Any Thermocouple Experts Here?

  • 3rdtryguy
    Central Mn
    Posts: 1305
    #2183847

    Can a thermocouple be ID’d from the number stamped on it? I was getting these from ASAP Heating but they are sold out and I have searched with no results. This is for an Orbis Colorama 20,000 btu direct vent wall heater I have in my fish house. Orbis went out of business about 10-12 years ago but I can’t believe they made their own thermocouples. I’ve tried some pretty big plumbing & Heating suppliers with no luck. The SIT numbers are stamped into the wire/tube part. Numbers have different first 3 numbers but came from ASAP and fit the same. Can anybody help?

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    Dave maze
    Isanti
    Posts: 918
    #2183894

    Typically if you have repeated thermocouple failures the gas valve is the culprit. Too hot of a pilot flame will melt them. But most of the time the internal holding coil in the valve is weak. Have you tried a standard honeywell thermocouple to see if it will fit?

    Reef W
    Posts: 2168
    #2183901

    The 0290144 is the part number it looks like and some places list in format 0.290.144

    Yours is 320mm and I think this is same (I think) but 600mm if that will fit https://a.co/d/7SiEq8E

    Mike W
    MN/Anoka/Ham lake
    Posts: 13194
    #2183905

    Have you tried just a standard $10 thermocouple? Most of the ones I’ve dealt with seem pretty universal.

    3rdtryguy
    Central Mn
    Posts: 1305
    #2183947

    Huge thank you guys. Dave, I’ve been told that Minnesota does not have very strict purity standards. I don’t know if that’s true or not, but I do know that I clog up orfices, never could spell that word, which causes these things to soot up more than it does melt them. But what I’m taking this whole thing apart, I don’t know if it’s that or melted and I wanna make sure I have a good one to go in there. Reef, I did screw up one of those measurements I had in my diagram. The first fraction I had on there was 5/6 it should have read 5/16. And my caliper says that the thicker shoulder end of my thermocouple is 6.48 mm with the smaller and being 5.92 mm, it’s approximately an inch and 3/8 from the shoulder part, the thicker millimeter, to the end of the thermal couple. Isn’t that the most important measurement because the thermocouple has to go up to that shoulder to have the tip of it in the pilot. So doesn’t that become a very important number as far as using universal ones? You guys really helped me out and I appreciate it and as Reef had in his reply, it looks like if I would’ve just dropped that first four of the stamped numbers that I would’ve come up with some of the same results that you guys did. And I believe the SIT stands for the way that it goes into the gas valve? oh well, back to the search engine I will try those two companies that you left me Reef. thank you

    Mike W
    MN/Anoka/Ham lake
    Posts: 13194
    #2183975

    I believe that’s why the universal thermo couples come with the addition clips for installation, so you can use them for various appliances. The most I’ve looked at when purchasing one is the length of the copper lead but got to say I have installed some long ones where they are not needed and they still work.

    I see you can get a universal snap fit thermo couple with 4 different installation clips for $6.50. My guess is one of those clips will work.

    For sooting issues sounds like a fuel/air mixture issue. Getting nice blue flames with very little to almost no amber? If not might be issues with vent pipe or lack of fresh air getting to the flames.

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