How do these work? (towel radiator timer with thermal control)

[ARWadsworth]

there are no instrunctions on the web site I have no idea how they work to control the temperature.

Anyone got any ideas? Will they retro fit a bog standard 2 hour electronic timer?

[Andy Dingley]

They control the power, not the temperature.

As a towel rail is uninsulated and fairly low power, it (in normal behaviour, without this add-on) simply runs at a vague temperature where losses balance heat input. Controlling power is thus a a reasonable open-loop control for temperature difference above the room ambient.

Neat gadget, and I can think of several other uses, but not for that price.

[fred]

In article , Andy Dingley writes

Wot 'e said, jpgs of the instructions here with a few more pics:

[ARWadsworth]

nagging doubt with the words "thermal control" staring me in the face.

Now who put the pz screws into the faceplate on the link fred gave?

Thanks to both of you.

Cheers

[fred]

Why that's to fix direct into the pine cladding, no backbox required.

Welcome

[Gordon Henderson]

Fancy dimmer switch...

Gordon

[John Rumm]

Reading between the lines, I would guess they are basically a PWM style "dimmer" with five discreet steps in effective output. The boost just turning it "full on" for a couple of hours.

So they "control" the temperature in the sense that they can select hotter or colder, but there is no feedback or temperature measurement.

(stretching the definition of "thermostatic" a tad!)

Sounds like it should.

[ARWadsworth]

I am so glad that I asked about the timer.

I suggested it this afternoon to the customer with the broken 2 hour timer. Her reply was "Oh will it be hotter then? The radiator never gets warm enough when I just use the electric bit"

I ordered a replacement 2 hour timer from my wholesalers.

[John Rumm]

Make sure she it turning off one of the rad valves - otherwise she may be trying to run half the heating system on a 200W heater!

[ARWadsworth]

I am not so sure about that, and it is certainly something that I have not considered before. A vertical element into a towel radiator should make the hot water rise into the radiator and if the pipework is from below then there will not be much heat loss into the rest of the system.

I will have to see what my IR thermometer says on the pipework to a towel radiator when it is heated by an electric element. I have only ever used it to tease my cat!

[John Rumm]

Indeed - much depends on the layout of the pipework and where in the system the rad is. A downstairs one could eventually kick off a bit of gravity circulation in the wrong circumstance - and you won't need much to take lump out of the available output of the element.

I had one in small rad (rad output about 400W IIRC) - but that was right at the top of a system on three storeys. It seemed to get it plenty hot enough.

;-)

I have a laser pointer that I call "Kitty Remote" you could get the cat to spin round and round in circles or chase the dot up and down the hall.

BTW you need to stick a bit of tape on the pipe to get a sensible reading from the IR thermometer - they get confused by metal pipes otherwise since the emissivity is readically different from what they are calibrated for.

[ARWadsworth]

Like this?

BTW you need to stick a bit of tape on the pipe to get a sensible

And the night sky!

[John Rumm]

itself without encouragement!)

Yes, well I suspect that is also a tad out of their temperature range. Mine only goes down to about -20 or something.

[Clare]

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hi guys, so can one of you tell me whether this is a worthwhile piece of kit? it seems awfully pricey. i just need a timer switch really I suppose - can you point me to a better value one? thanks

[Andy Dingley]

Indeed.