Running a 208V radiant ceiling heater from 240V

Probably... the heater no doubt has a positive TC. If *I* were sweating overheating (no pun intended) I'd make it adjustable cycle-skipping until I got the same net Watts.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

Yeah, just like that.

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Nice.  Inherently self limiting, you clever devil. :-)

That's correct. Grainger has 500 VA buck boost transformers for about $140. But you could use this 24 V 10 A tranny from MPJones for about $18:

216 volts should be fine, especially if your 240 V line is a bit low.

Paul (excuse the top post)

That would be correct. Six panels might be overkill. I don't know how large your basement is, and the height of the ceiling etc.. but with radiant heat your only trying to make it comfortable. I mounted a small 2' X 4' panel over my bed and the room can be at 40 F and the bed feels toasty. So, if you only plan to occupy a specific area just mount panels in that area with individual controls (bucking auto transformers)

The downside of radiant heat is that thermostats that sense air temperature don't do a good job of maintaining a comfortable "feeling." So you might be the thermostat in that situation.

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The room I want to put it in is 12x20. Each panel is 2x2.

Well, that is something I should consider now. I currently have a wall-mounted line voltage thermostat which is used with two 1kW electric baseboard heaters. I would like some advice from somebody who has experience with these things about how many watts per square foot I should have, and what to do with the thermostat.

My main reason for wanting the ceiling heat is that hot electric baseboard radiators + small kids + toys = potential danger.

John

2 kW should be plenty for a 12 x 20 room unless the insulation is very poor.

Running one in series with a diode will reduce power to half what it was without, which comes to about 250 watts per panel.

Put both in series and put a diode in parallel with each panel. Watch the polarity of the diodes!

Thomas

Everyone's calculations are missing the very important fact that heaters generally have a notorious TC.

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Radiant heating panels don't. Most all I have seen have mineral insulated heaters.

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(thermal coefficient of resistance?)

I thought nichrome was fairly good in that regard, it's certainly much better than tungsten or stainless steel.

Bye. Jasen

Definitely better in that regard than most other alloys not produces specifically for low thermal coefficient of resistivity. This site says that Nichrome 80-20 (commonly used as heating elements) has a coefficient of about 100 ppm/degree C.

At modest temperatures, tungsten is more like 4600 ppm/ degree C.

316 stainless is harder to find out about, because it isn't ordinarily used as a resistance heater element. I may have to do some testing, because I use stainless steel wire (brand name Beadalon) to heat my motorcycle gloves.