Output of finned tube in \"window box\"

Bob Vennerbeck

but the description rang a bell and I was reminded of how I finally identified mine - the online literature I pointed to includes photos, scaled drawings, output charts and installation notes - all of which helped educate me about similar items. Gotta start somewhere, and I thought I could help.

Gordan

Hi,

My house has an old (1951) diverter tee system with finned tube enclosed in under-window convection boxes. The boxes have a cut-out in the baseboard at the bottom, where cold air goes in, and a grille near the top, where it comes out. The emitter is "insulated" from the outside by 3/4" of fiberboard (looks homasote-ish) on top of 4" solid masonry block, topped by an inch of stucco. How would I even start to go about estimating the output of one of these beasts? (I realize that measuring flow and delta T across the emitter would give me the output, but cutting into the pipe is not an option.)

Many thanks,

Gordan

Unknown

Gordan

Can you post a pic with the front cover removed & we`ll see what we can do?

Dave

Gordan

I will certainly do that and post it this evening. Thanks!

Bob Vennerbeck

convector output

These sound just like the Beacon Morris convectors that I picked up at a barn sale 30 years ago - and if so, the data is all still available online:

http://www.beacon-morris.com/html/forced_hot_water_steam_heat.asp

If not an exact match, probably good enough to estimate from.

Good luck!

Vbob

billtwocase

wall convectors

that's what it sounds like on a monoflow system?

Unknown

Just curious Bob Vennerbeck,

without a pic, how would you know that?
Please don`t tell me "they`re all the same" hmmm.

Dave

Unknown

1951?

Are you saying 1951 is OLD? Many people do wished they have the 'old' system, with a new boiler, of course for the comfort.

billtwocase

old

I have all cast iron baseboard in my home, and wouldn't replace it with anything but. peace

bob young

MAKES good sense to me, bro

Dave Stroman

Why do you need to know the heat output? Are you having problems?

Dave Stroman

bob young

maybe sizing a new boiler

Dave Stroman

That is not the way you size a boiler.

Dave Stroman

bob young

new manufacturer

maybe he is starting his own fin tube radiation factory and he is preparing a three color brochure'

Gordan

Yep, that's what they are.

Gordan

Nope, these are custom built.

It's a very similar concept to the fully recessed ones, but everything was site-built. I have the pics with measurements but couldn't find my camera's USB cable. I'll upload tonight.

Gordan

I'm evaluating how much I would have to change out if I replace the heat source. Knowing the emitter output is one of the variables. It may not help me size the boiler, but it should help with choosing between condensing and non, as well as the control strategy.

Gordan

The big picture...

Sorry about the size. The fin tube element is 5.75" deep by 2.5" high by 29" long. The baseboard cutout is 32" wide by 3.5" high. The grille (the actual inner grid part, not the flange) is 5.25" high by 31.5" wide, and located 19" above the floor.

Charlie from wmass

So I am guessing you are doing a heat loss for the home and then seeing if the emmitters were as over sized as the original boiler. If this is the case then a condensing boiler would work well as the water temp could be dropped with an outdoor reset to match the load. If on the other hand the emmitters need 160 F or hotter water to warm the rooms then you will just go with a conventional boiler around 86% AFUE.

Charlie from wmass

Gordon my thoughts are that the units had factory covers at one point and were refitted with these as the grilles look far newer than the then the emmitters. the beacon morris charts should get you close but I would figure a lower output for a given size as the original openings are not known.

Gordan

Charlie,

Thanks! The enclosures were actually custom built from scratch on site, but the finned tube elements do look a lot like the Beacon Morris ones. The specs in that PDF don't even go below 160 F supply temperature. Is there any way to extrapolate convector output for lower supply temps?

M grallert

Mr. H's book Every Darn Radiator will have it and the outputs, and it's a cool book to have.
Peace
Matthew

Gordan

Scratch that...

Looks like it's proportional to delta T, so for every 10 degrees of supply temp drop I would lose 20 BTU per sqft of steam EDR.

Which means that the output at 140 degrees supply would be half of the output at 180 degrees supply (based on a 10 degree drop across the emitter.)

Anyway, thanks, all!