Determining EDR on a radiator.

SteamingatMohawk

I bought Dan's EDR book that has a couple hundred pages of radiators, convectors, etc.

I am trying Gerry Pajek's calculations and need the EDRs for my radiators.

The problem is none of the radiators in the book match what I have. The main difference is the width of a section is actually 1.75" and there is no bushing visible. The other actuals are a bit different for similar units, but it may help with better guessing.

Does anyone have any suggestions on what to use?

I tried to find some sections that are close, but comparing a couple of radiators leads to as much as a 40+% difference in the EDR.

So, the main question is about how to find better actual data and/or make a feeble attempt at educated guesses. And of course, depending on the system, how much difference it makes in the calculations, if any is a reasonable question.

There are slenderized Burnham radiators on pages 190-192. and look like the Gothic (93 - 96) or Capitol (136 - 142) radiators in the book

Here's the table.

bburd

If you post some pictures, we may be able to help identify your radiators. There is a book called "EDR:  Every Darn Radiator" that some folks here have on the shelf.

EBEBRATT-Ed

He has the book.

@SteamingatMohawk You may just have to find rads as close as you can get and use that.

How old is the building? As time went on most rads were a standard size early 1900 not so much.

bburd

EBEBRATT-Ed said:

He has the book.  

Oh.

Never mind...

SteamingatMohawk

The house is near Schenectady, NY and was built in the late 1920s. 

SteamingatMohawk

This is the end of the hallway radiator. Sorry for it being rotated...

1 tie rod near the top, 2 near the bottom

BobC

Thats a tuve stile radiator and it looks similar to the imag one the Smithfield EDR sheet,

It has 4 tubes and looks tro be 26(?)" tall so it would have about 2.75 EDR per section. Not all of these are built the same so there will be some variations on a theme. With EDR you don't have to be exact, a little iver or under won't really matter

SteamingatMohawk

The actual has straight legs and 1 tie rod at the bottom. The length for 10 sections is 25 inches vs actual around 17.5. 9 bushings at 0.5" takes it to 23". Pretty close. Heights are pretty close.

SteamingatMohawk

SteamingatMohawk

Close enough?

EBEBRATT-Ed

@SteamingatMohawk

I have some radiation books. I will take a look.

Steamhead

That's a small-tube rad. In "E.D.R.", look at the Burnham Slenderized chart (1939).

EBEBRATT-Ed

The rads you are looking at from Dans book are HB Smith. I have a Smith book and a Weil Mclain book but they don't match your rads.



BEDROOM 1 7 section 17 1/2" long x21" high x 4 5/8 wide=10.5 sq feet 3 TUBE

BEDROOM 3 same 10.5 sq feet 3 TUBE

Hall 10 section 25" long x 21 high x 4 5/8 wide= 15 sq feet 3 TUBE

LR 1 12 SECTION 30" LONG X 21" HIGH X 8" WIDE 30 SQUARE FEET 5 TUBE

LR 2 10 SECTION 25" X 21" HIGH X8" WIDE 25 SQUARE FEET 5 TUBE


What I did is ignore the number of tubes. I took your rads length x width x height and picked the rads that are the closest to your overall dimensions.

Since the overall dimensions are about the same the rads will probably pretty close in weight...same amount of metal and should be close enough

SteamingatMohawk

@Steamhead The Burnham slenderized is pretty darn close. The length of a section is 1-1/2 +bushing and mine are 1-3/4, without a bushing...close enough for me. The 6 tube is about an inch narrower than mine, but seeing that the rest is so close, I'm going to go with that radiator design.

Thanks, everyone for your assistance.

I started this journey several years ago and was going to try to use simultaneous equations, but found there are too many variables and I didn't think I would get the equations right anyhow.

So, I calculated like Gerry did, got numbers without taking into account the radiators and let it be.

Now I'm trying to get a better feel for reality based on Gerry's method.

One thing I think I messed up is that the radiator in the coldest room (which also has the lone thermostat) has a Heat Timer full open, venting multiple times faster than the other radiators. I think I mistakenly did that because I thought it would be better to have that radiator vented quicker than the others...bad idea??

Since for the last 4 years, no tenants have complained I'm not in that much of a hurry to change it...except in the last pages of Gerry's report there is a section on overventing with a Heat Timer as the culprit. He says they can vent so fast that it is possible to draw a vacuum into the piping, potentially starving other radiators for steam..

Let me ask one final question for now? Should I calculate based on 1, 2 or 3 oz pressure?

