The Gorton #2 Saga Continued

steam-rookie

I would like to thank jpf321 for stopping by my house. JP drove from Queens to Long Island for a nice friendly 3 hour chat about my steam system. JP is a Cornell University graduate with a very intelligent and scientific approach to the art of steam heat. Together we were able to determine the following:

JP calculated the total EDR of the convectors in my house and it is about right for the current boiler that I have.

I now know where the tank-less coil is, and with that knowledge, it appears that I will be able to replace it myself, sometime in the future.

JP explained to me how to set up a pc of clear tubing from the bottom drain of the boiler up to the ceiling. This will show how high the water is being pushed up the return towards those brand new gorton #2`s.

We think that it it very possible that it will show that the water is being pushed up way close to the vents. This could most likely be the cause of them not closing.

We lowered the pressuretrol and got the max pressure down to 1 psi and the cut in to 0 psi

this did have a significant quieting effect on the G2`s. Quieter, but not silent yet. We were however on to something

JP suggested a vaporstate on the system. After much discussion, I finally now understand the advantage of running on very low pressure. The vapor stat is a very expensive option for me right now so I will be trying something else that we discussed. First I will be trying that tubing test to see exactly how far up the water is going on pressure. I will then be adding a 6 inch nipple to the top of my main to gave me more height above the water level. At this point I will have to extend my antler arrangement to the right about 2 feet and then I will have the necessary height needed to add the G2`s up between the floor joists. I will post a picture when I am done.

I am hoping that this will stop the G2`s from leaking.

One last thing. After JP left I lowered the pressuretrol even more. The cut off pressure is now under 1 psi. However, With this new low setting, the cut in pressure is under the 0. I think this would be considered negative pressure.

This is my question: Is this a bad thing? Is it bad to cut in under the 0?

Should I readjust it to cut in before it drops below 0 psi??

gerry gill

thats great news..adjust

the pressuretrol as low as you can go and still have the differential actually still restart the boiler..you can adjust that spring so low it cuts the boiler off but it won't restart..see, its steam that does the heating, not pressure..your on to something that we have a very hard time getting thru our contractors heads..pressure is not good, steam is good..

Unknown

Checking your Gauge and Settings

You can also use the clear tube method to check your pressure gauge and pressuretrol settings.  Mark a stick every 1 3/4 " and set it up on the vertical so the zero point is aligned to the waterline in the tube when the boiler is turned off.  Each 1 3/4  of height above the cold water line level represents 1 oz of pressure.   

1 PSI = 28 inches  

2 PSI = 56 inches

jpf321

a nice visit indeed ...

a few things to note to reader in general



1) SR has only 1-pipe convectors in his house .. i'm not entirely sure how to properly vent/balance them.. EDR on convectors seems to have alot more to do with cabinet size and height and alot less to do with actual steam volume .. I see that in the Gill & Pajek paper, convectors contain very very little air volume/sq ft. I will have to run my spreadsheet with the data from the G&P paper.



2) We measured SR's Dimension A to be just about exactly 28" .. but he was also running at over 1psi on his "high pressure" cut-out of 1.5lbs .. theorectically 1.75" x 24oz = 42"!! .. now that wasn't backing up to his vents .. but it was backing up into his mains potentially...maybe even into his rad risers .. wow I didn't realize it was quite so high.



3) I did bring my Gorton #2 and a Gorton #1 .. the Gorton #1 closed up and was silent even up to 1.5psi .. the #2 on the other hand (although silent on my 5oz system) did hiss and spit some on his 1.5psi system .. we then tried another experiment .. with ...



4) WD-40 in my gorton #2 (since I have no intention of returning it, and he may still return his) .. with the WD-40 liberally sprayed into my G2 we think it stayed quieter overall even up past 1psi.



