Help Calculating EDR

TomH42

My boiler builds way too much pressure for the system. I would like to calculate the EDR of my 6 radiator system. The system used to have 8 radiators (which I understand from Dan's book may adjust the load factor from 1.33 to 1.5) .



There are five fin tube radiators on the first floor and one large iron radiator on the second floor (which according to another article here does not make for harmony).



The current fin tube radiators were made by a company in Rome NY (about 12 miles from where I grew up), I have attached a photo of the label.



The 5 fin tube look like the first photo. The upstairs radiator is photo two.



The dimensions of the fin tube units are as follows:



<strong>Fins are 5" wide and 2" deep</strong>



36" This one is a two pipe unit

18"

36"

30"



<strong>Fins 7" wide by 2" deep</strong>



48"



<strong>Upstairs Radiator</strong>



24" tall



The other five radiators are 1 pipe units.



I would really appreciate it if someone could provide either how to calculate EDR of these specific radiators or just provide the EDR for the system that would be much appreciated.



BTW, the boiler is Dunkirk BS1AAN000150AAAAA. I have attached the info sheet for additional data.

Rod

Calculating EDR

Hi Tom- Attached is a pdf sheet which will help you calculate your radiators' EDR.

- Rod

Alan (California Radiant) Forbes

Need more infor

Dan Holohan's most excellent book, "EDR" lists Rome-Turney Radiator Co., Rocop Convectors, Ratings for convectors with top (vs. face) outlets.  To size them properly, they want three dimensions:



1) Element depth (3-1/2", 5-1/2", 7-1/2", etc.)

2) Element length (18", 22", 26' up to 72")

3) Enclosure height: 16", 20", 23" 26", 29", 32" 36", 48", 60"



And on the upstairs radiator, I see that it has 30 sections, but can't see how many columns there are on the sections, something like 2, 3, 4, 5 or 6.



We'll need this information to determine the EDR.

TomH42

There are five columns

on the upstairs radiator. How do I tell the distinguish between top and face outlets on first floor units? I will get enclosure heights and be post them later tonight.



Thanks to all for info this far.

TomH42

The height

of the enclosure opening for the 5 downstairs radiators is 22" in height.

Hap_Hazzard

Who made the radiator?

Thin-tube radiators are pretty similar, but there are differences, so we might as well get the right values while we're at it.



Top vs. face refers to where the convector housing opens at the top. Recessed units usually have louvered slots on the face while free-standing units often have a grille on top.

Alan (California Radiant) Forbes

EDR ratings

Rocop Convectors - 23" enclosure height

5-1/2 x 2 x 18 - 18 EDR

5-1/2 x 2 x 30 - 33-1/4 EDR

5-1/2 x 2 x 36 - 40-3/4 EDR x 2 convectors



7-1/2 x 2 x 48 = 77 EDR



Gothic 5-column radiator

30 sections, 23" high - 90 EDR



The upstairs radiator might be something other than Gothic (i.e. a Cameo), but the ratings are the same.

TomH42

We're making progress

Thanks for the radiator data Alan.



So, if I am doing this correctly, the total EDR for the radiators is 299.75 (rounding to 300).

We then multiply that number by 1.5 (two radiators have been removed) which provides an EDR for pipes and radiators of 450.



Looking at the boiler manual, the net rating is 383. If we then multiply that by the 1.5 we get a rating of 574.



If I am calculating correctly, (anyone please stop me if I missed a step or screwed this up), my question is;



Is a boiler that is rated at 574 and is heating a system that can deliver a max of 450 too big?



If so, can one burner be removed (I think that is called down firing or down rating) to slow the amount of heat generated by the boiler?



The reason I ask is because



1. Pressure builds on this system pretty rapidly.

2. The air vents work quite a bit on the first floor, like a whistling convention.

3. The unit has really short cycles which does not allow the iron radiator on the top floor to generate heat.

4. Our gas bill makes me cringe each month of the winter.



As always, thanks to everyone of you that help set me and my system straight.

Alan (California Radiant) Forbes

You don't want to

multiply your boiler's net rating by 1.5.



The symptoms you talk about makes me think that either you have no main vents or that they aren't functioning properly. Please check them and get back to us. Your radiator vents are working too hard. What about the upstairs radiator? Is any air coming out of it's vent?



Check your pressuretrol as well. What is it set at?

Steamhead

That's not a column-type radiator

it's a small-tube type. Ratings on these units were pretty well standardized, though I think that one might be an ARCO.



A 5-tube radiator of this type, 23-inches high and having 30 sections is rated 63 square feet EDR. Be certain of its height- if it's actually 25 inches, it would be 72 square feet.

Paul48

EDR

You don't want to multiply the total EDR by 1.5 either.

TomH42

OK, let's scrap 1.5

factor completely. How do I factor the load for piping?



Also, I have included a side view photo of the radiator for determining EDR. It is 23" tall.



