Flame detection problem

I find it very difficult to see the flame that powers our motorhome fridge due to the odd angle and sometimes backlighting via the ventilation grill behind the fridge.

The viewing window for the flame is about 15mm in diameter and is situated at the back of the fridge.

I'm sure I've wasted a lot of time trying to light a fridge that's already lit so I'd like a better flame detection device.

What would be my cheap, and/or easiest options? Would an eBay IR thermometer work in these circumstances (when looking through a small plastic window)?

Tim

Reply to
Tim+
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I would suggest experimenting with a thermocouple with a meter wired across it, as a simple solution.

As the thermocouple gets hot, it will generate a tiny voltage and current.

The IR meter, would just see and measure the temperature of the plastic window, it will not see the flame.

Reply to
Harry Bloomfield

Ah, I was afraid of that. Thanks. Messing about with a meter seems a bit fiddly and I see on eBay I can get a basic flame detection circuit for about £13 plus postage.

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I might go down this route unless anyone has any better suggestions.

Tim

Reply to
Tim+

How about using a dental mirror to help you see the flame. It's much easier to move the mirror than to make sure that your head is in exactly the right position to look down the sight tube.

Reply to
Roger Mills

I had a thetford brand 3 way fridge in my motorhome, got one as soon as they became available to the public in the early 00's and whilst it had auto ignition that ment you just switched the main power selector switch to gas, the igniter started clicking, then you pushed the gas thermostat in (no need to adjust the setting dial as the power selector switch operated a solenoid), when the clicking stopped the flame was lit... hold for a few more seconds and all was well.

But it also had a handy flame level meter on the panel with the knobs and switches, this was just one of those little moving iron meters that have the scale at 90 degrees to the movment, and a bent needle... like a signal strength meter on a CB but smaller, and to run it, the single thermocouple which ran the safety cut out in the thermostat knob had a couple of push connectors spliced into it, which the meter connected to and thus read the tiny voltage level,

Kind of looks like those boiler thermocouples with interrupters, but i am not sure they are the same, as nothing was interrupted, the gas valve thermostat was mechanical, as was the safety devise for if the flame went out, and the igniter unit was a totally separate item switched on via the main power selector, and it ran it's self.. shutting off when it detected the flame, starting again when no flame was present (so when you run out of gas, it clicks away all night until you hear it... as the gas always runs out at night)

So, possibly if you can find the correct kind of thermocouple you can use it to run a flame level meter (mine showed me the flame size varying with the thermostat, which was sort of handy) Or you could get an electronic igniter box and fit it to the fridge, one which does the auto shut off when it detects a flame (so not a cooker one) and use that to indicate when the flame is lit.

Or maybe a simple remote reading thermometer, you can get digital ones for about a fiver, clip the sensor to the box that surrounds the gas flame and have it read when that gets hotter than ambient as an indication the flame is lit, as it wont get as hot as the flue or flame it's self, so you don't need a high reading unit, 0 - 100 degrees should do it, but don't quote me on that, i never measured the temp of my flame... and my fridges built in meter just had a red and green area, but i could see by how far the needle rose when the gas valve was open fully or closed down as the fridge was at temp.

Reply to
Gazz

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