5) Going back to #1 above .. can someone like Mr. Gill explain to me about convectors and EDR and boiler ratings ... it would seem to me that with such a small volume of steam in a convector, that the boiler rating may be significantly off .. if a boiler is rated for 360sq ft of EDR, does that still stay the same with a convector system? convectors have miniscule amount of volume needs compared to regular rads.



6) SR lacks a hartford loop but because of his design, I don't think he needs one .. his wet return drops just a few inches from the boiler .. and since the purpose of the hartford is to keep water in the boiler in the event of a wet return leak .. and since the hartford is often a few inches from the boiler anyway, it seems that having his return dropped so closely does pretty much the same thing ..



SR .. please email me your individual EDR's that we calculated so that I can run it in my spreadsheet .. along with the length of your main .. Thanks, was great to meet you .. I have to end this prematurely since my lappie batt about to die .. if I think of more, I will add to this thread ..

malp

equilizer

The equalizer pressurizes the return to the same pressure as the header. Water stacks up in the return at the end of the main only enough to overcome frictional losses from the main piping and returns. So, the water level is only affected by the pressure drop from one end of the main to the other and not by the absolute boiler pressure. Unless you have a 2 pipe system. They're usually always open to the atmosphere at some location, so boiler pressure does affect how high the water piles up in the returns.

malp

duplicate

duplicate

djthx

Clear Tube Pressure Gauge

Questions regarding these clear tube gauges:



Rigid or flexible material?

Tube size?

Connected at the boiler drain?

Should top of tube be capped or open ended?



Thanks.

steam-rookie

The Tube Test

The tubing is the flexible kind

The size is determined by the fitting that you get. One side of the fitting screws on to the boiler drain, the other end is either barbed or compression. This other end will determine the size of the tubing

Connect to the boiler drain because that is the lowest point on the boiler.

Top of tube is held up (however you can, maybe a wire tie) at basement ceiling height.

Tubing is not caped. leave it open

I hope I got all that right. I will be attempting this today, and will post a picture

My goal is to see exactly how far up the tube my boiler water is being pushed. This will in turn tell me how far up my return pipe the water is, and his will tell me how close the water is coming to my main vents.

I also have a very good plan to get those main vents higher up and away from the water.

steam-rookie

Thank you MALP

My system does not have an equalizer. I have heard them mentioned many times and never knew what their purpose was. Now I do. Although my boiler does not have one, I do. Its called Bacardi and coke, the great equalizer.

jpf321

hose fittings

Here are two options for hose fittings .. I believe that Home Depot has the barbed for 2x the price of the compression.



Make sure that you get the proper tube while you are standing there in the brass section. Unless you have an abnormally tall basement or are running at pressures higher than 3PSI, you only need a 10ft length of tubing. http://www.homedepot.com/webapp/wcs/stores/servlet/Search?keyword=clear+tubing&catalogId=10053



Lastly, please note that you can put this tubing set-up (manometer) on any hose bib you have which is normally below waterline .. it just happens that SR's is on his boiler drain/return.



BARBED

$8.39 http://www.homedepot.com/h_d1/N-5yc1vZ1xj8/R-100637888/h_d2/ProductDisplay?catalogId=10053

$7.43 http://www.homedepot.com/h_d1/N-5yc1vZ1xj8/R-100637982/h_d2/ProductDisplay?catalogId=10053

http://www.plumbingsupply.com/images/fht-barbed-swivel-hose-fitting.jpg



COMPRESSION

HD does not seem to list them on website .. but I know they have them for 1/2 cost of above.

http://www.plumbingsupply.com/images/hoseadap-fht-compression-swivel.jpg

steam-rookie

clear tube test

The clear tube is installed. This is a very accurate and interesting test.

Mr. Rod posted that 1 psi = 28 inches in the tube

My cut off pressure 14-15 ounces.  that would equal 27"

From start of test to finish, THATS EXACTLY how far up the water went.  27"

This 27" rise puts the water 1 inch from the main. As you can see in the picture it is just under the elbow.  That seems mighty close to me.

