Flame Sensor

I am racking my brain trying to find a safety device to put inline with my hot surface ignition and gas valves. Right now I have it wired with a time delay relay so I flip a switch, the ignitor glows for about 5 seconds then the gas valve is energized. This will eventually be automated by the PID I plan on installing. I am looking for some type of flame sensing relay I suppose. No, I do not want to have standing or intermittent pilots. I do not want to use ignition modules as I already have 2 and do not like the prepurge time (20 seconds). Please help me figure this out, I know there is a way to do this but I just feel kinda lost right now. I want instant heat when My PID calls for it but I also want to make sure when it calls for heat that the burners actually ignite. I know you can do this with standing and intermittent pilots with spark igniters but I don't want to have to wait for anything on my boil kettle specifically. I would like on/off heat for that instantly. Hopefully we can come up with some ideas?

can't you just use a standard flame sensor from white rodgers/honeywell/jci?

aren't they just contact closures upon sensing?

millivolt generators for propane systems use thermocouples to sense the pilot light.

You could probably use a thermocouple the same way. It gets hot, generates a small voltage, you use that somehow. If you don't want to reinvent the wheel and make it all yourself, you could probably find something like that but with an output of some kind to do what you want. I'm just rambling, I'll stop now...

passedpawn said:

millivolt generators for propane systems use thermocouples to sense the pilot light.

You could probably use a thermocouple the same way. It gets hot, generates a small voltage, you use that somehow. If you don't want to reinvent the wheel and make it all yourself, you could probably find something like that but with an output of some kind to do what you want. I'm just rambling, I'll stop now...

Click to expand...

^^This^^
I've changed a couple on my tankless water heater and one on my furnace... I think they're 0-10mV

Yea, so basically I was looking for a mv relay that I could install inline.

http://surpluscityliquidators.com/view_product/26819/212

That is kinda what I was looking for but can't find any anywhere. Its a 24v powered flame sensor. Found one but expensive.

Could you use a thermostat as a mV relay? But I think they run off 24v too...

Yeah they're 24v ac. Flame sensors and thermocouples produce a dc signal.

use a cadmium sulphide photo cell in a shroud tube like commercial flame safety systems do, look for a Honeywell C455 or similar.

Kladue, I searched for that part number and I didn't see anything, I can't believe its this difficult to do this. There has to be something. I have my ignition module hooked up to my HLT now and its an entire minute between call for heat and actual flame rectification which I guess is fine for a recirculating mash, a minute won't kill me. I just want on off control with my boil kettle so I'll probably just have to get a standing pilot gas valve.