BTU Rating of Cast Iron Convectors

Neil_5

Michael:

Why would it be per sqft when the convector is like a BB only a bit wider? Arent they measured by feet? Linear feet?

Neil

Neil_5

Convectors Rating

I have the cast iron convectors with recessed cabinets around the house. They have 3 tubes running in between the fins. Would like to know the BTU rating per feet if I can?

michael_15

A good resource

Try http://www.burnham.com/pdfs/htghelper.pdf. You'll find cast-iron convectors on page 45.

You can convert from the square feet EDR to BTU using the temperature of your system. It's about 240 BTU/sqft for steam, around 170 BTU/sqft for 180 degree hot water.

-Michael

Unknown

Convector Ratings

Although there are some ratings in the Heating Helper, these are only representative samples of various types in the field. If what you have are actually convectors, you will need to know the depth, width and height of the cabinet as well as the number of elements installed (some have more than one tier) to properly determine the outputs. Widths and heights of the cabinet are what generally increase or decrease the outputs. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Neil_5

Muti Tier

I thought that can be done, I made a post a few weeks back asking if I can piggy back to increase BTU output from said convectors, but no reply.

Thanks Glenn
Neil

Unknown

Multi-tiering

elements in convectors does not generally increase the output very much. The reason for this has to do with the devices name. It is a convector because it convects air through itself. The element is there to heat the air as it passes through but without reducing the convection principle by any appreciable amount. Adding another tier will decrease the air flow and will only give you about 30% more output. I have never seen cast iron elements double-tiered however.They generally have legs on them to support their weight. Any twin-tiered convectors I have seen have always been copper-finned elements and the cabinets were far in excess of the normal 20" high. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Neil_5

Glenn

Cabinet Depth is 8 1/4", lenghth is 64 1/4" and Height is 24"

Now the # I see in the copper chart is 79.4. What next to determind the BTU output at 180*?

Thanks,
Neil

Unknown

Outputs

If your elements are cast iron, then the rating of that convector is 70.4 square feet. If they are copper the rating is 79.4. Either way the output in btuh will be the square footage rating multiplied by a factor of 170 btu/square foot of radiation. For the cast iron elements this will be 11,968 btuh and for copper 13,498 btuh. Hope this helps.

Glenn Stanton

Manager of Training

Burnham Hydronics

www.burnham.com

Neil_5

Glenn S. Update

Remember my second problem was the quick drop in supply temp when the bioiler fired up? Well last night I checked it out; it is wired: the circulator only comes on when the boiler fires, when the boiler shuts down, the zone valve remains open (as per the STAT) and the circulator is off!!! So all along I thought the circ was on

Will rewire tonight. Question: In the mono flow setup that I have, with just the zone valve open and the circ off, would I have any circulation, if any, would it be sufficeint to flow through the convectors? If not, all that gravity circulation was just heating the main pipe?

Neil