Since JP was here on Saturday I have reconfigured my antler.

I put a 8" nipple on top of that elbow, from there I shot a 30" pipe to the right.

This allowed me to raise the new G2`s up higher, between the floor joists.

From that 27" mark, I now have exactly 12" to the level of that 30" pipe/vents

The G2`s are now significantly quieter. However, they are not silent yet, and that is my goal.

Now I will ask more questions:

1. Is the 30" antler extension a crazy idea?

2. If its not crazy, how much of a pitch should I give that antler? 

3. Current settings on my pressuretrol, the boiler cuts out at 14-15 ounces

It is cutting back in under the 0 psi (negative pressure).

Mr gill mentioned that as long as it cuts back in its OK

On the other hand, I have seen a few posts that have frowned on dropping below the 0 on cut in

I have also seen a few posts that state , the only time the system should see negative pressure is when the thermostat is satisfied.

Is this a controversial subject

What is the correct answer?

Dropping below 0 psi before cut in, between cycles, is OK, or, No Good. ??

jpf321

great job SR

Just for curiosity sake .. can you pump the pressure back up to 1.5psi and see what happens to the water level?



I agree with Mr. Gill .. as long as you go back on .. then you're OK .. but I am a bit worried about dropping below 0 .. since if it doesn't go back on one time, you may be in trouble, and not know why you aren't firing.



the long antler is fine .. just enough pitch to get it back i'd say .. you may do well by putting a "close nipple" and then another elbow of your current elbow on top of verticle .. so you have up and down movement capability. basically take the elbow you have now and point it toward the front of boiler .. add on a short nipple and another elbow then your long pipe into this second elbow which can now swing up and down. (otherwise known as a swing joint I believe)

steam-rookie

30 inch antler

I plan to use the swing joint idea on that antler. Is there such a thing as to much pitch, for an antler?

If I raise the pressure to 1.5 psi, the water in the tube will go 14 inches higher. That would put it right at the ceiling, and possibly blow out the top of the tube.

Does dropping below 0 psi mean that I am in a vacuum situation

I will quote a very recent thread by Anthony called boiler in a vacuum

Quote:  Ted

"One-pipe systems with main and radiator vents should never run a vacuum.

See "The Lost Art" for details on vacuum systems."

 

steam-rookie

Negitive pressure

Anyone have an answer on the negitive pressure issue?  Please check my last two posts.

Steamhead

Don't go negative

this can pull air back into the system. Tune your pressure cut-in point so the burner fires in time to maintain a couple ounces at the boiler. 

steam-rookie

Thank you

I feel that I have just received the ultimate answer to my question from the steamhead himself.

I will be adjusting that pressuretrol tonight.

I had a feeling that dropping under the 0 was not good.

This brings me to my next question.

When I adjust to the new cut IN setting it will automatically change my cut OUT setting. This is just because I am dealing with a perssuretrol that is as low as it can go on the cut OUT. I believe that I have reached the point that I will be needing a vapor-stat to control the pressure on this boiler. I am assuming that the vapor-stat can maintain the max pressure at around 12 oz and still cut the boiler back in before it drops below the 0. Is that correct?

I might as well ask now. What is the very best vapor-stat that can be had?

Also, just out of curiosity, Do you think that this boiler originally was designed to have a vapor-stat on it?  Do you think that sometime over the years that it got changed out for a pressurtrol by some knucklehead

jpf321

that pressuretrol

that p-trol is really really really old ..



yes the vaporstat is the proper device .. there is really only one model available .. [url=http://customer.honeywell.com/honeywell/ProductInfo.aspx/L408J1009]http://customer.honeywell.com/honeywell/ProductInfo.aspx/L408J1009

get the 0-16 not the 0-4 .. and get the break RB on rise version.



i got mine from [url=http://www.patriot-supply.com/]http://www.patriot-supply.com/ (actually I got it from their ebay store.. which seems to list them cheaper http://cgi.ebay.com/HONEYWELL-L408J1009-0-16oz-VAPORSTAT-SPDT-MERCURY-FREE_W0QQitemZ380069168834QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item587de346c2 )

steam-rookie

really, really, old

Is it so old that it might be original?

