Radiator vs. radiator

MattRuocco2

Long story short, I made a huge mistake by removing a "tall" radiator that was blocking a bay window and put in a cast iron baseboard unit that puts out little heat. The radiator that was there was:

16 rung
27"L x 24"H x 5"W

I want to buy a radiator on ebay that is:
14 rung
35"L x 20" H x 4 5/8" W

This will fit in under the window but i don't know if it will be sized correctly for the room based on the old radiator. The old radiator really heat up the room so i was comfortable with the output. Any help is appreciated. One pipe system if that matters.

Jamie Hall

Well, they're close. How many columns in each section ("rung"?)

MattRuocco2

both radiators were/are double column.

Fred

When you say "Rungs" do you mean sections? If so, and they are both two columns wide, why is the old one that had two more sections than the new one eight inches shorter than the new one? We really need to know the specifics of each if you want an accurate comparison. I would say they are close but the devil is in the details when calculating radiator EDR.

MattRuocco2

sections. sorry, the ebay post refers to them as rungs. here's pics of both. the old one has narrower sections than the new one i may buy, which is why it is shorter. i need a radiator that is no taller than 20". The old radiator is the top pic.

Abracadabra

pics from the side to determine number of tubes/columns

MattRuocco2

OK, a pic clears it up. New one is top pic. 4 for old, 3 for new. hope that isn't a deal breaker, this radiator will fit!

Fred

That four tube (old one) is between 32 and 40 EDR. (the general guide I have says a four tube is 7" wide. You say yours is 5" ?? Anyway that's the reason I have a range for the EDR.

The new one is 25 to maybe 30 EDR. (In this case, the range is due to the fact those tubes are a bit larger and spread out a bit more, almost like old hospital radiators.

The new one is probably 20% to 25% smaller than the old one. May still work fine as most original radiators were a bit oversized anyway.
Also, be aware that if you replace the old radiator, you will need to get the valve that mates with the radiator spud or put a new spud and valve on your installation. The valve and spud are matched pairs and the old spud, in the radiator you purchase will most likely leak when connected to your old supply valve. From the looks of the pictures, you may also need to raise your supply pipe as well. The new radiator looks like it sets higher than the old one.

MattRuocco2

Thanks to all of the experts helping me. could i ask what the EDR would be for the attached baseboard unit? 86" long, cast iron. i'm trying to convinve the wife with math that going back to a radiator is the better choice.

EBEBRATT-Ed

Need to know pipe size fins are mounted on, #of fins per inch and size of fins (4" X 4"?) and how many feet of fins.

MattRuocco2

thanks.
total pipe is 91" x 1 3/4"
82" has fins
5 fins per inch
fin size is 3x3

Leonard

What I see on the 2 cast iron rads is looks like the 4 tube one has more surface area to heat the air with. Also the taller one likely creates a stonger "chimney" effect for faster convective air current flow. ( gives off more BTRU/hr)

Jamie Hall

That fin tube has an EDR of about 37. Right in the same ballpark as the radiators you are looking at. However, it has almost no mass, relatively speaking -- so although it will heat up slightly more quickly, it will cool off a lot faster and produce less heat overall.