hi Eric-

   How did you determine the maximum EDR or BTU size of the fin tube / emitter that a single 3/8 mini tube could support? 

     I've been thinking about the idea of duplicating the operation of the original Select Temp radiator by using a boost fan system like the Jaga DBE   http://www.jaga.co.uk/technology/dbe

 and am wondering how much the faster distribution of room heat might  increase the overall efficiency of the system.

- Rod

Dave in QCA

Capacity

Rod, that's what I woulda learned if I had gone to engineering school.  So, I don't know the calculation, but, it would be determined by by deciding what is the maximum pressure drop through the 3/8" tubing that would be permissible and still have the anough steam delivered to the convector.  This is a case where cranking up the pressure increases the capacity of the tube.  Also, remember that the pressure drop through a pipe is effected by 2 things, the diameter of the pipe and the length of the pipe, so a short run of 3/8 tube would have a greater capacity than a long one.

Enreynolds

Calculating Pressure loss

Rod, Dave,

I found this pressure loss calculator on line http://www.tlv.com/global/TI/calculator/steam-pressure-loss-through-piping.html

It should help you get where you want to be.  Remember that lbs/hr = 0.31875 X sq ft EDR.  So a radiator of size 100 EDR can generate 31.875 lbs of condensate/hr.  Now by forcing air across the radiator via a fan, you will raise the effective EDR of that radiator.  That calculation I have not looked into.

Based on my calculations 3/8" copper (1/4" ID) 15 feet long will support 28 EDR,  and 1/2" copper (3/8" ID) 15 feet long will support 72 EDR at 2psi.

ttekushan_3

Makes sense.

The SelecTemp model 18 unit heater was rated at 18,000 BTU (or 75ish EDR). With a boiler pressure of about 8 psi, the 3/8" tube could extend from the main and up 2 storeys, delivering both the blower drive and heat.



A much lower pressure will deliver the heat if you remove the "power" component required for the blower. An electric fan is a great idea.



So your calculation of 72 EDR seems just about right to me.



---



I've been chomping at the bit to install such a system for several years, but I don't have the freedom to install something like this under my current living arrangements.



I commend you on your wonderful work!



P.S. Just a reminder that if you're using fin-tube type heat exchangers, you don't need to size the boiler for the pick-up factor at all. As a matter of fact, Iron Fireman (SelecTemp) said to size the boiler on the building's heat loss, not the total output of the connected heater load!

Enreynolds

Chasing leaks

Today I fixed 4 tiny leaks in the system.  It has been frustrating, since  I want to be able to pull vacuum with the system.  After re-soldering those joints, I was able to pull down to 1.8" Hg,  but it did not hold for more than a half hour.  I guess next I will check all of the unions on the baseboards and hope that we can find and seal it all up.  In between, I am working on configuring the linkage for the damper control for the Hi/Lo fire.  There is always something.

Eric

Enreynolds

Progress

Made some progress on the damper linkage for the Hi/Lo fire on the Carlin EZ Gas.  The biggest problem was the tight quarters caused by the air flow proving tube.  I solved this by using some 1/4" copper tube to reroute the tube as seen below.  Not very pretty, as I had to make some tight bends, but it works flawlessly.  Next issue was how to connect the linkage to the Air Band.  I used a small piece of aluminum EL to fasten the swivel to, ground the flat side to match the curve of the Air Band, and fastened it from inside using some #4 machine screws counter sunk into the inside of the Air Band.  Turned out to be pretty ridgid.  Then it was just a matter of bending the linkage to miss the obstructions and pass through the 1/2" hole drilled in the burner cover housing plate.  It did take two tries.  Still to do: Add the stop and adjustment screw for the low fire damper setting, add the return spring to close the damper as the gas valve closes, and set the damper positions using the combustion analyzer.  I added a few pictures to show the modifications more clearly.

ChrisJ

Modifications

Being the system is not only in use in a boiler which is not certified to be used with a gas power burner, and the burner is now modified.  How does this work with homeowners insurance if there is ever a problem?

Dave in QCA

Different than the old one?

While the burner used has not been tested, rated, and certified by Burnham, and so they cannot state what its tested efficiency is.  Nonetheless, the boiler is certified and the burner is certified, probably certified of applications in general that match the specs of the boiler.  Would it therefore be any different, as far as the homeowner insurance carrier is concerned, than the old octopus with a non origial oil burner?

Enreynolds

Semantics

Yes, the boiler has a heat source different than what Burnham sells.  The boiler has a UL rating.  The burner has a UL rating.  All the controls are UL rated.  I have not modified the burner as such.  The air intake is original, the blower is original, all the controls, nozzles and igniters are original.  All I have done is automate the adjustment of the air intake to match the volume of gas flowing into the unit.  This unit is actually safer than the original, as its gas train has redundant valves.  Yes, there is an experiment going on, but it is calculated, and above all, safety is the number one concern.