Did they have vapor-stats 65 years ago

Hello  JP,  I will post the new clear tube results tomorrow. Once I stop the boiler from cutting out under the 0 psi mark, like I said, the cut out pressure is going to change for the worse.

Why would the original designers of this system create a situation that causes the water to rise up higher than the return pipe and enters the main?

steam-rookie

vew settings

I changed the setting on the pressurtrol to prevent the boiler from dropping into negative pressure between cycles. the boiler now cuts back in at 2 oz.

As a result of this the cut off pressure went up to a litle bit over 1 psi

As I expected the water in the clear tube test gauge now rises past the dry return and about half way up that 8" nipple that starts my antler. Way to high.

Please read my last post and let me know what you think.

malp

1 pipe?

You have a 1 pipe system, yes? The system shouldn't build any significant pressure until all the pipes and radiators are full of steam and all the vents are closed. At this point, the system is closed off from the atmosphere. The difference between the boiler pressure and atmospheric pressure does not affect how high the water stacks up in the returns. The only things that affect how high the water stacks are the differences in pressure between different parts of the system due to friction, steam condensing, boiler surging, etc.

steam-rookie

new pictures

System begins to build pressure after all vents are closed and all convectors are full of steam. This is as low as I can set the cut off pressure with the current presurtrol. It cuts out at about 1.3 psi

Mike Kusiak_2

Water rise in plastic tube

Malp has a good point. The water rise in the plastic tube does not indicate that the water level is rising that far in the return. It only indicates the pressure relative to atmospheric pressure, not to the pressure in the return. If you wanted to find the actual water level in the return you would have to connect the open end of your plastic pipe to the top of your return where your vent antler is located. This would equalize the pressure and show the actual level.

malp

deltaP

I'm just saying your tube measures the difference between the pressure at the return and the atmosphere. I don't think that's the pressure drop you're interested in since the system's closed to the atmosphere when everything's hot. Your original problem was squirting vents at the ends of the mains? I'm sorry, I don't know how to fix this. could be too much water in the system due to poor near boiler piping, dirty water, or maybe pipes are too small or uninsulated

Unknown

Question for a Pro

In reading one of jpf's comments this system apparently doesn't have a Hartford Loop.

I don't have my TLAOSH handy but wasn't one of the benefits of the Hartford Loop is that the equalizer pipe eliminated the need for a check valve in the Wet Return?



I guess the question is:  What affect is there to the water level height in the return if the system doesn't have an equalizer pipe?  Is it above the 28 inch (The "A" Dimension) allowance?

- Rod

malp

another thought

The equalizer also returns water in the header back to the boiler. No equalizer means the water instead goes up into the mains, maybe causing the vents to squirt.

Unknown

No Equalizer Pipe

Yes , There's that too! My thought was that without the equalizer pipe the boiler water will back farther out of the boiler. With the equalizer balancing the boiler pressure, all you need the "A" dimension for is to deal with the steam pressure drop.

- Rod

jpf321

a few thoughts

1) malp is right, you should connect the open end of the tube to the vents since you are currently testing against atmospheric pressure rather than internal system pressure.  malp is it possible to simply subtract 14psi for atmosphere or something and convert that to inches?



2) SR builds pressure very quickly since he only has 1-pipe convectors and they hold a very small amount of steam relative to free-standing rads.



3) since you experience no water hammer, i'm puzzled. if the water is stacking up above that last elbow, then it should be backing into the horizontal mains and causing hammer. or at least very slow heat to the last couple of take-offs.



4) i don't think you are stacking back that far or that high since it would require a large volume of your boiler water to fill the mains and if you stacked another 10 or so inches above that last elbow, you would have mains which were completely full all the way back to the boiler

malp

hmmmm......

