Sq ft of steam:sq ft of EDR

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826157#Comment_1826157

No, but it's never too late to improve so keep trying.

AndythePlumber

I just want to thank everyone for their input and knowledge. The question-at least to me-has been handsomely answered. The church I’m quoting measures at 970 sq ft edr. We have a hybrid system

One pipe on the first/second floor radiators, and the basement has 2 pipe baseboard. The baseboard we have deduced was added to the system and while doing so destroyed the a dimension, necessitating a feed pump. We are going to abandon the baseboard. This will take it back to a true one pipe gravity system. Mooting that pump. Simplify all that happy crappy. Then we are going to install a hot water boiler for the baseboard. Two separate-simpler systems.

970sq ft edr.—current boiler has 2700sq ft steam rating. We can do much better. The previous contractor clearly used the “door” method for sizing

Thanks all

ethicalpaul

You can easily run hot water from the steam boiler through the baseboard

AndythePlumber

https://forum.heatinghelp.com/discussion/comment/1826049#Comment_1826049

970sq ft

ethicalpaul

Peerless 64-08. And it will have enough left over to run your hot water loop and the tappings to make it super easy

saias

I've been trying to understand this. For something that seems like simple math, I find the available information to be confusing/misleading. If I'm reading things correctly from the Peerless specs, the steam sq ft rating includes the 1.33 pickup factor.

"Steam ratings are based on a piping and pickup factor of 1.33."

I get there are good arguments for and against 1.33, but I don't want to get into that debate.

So, is the 996 sq ft rating on the 64-08 actually 749 sq ft when you take out the pickup factor?

My EDR is 332 sq ft, but a radiator was removed at some point by a previous owner that I would like to reinstall. This will likely take the system to 360 sq ft. Would the Peerless 63-04L rated at 383 sq ft be ok? My current boiler is rated at 479 sq ft.

ethicalpaul

Yes it would be plenty

So, is the 996 sq ft rating on the 64-08 actually 749 sq ft when you take out the pickup factor?

No, the opposite. The boiler is actually larger than that rating

LRCCBJ

So, is the 996 sq ft rating on the 64-08 actually 749 sq ft when you take out the pickup factor?

My EDR is 332 sq ft, but a radiator was removed at some point by a previous owner that I would like to reinstall. This will likely take the system to 360 sq ft. Would the Peerless 63-04L rated at 383 sq ft be ok? My current boiler is rated at 479 sq ft.

Paul posted an excellent chart for the Peerless 64 above.

Take a look at "gross output" for the 64-08. You will see 318 for steam. This is the output after the combustion efficiency is included in the data. You lose 81 KBTU out the chimney.

Now look at the "net ratings" for steam. You will see 239. The manufacturer assumes that you will need 33% additional capacity so they rate the boiler at only 239 KBTU despite the fact that its output is actually 318. The 33% reduction has been a bone of contention around here for years.

If it were me, I'd use the 63-03. 98 KBTU yields 408 sq ft. You'd have a pickup factor of 48 sq.ft (360 EDR)…………..12%. Plenty if you insulate the piping and install it per the manual. It will never cycle on pressure.

saias

https://forum.heatinghelp.com/discussion/comment/1826206#Comment_1826206

That seems counter to what Peerless and other manufacturers say on the spec sheets. Maybe it's just poorly worded. The Peerless footnote ("Steam ratings are based on a piping and pickup factor of 1.33") is not clear. If what you say is true, why don't they say something like "Steam ratings are based on the connected radiator EDR and does not account for any pickup factor."? Not a question for you, but for Peerless marketing.

KC_Jones

https://forum.heatinghelp.com/discussion/comment/1826260#Comment_1826260

Your statement makes no sense. The boiler rating in sq ft accounts for the pickup factor. So adding in:

"Steam ratings are based on the connected radiator EDR and does not account for any pickup factor." would be a factually incorrect statement.

ethicalpaul

Yeah I think the existing wording is fine, but regardless, this is why it's just good to look at net sq ft of steam vs EDR, so you don't have to be confused by all this net/gross btu stuff. Allow them to make things easy for you.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826264#Comment_1826264

Personally, I look at the gross output spec and do my own math.

For most who are confused by this stuff, I'd say go by the steam EDR spec of the boiler and don't add anything to your number and try to get the boiler number as close to the radiation as possible. Preferably being slightly under on the boiler side. If the boiler says it can do 325sqft and you've got 300-350 I'd call that good. If the boiler says it'll do 325 and you've got 250, even 280 I'd say no dice, go down a size.