ChrisJ

Ah

I see. I was asking only out of curiosity.

Enreynolds

ChrisJ

I reread my last post, and It seemed terse.  I did not mean to to snipe at you.  Sorry if it I was out of line.

JStar

Air modulation

I've wondered if the combustion air can be ducted to a graduated round zone damper to control primary air. A lot more control algorithms, but less mechanical movement.



This is how stuff gets done! People experimenting. And like you said...safety first, safety last.

bob_46

Combustion air etc.

Eric , KUDOS

Paul48

Throttling

Have you considered a throttle cable, instead of a long mechanical linkage?

Enreynolds

Cable

Actually, that was my fist plan.  What I could not picture was a clean way of setting up the stop for the low fire position and the return spring.  The mechanical linkage simplifies that somewhat, giving you a solid point to place a stop and a spring connection.  So I followed the KISS path.

Paul48

Mounting

Mount the stop and return spring on the actuator end. With the cable, you could do that on the wall next to the boiler.

Enreynolds

Using cable

That would mean putting the cable under compression to close the air band.  to do this you would need a pretty heavy gauge cable for reliability.  To keep the cable under tension, and thus use a thin cable like a bicycle brake cable, you would need to mount the spring on the air band.  Additionally, I do not see an easy way to mount a stop on the cover mount that will work with a cable reliably.  Maybe you could share a little more on how you envision this setup.  I just don't see it.

Paul48

Cable

I was envisioning a cable similar to one used to connect upper and lower control stations on a boat, but then again, that is a 2 cable system. It would give you positive control in either direction. As for reliability, I would think it would outlast the boiler. I'm just throwing out possibilities. You have your hands on the the job. Good Luck and keep us posted.

     Paul Reynolds

JeffM

burner cover effects

That's a nice looking install. I recently had an EZ-Gas put on my oil boiler, and am curious about the noise reduction effects that the Carlin cover gives. I see you've got the mounting plate for the cover in place. Have you fired it up both with and without the cover in place to hear what the difference in noise is?

Enreynolds

Noise attenuation

Jeff:  To be perfectly honest, I have not fired the burner with the cover on as of yet.  Perhaps this eventing I will try that and see if I can tape it somehow with the cover on and cover off.  My real thrust has been to get the system operational with the Hi/Lo burner adaptation.  But this seems like an easy aside.  I will let you know.

Eric

JeffM

no hurry

Don't rush to put the cover on just for me. It looks like adding the cover is enough work that I won't do it this winter, so I'm not in a hurry to figure anything out - it's just on my mind at the moment so I'm asking questions. Audio files would be super (I can send you my e-mail address if you can't load them up here).

Enreynolds

Got things tightened up

Finally got a chance to work on the boiler again.  Finished up the Hi/Lo draft actuator and set everything up with my combustion analyzer.  On both Hi and Lo fire, I am able to run at 83.2 % efficiency, 9.5% CO2, 4.9 % O2, and between 22 and 30 ppm CO.  The stack Temp is running a little low at 344 F But I think it is close enough.  The Lo fire cut in is set at 0 oz with a 16 oz differential.  I am able to pull 12" Hg of vacuum naturally (~ -6 psig on my digital gauge)  but I still slowly lose vacuum, about 6" Hg/hr.  That should allow me to steam at 200 F on my current 1 cycle/hr.  It has not been cold enough to test if I should go to 2 cycles/hr yet, but there is snow in the forecast tonight.  We will see what happens.  I Will get some pictures and such soon.

ChrisJ

83.2%

I may sound dumb for asking this but, my WM EG-45 atmospheric is rated for 82.9% AFUE if I recall.  What is the point in using a Megasteam and a power burner if it only achieves 0.3% better?



Or is there a lot more to this story that I don't understand?  I mean it seems simple, you measure the amount of heat you are producing and compare it to the amount going out the stack. No?

Steamhead

AFUE ratings for atmospherics

do not count losses from the base and the jacket as losses. The standard assumes that the heat is useful since it is released within the building. Of course, we all know it just goes right up the chimney with the combustion air.



We want the heat to go to the radiators, and a wet-base boiler does that job much better than an atmospheric.



Also, the figures coming off the analyzer refer to combustion efficiency, not AFUE. They are related but not the same.

ChrisJ

Interesting

So for someone like me who has nothing else to compare, is it safe to say that Megasteam is probably exceeding its claimed 86% AFUE rating when compared to my EG-45 @ 82.9% which doesn't include losses that you mentioned?

Steamhead

The MegaSteam

probably does reach that AFUE level. The atmospheric more than likely does not, or would not with a more-accurate test procedure, because the heat lost from the base and jacket does not go to the radiators.