The definitive way to figure out how high the water is stacking up in the returns is to just run a clear tube from the wet return to the end of the main. I think this is what you're suggesting JP.



Or on further thought:

malp is it possible to simply subtract 14psi for atmosphere or

something and convert that to inches?



Stretching my knowledge here, but you're measuring the gauge pressure at the returns.  You could convert that to absolute pressure by adding 14psi or so, but that wouldn't be a useful number. Switching gears... You know the boiler pressure from the pressure gauge on the boiler. You know the pressure in the return from your manometer. If you subtract the two pressures, you would get the pressure drop across the system. Is this correct? The water in the returns has to pile up enough to overcome this pressure drop?



This is a little speculative. I have a tough time imagining the effect of a missing equalizer. The equalizer (or check valve if equalizer is missing) is there to solve a transient imbalance in the system. After all, if everything were in constant equilibrium, the check valve would always be open or always be closed. Transient imbalances are tough to visualize and even tougher to calculate, and I'm not qualified to speculate on their effect.

steam-rookie

Its getting complicated

The last few posts are getting complicated

Maybe I can simplify a few things

When I first saw the water in the tube go up to the ceiling I thought that it was backing up that far into the return. apparently that is not so

The water level in the sight glass never goes down. It jumps up and down about 1/2" to 3/4" but that's it. I have read that the water in some systems actually leaves the boiler and then returns as condensate. The water never leaves my boiler. If the water never leaves the boiler it cant be backing up in the return??

All of the convectors are hot, quiet, and the house is very comfortably heated.

There is no water hammer in the system and never has been.

Work has been very busy this week, that's why I have been posting so late.

I am off on Sunday

This is what i plan to do:

Change the configuration of the antler to include an extra elbow/with close nipple. This will enable me to achieve additional slope on the antler and hopefully quiet down those G`2s.

Flush out the filthy water.

When I did the plumbing job last week I had to completely drain the system out to change that drain valve. What I noticed was that you can not drain the boiler into the slop sink. There is a lot more water in there. After the hose stops running in the slop sink you have to go to the bucket. those last few buckets of water have most of the dirt in them. When I refilled last week the water in the sight glass was dirtier than it had been before I started. I am sure that I need to give this boiler a good flushing out.

Maybe that will help the G2`s, as previously mentioned.

Let me know if this is a bad idea to flush it out two weeks in a row? I plan  to bring the new water to a boil immediately.

djthx

Flushing your steam boiler

In answer to your last question, as long as you boil any fresh water added to the boiler (to remove the oxygen), you won't get into any trouble by flushing the system.  Have you tried using tri sodium phosphate to clean your system?  I use Scout, and it works great.  Also, have you tried skimming the boiler (in order to remove oil)?  I find that in order to effectively skim your system, you it's best to use a horizontal tap located above the water line.  If you skim from the top of the boiler, then the oil will stick to the underside of the top of the boiler.  Also, make that when you skim the water is cold - (and the oil is on the top surface of the water).  If you skim warm or hot water, then the oil is mixed with the water.



As mentioned previously, the equalizer also returns water in the header back to the boiler. No equalizer may result in wet steam, which may be causing the vents to squirt.  I would consider reconfiguring the near boiler piping, which will probably resolve the leaking valve issue.

malp

ok one hopefully easy thing

Sorry for the confusion. I'm tempted to say when you redo the antler, hook the other end of the tube to the antler, so you can see where the water level is in the returns. My only concern is what effect the steam would have on the tube. Simply put, I don't want you scalded by a steam leak. It's the kinda experiment I'd do standing well away from the boiler with my finger on the breaker that turns off the boiler. Or not do the experiment at all. It's also the kinda experiment I'm not qualified to recommend. especially not at 1am...



