Want to build custom radiator cover w/temp-sensitive fans to distribute air


Old 10-22-18, 07:19 AM
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Want to build custom radiator cover w/temp-sensitive fans to distribute air

I have a steam radiator system that works pretty well in most rooms. In the kitchen, however, our radiator is in the corner and because of cabinet/counter placements, the natural convection doesn't work very well and we're left with some very cold spots (and what seems like a lot of lost heat warming the cabinets...)

So what I'd like to do to solve the problem is build a custom radiator cover that has built in fans that will turn on when the interior temperature reaches a pre-set level.

My inspiration came from a home theater cabinet we have, which has cooling fans with a thermostat attached, so that air flow starts when the unit gets too hot. I thought - why can't I do this for my radiator cover? When the temp gets too hot inside the cramped area, the thermostat kicks the fans on and pushes some of the air out into the room.

Is this a stupid idea? I didn't grow up with radiators and obviously have never tried this. I'd love any feedback.
These are the fans I'm thinking of using:
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Old 10-22-18, 11:07 AM
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I've seen renovations mainly done in the summertime where no one has given any consideration to the heat and rads and baseboards have gotten buried under counter tops and and confined locations where they all of a sudden do not radiate the heat into the room.

You then get called in and are expected to perform miracles. They don't understand that heat can't go through walls or counter tops like Superman's xray vision.

I haven't had any practical experience with what you suggest but NO, I don't think it's a stupid idea. Anything that gets the heat from a remote location to where it can be used sounds like a great idea to me and would like to know how you make out when you're done,

Sounds very interesting, good luck.
Old 10-22-18, 02:13 PM
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Post some drawings and a picture of the existing rad and some of us will give recommendations and possible ideas.
Old 10-22-18, 03:01 PM
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Although I'm strongly inclined to go with passive circulation as a matter of principle, given the efficiency of many small fans, I can see the logic.

I've got an old farmhouse with a sunroom addition that is unfortunately located on the cold northwest side. Fortunately, It has 2 doors into the main house. One door is near the "hot" heat vent, directly above the furnace, the other door is near a cold air return. Passive circulation works in spring and fall. Dead of winter, I add a 6" fan to push warm air into the sunroom, which is generally enough to keep it comfortable and warm enough that the 240v baseboard heaters don't have to kick in.

I'm currently using a USB powered 4" computer case fan to cool a second-hand plasma TV that I use as a media monitor, I guess you could do something similar if you have a power outlet nearby. I've ran the numbers and found that a 5V USB powered computer fans doesn't draw enough power to really worry about, so you might just add a computer case fan and be done.

Last edited by Hal_S; 10-22-18 at 04:40 PM.
Old 10-22-18, 03:57 PM
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I think it's a great idea if implemented properly.

FWIW: you might also consider some sort of thermostat arrangement whereby the fan is energized when the piping to or from the radiator reaches a certain temperature set point, and the fan is de-energized when the pipe temp. falls below that temperature. Similar to the way a kickspace heater works.
Old 10-23-18, 12:30 AM
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Cheap Fix

Had similar problem with radiator on bay window wall. Used a $15 PID temperature control https://www.ebay.com/itm/Dual-Digita...FE0N:rk:1f:0 and 4” square box fans.

The PID thermocouple sensor is clipped to feed pipe on radiator. Set PID control to turn on fans at 90F and off at 85F. Works great!

PID's can be challenging to use. Would recommend practicing setup on bench before installing on system. Male sure to buy one that runs on 120 VAC with Fahrenheit scale.

I also use a PID for aquastat / control of oil fired water heater. PID alarm contacts are set to turn off at over temp setting.
Old 10-23-18, 04:57 AM
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Originally Posted by doughess
Used a $15 PID temperature control
There are also "thermocube" plug adapters, that provide 2 temperature controlled outlets.

I use the on-at-78' and on-at-120' plugs to control attic fans
Old 10-23-18, 05:07 AM
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Do a search for "temperature controlled fan" and many options will appear. This is the first sight I clicked on and it looks like they have several fan options that will do what you want.
Old 10-23-18, 03:16 PM
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Did not want radiator fan control blowing cold air at beginning or end of heating cycle. At 90F air is sufficiently warm to start fan. Used 85F to make sure fan turn off air is above room temperature.

Fan control is not universal. Those other controls in posts are less accurate and have much wider delta-T on-off temperatures.

Attic fan control with 120F on??? Whole idea of summer attic ventilation is to lower heat load on occupied rooms. With 120F fan control attic is 50F higher delta-T than room temperature.

I try to keep summer attic temp 10F less/below outside ambient. So at 95F outside the attic only 105F. Those into heat load calculations should appreciate the difference of 10F not 50F delta-T.

Use room thermostat in attic for summer fan control. Fan on at 85F off at 80F. Most of summer do not have to run AC.
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