EBEBRATT-Ed

1/4 psi would be 4 ounces.i wold go by the average pressur you run at. You could stick a gauge on a rad and see

Steamhead

@SteamingatMohawk , I usually calculate main vents at 1 ounce and radiator vents at 3 ounces. This ensures that the mains fill with steam first.

SteamingatMohawk

Phew, no one said to do all three pressures!  

SteamingatMohawk

@Steamhead I like your logic.

SteamingatMohawk

Has anyone ever noticed the inconsistency in the Gill/Pajek report about the Vent Rite #1 1 oz. venting capacity. Setting 2 is higher than setting 3. See below

SteamingatMohawk

@Steamhead I'm about at the end of my calculations. Just one question. In the Gill/Pajek report Gerry uses 3 minutes for venting the radiators. In the report he says he likes to vent quickly. He doesn't talk about the mains. One of the concepts I have come across on HH says to vent the mains quickly and the radiators slowly.

Assuming I didn't mess up my calculations, both mains have G#1s at the boiler end of the main. Using that capacity and 1 oz. pressure yields 2.3 minutes front and 1.1 minutes rear. I also have a G#2 on the front main which reduces the vent time for the front to .54 minutes. That's plenty fast for me either way. I could substitute a second G#1 for the G#2 and that would yield 1.2 minutes, essentially the same at the rear main. I have a spare new G#1 I could substitute. But, going back several years with no complaints, why....

Back to the original question for everyone, what is a reasonable venting time to use, Gerry's 3 minutes, something faster or something slower?

I'm not sure it is coincidental or not, but when I did the 1oz pressure with 3 minutes calculation for a tube radiator (0.013 conversion factor) there are 3 MOMs in the house that vent between 2.7 and 3 minutes by the calculations. The other radiator vents are VR#1s which are set to a lower vent rate, because of how those rooms heat up.

That last statement is consistent with the comments in the Gill/Pajek report that the calculations are a starting point, not the be all, end all.

KC_Jones

With main vents you are starting, and preferably ending at or very close to zero pressure, so you are going a good bit slower than the 1 ounce rating. I have a 25' main with 3 Gorton #1 vents and the fastest I've ever seen on that is about 2.5 minutes. According to their chart I should be able to vent that main in ~1.6 minutes with a single vent. So that shows how the charts are just a guide for relative speed, not what you can expect.

To get even the 1 ounce venting rate you'd need to hold the steam back, build up to 1 ounce, then release the steam and hope it stays at 1 ounce, which it most likely won't.

SteamingatMohawk

I understand and agree and realize that on initial startup the piping is "cold iron" and the actual venting will be slower because of the heat removed to warm the main.

I have never timed the venting from an already "hot" system.

I could calculate how much steam energy is needed to warm up the pipe and see how that compares to the venting rate. That calculation gets more complicated because of the energy absorbed by the insulation on the supply part of the main and the heat loss on the uninsulated portion of the return side.

As far as the type of radiator, I went back and looked at previous comments. One said they are tube radiators. The other point is the table on p. 24 of Greening Steam for column radiators only goes to 4 columns. Some of my radiators have 6. What caused the disconnect is that in multiple places there are conversion factors for column and tube, but the column is "circa 1900" and tube is "circa 1930". My building was constructed in the 1920s, so I wasn't totally sure which conversion factor to use. With enough searching, looking a sketches and calculating, I satisfied myself they are tube radiators.

And like "magic" the calculations are pretty close to the MOMs with #5 and #6 orifices.

Science triumphs again.

Steamhead

SteamingatMohawk said:

As far as the type of radiator, I went back and looked at previous comments. One said they are tube radiators. The other point is the table on p. 24 of Greening Steam for column radiators only goes to 4 columns. Some of my radiators have 6. What caused the disconnect is that in multiple places there are conversion factors for column and tube, but the column is "circa 1900" and tube is "circa 1930". My building was constructed in the 1920s, so I wasn't totally sure which conversion factor to use. With enough searching, looking a sketches and calculating, I satisfied myself they are tube radiators.

And like "magic" the calculations are pretty close to the MOMs with #5 and #6 orifices.

Science triumphs again.

Tube radiators with section spacings of 2-1/2" are known as "large-tube" radiators, and were made between 1925 and 1938 or so. After that they were basically shrunk into "small-tube" radiators, with section spacings of 1-1/2" or 1-3/4". These are still made today.

SteamingatMohawk

Thanks for the info. When I asked about pressures to use, I did not specifically mention venting times. What is your advice for times?