LRCCBJ

("Steam ratings are based on a piping and pickup factor of 1.33")

"Steam ratings are based on a piping and pickup factor of 1.33, so we divided our net output by 1.33 to reflect this reduction in the capability of the boiler"

Feel better now?😀

I'll let Peerless know. I'm sure they will change it instantly.

dabrakeman

Having spent my entire career sizing systems, not steam heating systems but rather automotive braking systems I think Jamie's statement :

"And of course that is the least predictable variable of the whole lot! What are the expectations of the end user?"

,hits the nail on the head. A home or business HVAC system is like a brake system, a safety system first and foremost. Therefore, rules have been developed for the near worst case user/application. You as the designer do not know whether the end user is Mario Andretti living at the top of a mountain or granny living in Nebraska. Maybe the next owner of that old house is also granny who needs the home at 80F and doesn't have the money or wherewithal to fix all those leaks and drafts in the house. Certainly the advantage of heating is that each application does have the opportunity for individual evaluation and in most cases the "rules" can be bent quite drastically, however, not convinced that is justification to change the rules defining the starting point though.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826278#Comment_1826278

Minor issues in a braking system like a balancing problem could kill people. I might even say are likely to kill people. Airplanes are a similar situation, minor problems could kill.

As long as a few radiators heat in a home, usually it won't have a life and death situation, no?

I think braking systems in vehicles are far more critical. I'd also like to talk to you about them in PM if you ever have time.

dabrakeman

Happy to

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1826281#Comment_1826281

Hmmm. Well, I agree that adequate (or better!) braking systems in a vehicle are a more obvious problem. However, as our friends the Brits across the pond are finding out the hard way, inadequate heating systems — or the inability to pay for heat — do, in fact, kill people. The current flap is over a fuel subsidy, and there is a rumbling ongoing roar over forced conversion to heat pumps, but the figure buried in the uproar is that inadequate heat for whatever reason is a factor, and sometimes the only factor, behind excess death rates among older people of around 10% (that is to say, around 10% of the over 80s who die in any given year probably wouldn't have, had they had adequate heat). Something to ponder.

saias

https://forum.heatinghelp.com/discussion/comment/1826262#Comment_1826262

That's what I thought, but I was thrown off by Paul's response that the boiler is larger than the rating.

I had in my head to size the EDR as close to my radiator sq ft calculation and go slightly under if possible just as ChrisJ said.

Appreciate the responses to my overthinking this.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826292#Comment_1826292

Overthinking it is much better than not thinking about it.
It's best to get it right.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826290#Comment_1826290

Not being able to pay for heat is very different from what would happen if a steam boiler was slightly undersized, or even grossly undersized, no?

I'm thinking of all of the houses that have been heated by a single woodstove for centuries.

ethicalpaul

That's what I thought, but I was thrown off by Paul's response that the boiler is larger than the rating.

Isn't it? I'm referring to the boiler's Net Sq. Feet of Steam rating

KC_Jones

https://forum.heatinghelp.com/discussion/comment/1826300#Comment_1826300

Maybe if we show all the math for the 63-08 it will make sense to everyone. So the gross output of the boiler (318000) is higher than the actual rating they give to it (239000). The actual rating is what is matched up to the radiation square footage (996).

Input	399000
Efficiency	80%
Gross Output	318000
Pickup	33%
Net Output	239000
Net Output SQFT	996
Pickup	79000
Pickup SQFT	329

delcrossv

https://forum.heatinghelp.com/discussion/comment/1826302#Comment_1826302

So, to put an end to the confusion, sizing to listed sq.ft. will INCLUDE a 33% pickup?

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1826304#Comment_1826304

Every boiler manufacturer's STEAM EDR/SQFT spec includes the 33%.

If it says it's good for 300SQFT, that includes the 33%. If you want to go by the book, if you have 300sqft, you find a boiler that says 300sqft.

saias

https://forum.heatinghelp.com/discussion/comment/1826304#Comment_1826304

My takeaway is the listed sq ft accounts for the 33%. The number does not actually include the 33% which is why you can match the boiler sq ft to your actual sq ft.

ethicalpaul

He said "sizing to listed sq ft will include…" not that the number includes it. We are really splitting hairs here.

Jamie Hall

What is it Eliza Doolittle sang? "Words! words! I'm so sick of words! I get words all day through…"

It's entirely a matter of clearly understanding the definitions of the various terms… and using them consistently.