Thermocouples

**Hypoman** · 03-31-2012, 01:48 AM

When tearing apart a gas furnace, water heater or stove(the three "main" gas appliances that scrappers get) You should always set aside the thermocouple. It may contain Platinum! There are 11 different types of thermocouples>>>HOLY COW!! AAAAAÀ, WHAT DO I DO! Learn how to identify the type you have you silly goose!!!!!!!

BUUUUUT FIRST! CHECK OUT THIS LINK TO LEARN ABOUT
THERMOCOUPLE T H E O R Y
http://www.sensortecinc.com/docs/technical_resources/Thermocouple_Theory.pdf

The types of thermocouple are:
K: Chromel NOT IMPRESSED! http://www.ladyada.net/learn/sensors/thermocouple.html FOR more info on type K

E: Chromel-constantan WEEEEAKKKK

J:Iron- Constantan BOOOO

N:Nicrosil-Nisil PUSHHSHHHHHAW

**Hypoman** · 03-31-2012, 01:50 AM

B: Platinum-Rhodium SHOW ME THE MONEY!!!

R: Platinum-Rhodium " "

S: Platinum-Rhodium SHUT THE FRONT DOOR!

T: Copper-Constantan

C:Tungsten-Rhenium

M: Nickel, Cobalt, Molybdenum

no pic........ sorry

Chromel-gold/iron

nor here AAAAAAAH

FYI-----> CONSTANTAN IS A COPPER AND NICKEL ALLOY :eek: :eek:

**Hypoman** · 03-31-2012, 01:52 AM

HERE IS AN INTERNATIONAL COLOR CODE FOR CERTAIN TYPES FOR YOU VIEWING PLEASURE!!!!!!!!!!!

:confused:

**Hypoman** · 03-31-2012, 02:06 AM

Type K (Chromel / Alumel)
Type K is the ‘general purpose’ thermocouple. It is low cost and, owing to its popularity, it is available in a wide variety of probes. Thermocouples are available in the -200 °C to +1200 °C range. Sensitivity is approx 41 µV/°C. Use type K unless you have a good reason not to.

Type E (Chromel / Constantan)
Type E has a high output (68 µV/°C) which makes it well suited to low temperature (cryogenic) use. Another property is that it is non–magnetic.

Type J (Iron / Constantan)
Limited range (-40 to +750 °C) makes type J less popular than type K. The main application is with old equipment that can not accept ‘modern’ thermocouples. J types should not be used above 760 °C as an abrupt magnetic transformation will cause permanent decalibration.

Type N (Nicrosil / Nisil)
High stability and resistance to high temperature oxidation makes type N suitable for high temperature measurements without the cost of platinum (B,R,S) types. Designed to be an ‘improved’ type K, it is becoming more popular.

Thermocouple types B, R and S are all 'noble' metal thermocouples and exhibit similar characteristics. They are the most stable of all thermocouples, but due to their low sensitivity (approx 10 µV/°C) they are usually only used for high temperature measurement (>300 °C).

Type B (Platinum / Rhodium)
Suited for high temperature measurements up to 1800 °C. Unusually type B thermocouples (due to the shape of their temperature / voltage curve) give the same output at 0 °C and 42 °C. This makes them useless below 50 °C.

Type R (Platinum / Rhodium)
Suited for high temperature measurements up to 1600 °C. Low sensitivity (10 µV/°C) and high cost makes them unsuitable for general purpose use.

Type S (Platinum / Rhodium)
Suited for high temperature measurements up to 1600 °C. Low sensitivity (10 µV/°C) and high cost makes them unsuitable for general purpose use. Due to its high stability type S is used as the standard of calibration for the melting point of gold (1064.43°C).

HOW DOES THIS HELP ME !!!!!

BECAUSE THE HOTTER AN APPLIANCE NEEDS TO GET( ALL THE WAY FROM HOME FURNACES TO INDUSTRIAL FURNACES AT THE STEEL MILLS!!!!!) THE MORE VALUABLE A THERMOCOUPLE YOU HAVE !!! WOO-HOO!