Part of the confusion is because you have a non-standard system (no equalizer), so we had to work through how it works.

steam-rookie

Update

I am finally done with work this week. Tomorrow I will be flushing the boiler.

I would love to try the skimming idea. What would be a good horizontal tap to use that is above the water line?

Can I use the little drain specked that is located at the bottom of the sight glass?

I think I could use that scout stuff, This boiler is very dirty.

Do they have it a HD? Are the directions good? Any tips you can give me on the entire flushing procedure? I have never added a chemical to this boiler in 17 years. where does it go if? I hope your not going to say the pressure relief valve on the top of the boiler. It needs to be replaced anyway but looks like its going to be real hard to get off.

I`m not sure how I could attach that clear tube to the antler. I will be taking a look at the various fittings at HD tomorrow. Yes, I will be careful



Today I took some time measurements

From warm pipes, the results were as follows:

6 min. to steam

11 min. to end of main

20 min. to cut out

22.30 min to cut in

25.30 min to cut out

27 50 min to  cut in

30.50 min to cut out

33.15 min to cut in

36.20 min to cut out

38.45 min to cut in

41.40 min. to cut out

I stopped timing at this point

Summery:

It took 6 min. to make steam

It took 5 min. to fill the 100' main  (old main vent took 31 min.)

It took another 9 min. for it to cut out at 1. 2 psi   (used to go over 3 psi)

IT continued to cut in at .25 psi and out at 1.2 psi every 3 min.

it cycles on and off like this an average of about 6 times (has always done this)

The G2`s begin to his at .07 psi

They stop making noise at .25 psi

Its not a real loud hiss but it is audible. It also sounds a little watery, but there is no spiting.  The G2`s do close all the way after the main is hot. But as soon as the system reaches the .05 psi level the hissing starts. It continues until the pressure drops down below .25 psi. the boiler cuts back in again, and the hissing starts again.

djthx

Flushing steam boiler.

You can get Scout at a heating/plumbing supply house (haven't seen it a HD).  The instructions are included and are simple.  The amount you use depends on the the size of your system EDR.  You have to get the stuff into your boiler, you let it run for a few days, and then you then flush and rinse.  If your system is very dirty, you can clean the system more than once.  Just remember to fire your system any time you add fresh water.  



A sure sign of oil in your boiler is moisture in the gauge glass above the water line (it should be bone dry).  And I imagine you can use any horizontal tapping as long as it's located above the water line.



Dan discusses cleaning and skimming - as well as other pertinent steam system issues in "A Steam Heating Primer" [url=http://www.heatinghelp.com/article/11/Hot-Tech-Tips/128/A-Steam-Heating-Primer]http://www.heatinghelp.com/article/11/Hot-Tech-Tips/128/A-Steam-Heating-Primer.  It's an excellent article. 

Mark N

Thermostat

The first thing I would be looking into is why hasn't my thermostat shut down my boiler if the convectors are completely hot.  What kind of tstat do you have and where is it located.  I hope you realize you might not be able to fix your system with your current boiler if it as oversized as it seems to be.  If your boiler is able to completely fill your convectors in 9 mins you have no where near 360 sqft EDR.  It take your boiler 1 hour to make that much steam.



Mark

jpf321

convector EDR

Mark on what are you basing these statements? I went around to all of his convectors with Dan's EDR book and we measured about 295EDR .. please remember that the convectors hold a substantially smaller amount of steam than a regular free standing radiator. He has Governale units as shown on pg 216 of E.D.R. book as well as what we believed to be American Standard Arco Multifin as shown on pg 198.



According to Gill & Pajek paper, convectors hold 0.0003 cf / sf EDR vs radiator which is around .01 cf / sf EDR this difference is HUGE and I believe it to be completely possible to fill the convectors in almost no time. His cf within convectors of 300EDR is only 0.09 total... which is equivalent to a single standing tube rad of only 9sf EDR.



