kanthal for flame rod?

[USAeng]

Is kanthal a-1 a good material for the center of a flame rod? I thought kanthal was some kind of resistance material... wouldnt a 316 stainless or inconnel work better? I do find some notes on people using kanthal for flame rods though, so what's the deal? is there a certain grade you should use? Thanks

 

[USAeng]

sorry, another question too... if one rod is made of stainless steel and you replace it with a kanthal rod would it create a problem because of the resistivity of the material? since the component that reads the return signal is probably calibrated to the stainless steel rod? thank you

 

[USAeng]

anyone?

 

[danw2]

I know that when my former boss, who is now 78 years old, was a kid doing combustion controls, the flame rods were made from Kanthal. It's been around for awhile.

Kanthal is made from iron, chromium and aluminum and has a higher temperature rating that its competitor alloy nichrome (80% Ni, 20% Cr).

I'm guessing that an alloy of iron and aluminum is cheaper than one with a very high percentage of nickel and some chromium, and that for the service involved with a flame rod, that Kanthal is the best material with the longest service life available.

Here's Kanthal's sales brochure comparison of Kanthal to nichrome:

I wasn't aware that any combustion control flame rod electronic control 'calibrated' to a stainless steel flame rod. I'm guessing that if the SS conducts the rectified current well enough to hold the flame safety relay "in", that SS would work, but why would you not use a material that's been accepted as an industry standard for so many decades?

 

[USAeng]

kanthal definately sounds like the better choice... thank you for the reply. I will be researching it more tomorrow. Thanks!