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EDR question ?

clammy Member Posts: 2,981
I am doing a survey on a steam system which is mostlyall original  wall convectors except a few which where changed out over the years for god knows waht reasons .They are all 2 pipe convectors with no pervisions for air vents ,opper tube steel fin .The promblem i am having is finding these type of cabinet listed they are flsh mounted using screws instead of the standard slip down with rounded edges.They also have a knob with a small damper which is not the whole abinet length.I have Dan's edr book except i an't find anything simalar and i have looked through all of the edr booklets that i have collected over the years .Is there a standard rating i can use to put me in the ball park and i know that the hieght of the cabinet does effect the output but unless i go back and recheck to see if i missed some thing or if i can find a manafactures marking to ID them i am a little stuck .The boiler that is there does heat up quick and then short cycles but it is hard to fiqure weather it is due to over sizing or due to other issues like bad near boiler piping and hi pressure(needs vaporstat)so it kinda of makes it a little hard to determine whih it is piping ,pressure or no oricifes in some changed out raditors .With the infromation that i have collected from my resources it may seem the boiler is not really that oversized but the curve ball is that another company has looked at the system and quoted a much smaller boiler .I am suspect being they left the boiler operating with a clogged pressretroll running hi pressure but did change the main vents which ended up getting wasted in a few days due to water hammer from the high pressure and water stacking in the returns .They did not come back to correct but still sent a quote .Any i hate to say rule of thumb for wall convectors would help .peace and good luck clammy
R.A. Calmbacher L.L.C. HVAC
NJ Master HVAC Lic.
Mahwah, NJ
Specializing in steam and hydronic heating


  • Dave in QCA
    Dave in QCA Member Posts: 1,777
    Recessed Convector

    Convectors were generally manufactured in three configurations.  There is the common free standing type, then the semi recessed, in which it is partially recessed into the wall, and the cover also projects.  Then there is the Recessed type.  It sounds like that is what you have. 

    In the EDR book by Dan, I find examples for fully Recessed convectors on pg. 196-199, 204-206, 211-212, 219-220, 227-228, 230, 233, 244-246, 257.

    The critical measurements are the depth, width of the coil and the height of the enclosure.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • Brad White
    Brad White Member Posts: 2,393
    Also see if

    they indeed are aluminum fins on copper tubes. Some had steel fins and if you are lucky, could be cast iron convectors. The capacities will vary.

    Just one of those details I myself have been guilty of over-looking. A dirty AL-CU element looks like steel but a magnet will tell. Cast iron feels like, well, cast iron and you know that.

    But overall as Dave said, the ratings if you know the element dimensions, enclosure height and type, would be pretty close.

    If in doubt, get comparable ratings and triangulate, find a median amongst the manufacturers. It will not be perfect but better than a wild guess.

    My $0.02

    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
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