As I mentioned in previous post regarding SR's system, I really don't know enough about how convectors and their miniscule amount of steam volume factors into boiler ratings. If anyone can clairfy how a convector only system correlates to boiler steam ratings and such, I'm happy to learn more.

Mike Kusiak_2

Exactly

Not only is the internal volume of the convectors miniscule compared to standing cast iron radiation, but there is also the issue of their low thermal mass. A house full of cast iron radiators may have to heat thousands of pounds of iron before fully up to temperature, at which time pressure will begin to increase. Conversely, the convector's mass is only a tiny  fraction of that of cast iron radiation, so it will come up to temperature very quickly and therefore build pressure almost immediately.

Mark N

EDR

I think the the EDR has to do with surface area. The surface area determines how much steam you can condense in a given amount of time. I don't have Dan's EDR book as I'm not a heating contractor and really have no need for it. I looked at Gerry Gill's book it states how much air rads and convectors hold. These are used to determine what size vents to use. I took a quick look at the governale web site and it seems that the EDR of a convector can change when you change its height above the floor. Its EDR has changed but its actual surface area hasn't. Then throw in the cabinet and that can change it even more. According to what i've read I can put a cover on my rads that will increase their output 10% but their actual surface area hasn't changed. Or I can use one that decreases their out by 35% and again their actual surface area hasn't changed. I think something like this is going on with these convectors. Let's say they have a real EDR and an effective EDR based upon how they were installed. Finally back to what you asked. Steam rookie's boiler has a net of 360sqft of steam. It takes a certain amount of time to produce that much steam. I think that it takes longer than 9 minutes. Also rads don't hold steam they hold air that needs to be vented. Rads condense steam.



Mark

steam-rookie

convector pictures

This is what my convectors look like.  There is one in each room. A total of eight.  They heat up the house very comfortably.  It is true that once the main is full of steam, the convectors are then filled up, hot, and vents closed in 9 min.

jpf321

originally yes ..

originally yes, the EDR (Equivalent Direct Radiation) was based on surface area .. and I really don't proclaim to understand how convectors play into this .. yes the convector data varies based on cabinet height .. i think in this case EDR is basing used to determine how much/many convectors are needed for a particular heat-loss situation .. and this is also why I was hoping someone had some insight on the other side of the equation, how this correlates with the boiler rating for EDR.



i am only going based on the data in the EDR book and as you saw on the governale website .. they certainly use the term "EDR" .. i think that the part that brings it together is Gill & Pajek showing the miniscule amount of volume (whether steam or air) .. but I still don't know how that really correlates to boiler sizing.



i truly believe that SR is filling his convectors and coming to pressure very very quickly based on a similar house with standing rads (mine for example) .. additionally, as posted here, once the steam goes out, they cool very quickly since they have no CI mass.



jpf

Mike Kusiak_2

EDR

EDR really is a measurement of how much heat a given emitter can dissipate to the surrounding environment under a given set of conditions. In the case of steam the conditions are one sq. ft of EDR will emit 240 BTU/hr at a surface temp of 212F and ambient room temp of 70F. It really does not matter what the ACTUAL surface area is, but rather the EFFECTIVE surface area. No matter what the physical shape, size or construction, If it can emit the same number of BTU/hr under those conditions, then it will have the same EDR.

The difference in internal volume and thermal mass may affect boiler sizing in that although in steady state, convectors and CI radiators of the same EDR rating require the same boiler steam generating capacity, the pickup requirements may be less for the convectors. Since they fill with steam and heat quicker, you might not actually require the full 1.33 Pickup and Piping oversizing factor.

Mark N

Convectors

JPF do you recall what the rating is of the convector that SR just posted a picture of?  Since I don't have the EDR book how does the book explain how to size it?  Since I don't size boilers for a living I think we need Steamhead or Gorto or Gerry Gill or possibly Dan H. to explain if the process of sizing a boiler is different with convectors than it is with cast iron rads.  Do convectors actually have a surface area that is different from their EDR rating? 



Mark