I have also included photo of main vents. Bought the Gorton two years ago. To be honest I never hear air escaping it. The other vent does whistle from time to time but that is connected to the return of the two piped radiator. How do I check the Gorton to make sure it is working?



Recently cleaned all the radiator vents. Air does come out of upstairs vent (unit heats up great when boiler runs for more than 2 minutes).



Pressuretrol was recently cleaned as was pigtail with white dial set at 1 and outside reading at .5. That said, last night the gauge indicated it shut down at 5 psi and resumed at 3.5 psi.



Thanks to all for helping with this.

Alan (California Radiant) Forbes

OK then..........

It's a tube type.  But it's 6 tubes, not 5 tubes, no?  And it looks like a Smith "144" style radiator.  The EDR for a 21", 30 section radiator is 90 and for a 25" radiator is 112-1/2.



As far as your pressuretrol, you might need a new one since your system is running much higher than the setpoints.  Check the pigtail again and while you have the pigtail off, make sure the outlet for the pigtail into the boiler is free of debris.

TomH42

Yes, that would be 6

Gotta get my eyes checked. So the EDR does not change from the origial calculations.



I will check the pigtail again.



Any way to check and see if Gorton is working?



Thanks.

Alan (California Radiant) Forbes

Testing a main vent

I would think you could take it off and blow through it. If it doesn't blow, let it go.



Or you could switch the two and see if the Gorton vents.

TomH42

Took it off

and the vent worked most of the time when blowing through it. When keeping the orientation the same, (valve at the top of vent), I was able to blow through it 75% of time. For some reason from time to time the air would not go through.



The vent does sound like a cow bell when I moved it from boiler space to work area.



Next move will be to switch the two vents.

Rod

Boiler Ratings

Hi Tom- I just posted this pdf in another answer and thought it might be of help to you also.

http://www.heatinghelp.com/files/posts/16104/Sizing%20a%20replacement%20Steam%20Boiler&%20Boiler%20Rating%20Charts.pdf

-Rod

TomH42

That is

helpful Rod. Will do calculations shortly.

TomH42

Do these numbers look Accurate?

Thanks again to everyone for help on this. Here are the calculations using all three formulas Ron sent.



Given that I have a hard time counting to 6 as was pointed out earlier, if any of these calculations are in error, I am open to correction. I have also added a photo of the chart for the boiler. Also, I am using a EDR of 90 for the upstairs radiator which may be in question.



Method #1

1. 300 EDR X 1.33 = 399 (do you multiply by 1.33 in this calculation?)

Boiler NET IBR = 383

This suggests boiler is slightly smaller than needed (unless you do not factor load, then it is bigger).



Method #2

2. 300 EDR X 240 = Btuh Load 72,000 (not sure if we multiply 1.33, if so number grows to 95,760)

Net IBR for steam = 92,000 Btuh

This would suggest the boiler is larger than need if we do not multiply 1.33 load. If we factor 1.33, the boiler is slightly smaller than needed.



Method #3

3. 300 EDR X 240 X 1.33 =95,760

D.O.E. Heating capacity is 122,000 Btuh (Input 150,000)

This suggests the boiler oversized by 27%.



All 3 of these calculations cannot be accurate. My guess is the last one seems most reliable but I leave that to the experts.



Is the Boiler too big or not?



Thanks

Paul48

Pickup Factor

It is applied on the other end to get the net.You might want to consider putting some of the radiation back, the boiler is 25%+ over-sized . http://www.masterplumbers.com/plumbviews/2002/boilerratings2.asp

Rod

Using the Boiler Rating Tables

Hi Tom - Like I mentioned in my earlier post, the rating tables can be a bit confusing when you first work with them.

The I=B=R Net Ratings have the “pick up factor” already calculated in so it is only on the third method (#3) that you use the 1.33 multiplier. I've calculated them out below and as you can see they all show a 27+ % oversize.

- Rod



Here are the calculations

Method #1 The NET IBR rating has the

“pickup factor” (1.33) already included so it is a direct

comparison of your radiators total calculated EDR to the Net I=B=R

square foot radiation rating.

Method #1:

Your radiator's Total EDR= 300 square feet.

Your Boiler's NET Square foot rating (from the table) = 383 sq. ft.

Boiler is 27.6 % oversize



Method #2 uses the Net IBR rating in BTUs and also being the “IBR Net Rating” already has the 1.33 pickup factor” included.



Method #2 Converting EDR to BTUs

Your radiator's Total EDR = 300 square feet.

Total EDR multiplied by the conversion factor for steam (240) = Total EDR in BTUs

300 x 240 = 72000 BTUs

Your Radiator's Total EDR in BTUs = 72,000 BTU or 72 MBH

Your Boiler's NET I=B=R rating in MBH (Thousand BTUs per Hour-from the table) = 92 MBH



Boiler is 27.7 % oversize



Method #3 is as per your calculations

“ 300 EDR X 240 X 1.33 =95,760

D.O.E. Heating

capacity is 122,000 Btuh (Input 150,000)

This suggests the boiler

oversized by 27%.”