Trying to identify and rate this convector

D107

Mid 50s, cabinet 36 in L, 24in H, element 2inH x 5.5inD. 6-7fins per inch. Seems to be three tubes inside. Put a magnet to the fins, no reaction, so I'm thinking aluminum? Trying to get btu rating at 180deg.F. I'm thinking around 4000? Can't find this in Dan's book, anyone recognize it?

Charlie from wmass

try this page

it is in Dan's library under resources, then American Standard Productshttp://www.heatinghelp.com/files/articles/928/299.pdf

appears to be 35.4 square feet of radiation. Roughly 6000 btu's

D107

Thanks

Thanks for digging that out. Seems very similar except for the air vent assembly if you look close up, and heat output grills which are shorter on our convectors, but the measurements seem right on. Don't know if the EDR is constant whether steam or HW. Apparently you mulitplied the EDR by 180 and got the 6000+ number. Doesn't say copper so I'll assume aluminum if they were making them in the 50s. Thanks again.

Mark Eatherton

Pipes are copper...

Fins are aluminum.



The EDR for hot water is 150 per square foot. The 180 assumes steam.



If that is an old Trane convector, attempting to convert it to hot water will cause it to sing due to restrictive orifice in the return.



ME

D107

HW

Thanks Mark, system is and will remain HW. I guess they use 150 as an average water temp --160 supply, 140 return(?)--not always easy to compare apples to apples with various manufacturers emitter ratings. some don't give EDR, just btu/hr at 180, 190, etc.

Mark Eatherton

Yes, and no...

The EDR is Equivalent Developed Radiation, which is expressed in square feet of heat emitting area. When using hot water, with an average temperature across the emitter of 180 degree F water, then each square foot of EDR will emit 150 btu/sq ft/hr.



When used with steam at around 212 to 215 F, that EDR output number jumps to the 180 btu/hr/sq ft.



Didn't want you to be confused. Average fluid (yes, steam is considered a fluid) temperature and EDR output have some similar numbers, but mean different things.



If the convector WAS originally a Trane steam system, they had a 1/4" restrictive orifice in the outlet, that when you force water past it, causes it to whistle (Thanks Frank) like a train (Trane?)



ME.

D107

Great explanation

Thanks alot.

Charlie from wmass

to befuddling things a bit

Mark my charts have 240 btu's per square fot for steam and 170 btu's for 180 degree hot water. If it had been used for steam and you are converting it to hot water make sure it has been well tested for corrosion ans for restrictors as Mark stated.

Mark Eatherton

Opppss...

Charlie is correct. I have WAY too many numbers bouncing around in my head, and am getting too old to be trying to recollect from memory...



http://en.wikipedia.org/wiki/Equivalence_of_direct_radiation



Thanks for the catch Charlie.



ME

gennady

ratings

Burnham heating helper http://www.scribd.com/doc/27425454/Burnham-Heating-Helper-Table-of-Contents on pages 20,23 has a great table showing correlation between EDR, Btu and temperatures of radiators. very simple and handy.

D107

De-rating from being recessed

Then of course the EDR ratings probably don't take into account fully or partially recessed units. Or do they? Mine is 2/3 recessed. Back metal wall of cabinet is probably right up against the 3/4in sheathing. Got to be at least a 20% loss from that, eh? Seems like convectors and cousin baseboard inherently require relative short-cycling; give me cast iron any day.

Charlie from wmass

No problem Mark

Thats why we all have bookshelves, they keep track of things better then we do. c

p.s. I double checked before I said anything incase I was wrong.