DON'T FORGET KIDDOS, THERMOCOUPLES ARE STARTING TO BE USED IN ELECTRONICS!!!!!

http://www.picotech.com/applications/thermocouple.html

**freonjoe** · 03-31-2012, 09:53 AM

Thanks Hypoman, I'm going to start another bucket for thermocouples.

**BRASSCATCHER** · 03-31-2012, 10:16 AM

Thanks hypo man another thread I just subscribed to...thanks again

**Bear** · 03-31-2012, 11:41 AM

Thanks! Hypoman

How timely! I just began my first old (60s? ish) furnace, and have another one yet to retrieve

**Ohio Scrapper** · 03-31-2012, 12:08 PM

Excellent information Hypoman, thanks for taking the time to post it!

**mikeinreco** · 03-31-2012, 02:40 PM

Ok now who do I market these to.....EBAY?

**BurlyGuys** · 04-01-2012, 10:15 AM

Originally Posted by freonjoe

Thanks Hypoman, I'm going to start another bucket for thermocouples.

Yeah, me too!

**Bear** · 04-01-2012, 11:01 AM

Mine had 3 little sensors wired in at several levels (middle ways up, 3/4s, and another near the top), Would the "thermocouple" be near the pilot light? where the fire is at? I saw one piece thought was a temperature thing, I'd cut the wire taking it apart, just looked like solid copper about 12 or 14 ga

**Hypoman** · 04-01-2012, 11:33 AM

it should be right next to it b/c it has to regulate the temp thats coming off of it.

**Bear** · 04-01-2012, 11:53 AM

has a little sending unit end on it, i'm expecting that's the thermocoupler on this one, basically just copper i guess

**Hypoman** · 04-03-2012, 11:06 AM

To quick test a wire to see if it is platinum: Heat the wire to red hot and air cool, if the wire looks exactly the same as before you heated it..... it's probably platinum! If it is discolored or rainbow colored.... it is not.

This info came straight from a refiner so I bet it works!

**NHscrapman** · 09-05-2015, 08:36 AM

bump for awesome information!!!

**eesakiwi** · 09-06-2015, 06:03 AM

I have been told that on the Platinum thermocouples. The Platinum wire is not just in the tip, its the whole length of the wire as well.

This makes sense to me, any metal/metal connection is actually a 'thermocouple' and you want to only have one connection and thats the one that reads the tempature.
If theres more than one connection, as that heats up, its makes its own thermocouple and changes the gauges reading.

I have been saving every thermocouple I find. Microwaves, ovens, washing machines, dryers etc etc, I guess they are not worth much untill I find out what they are made of.

**junkfreak** · 09-06-2015, 09:08 AM

Gotta love the archives! Thanks for bumping this thread NH! I have a barrel of them some where. Never knew about the platinum on some. Great info.

**chrenton** · 07-10-2019, 11:01 PM

We buy a similar looking part, but this part only... no thermocouples.

NEVER cut the flex capillary on a mercury flame sensor!

Buying Mercury Flame Sensors, $30 each (= $150 lb!) Limited time only!
White Rodgers brand ONLY. Models 3098-134, 3098-xxx, 3049-xxx, 3094-xxx, (xxx can be any number after dash) 3046-5, 30A46-5.

Full article at Scrap Metal Forum: https://www.scrapmetalforum.com/scra...#ixzz5tKimtac3

**kirstenblain** · 05-22-2020, 08:18 AM

Would a solder iron have a thermocoupler?

I’m pretty new to this, so I’m trying to get my mind thinking outside the box.

**eesakiwi** · 05-22-2020, 11:14 AM

Not likely, unless its a IC soldering station or something fancy.

I now know that I'm unlikely to find a rare earth metal thermocouple. Most of the ones i find are in electronics & are 1/2 Iron.

Thermocouples

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