How do I know which thermocouples to get for my kiln?

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How do I know which thermocouples to get for my kiln?

L&L has used a lot of different style thermocouples over the years.

With thermocouples there are different TYPES, and within the various types there are different STYLES.

Some different types are Type N, Type R, Type J, Type K, Type S.

L&L uses Type K or Type S.

Type S are expensive but very long lasting thermocouple made from Platinum and Platinum-rhodium.

L&L uses three styles of S thermocouples:

  1. T-G-SXXX/00 is a 5/16" diameter 4.75" (120mm) long thermocouple.
  2. T-G-SXXX/06 is a 5/16" diameter 6.3" (160mm) long thermocouple.
  3. T-G-SXXX/08 is a 5/16" diameter 8.66" (220mm) long thermocouple.

Type K  thermocouples are inexpensive but they do not last as long as the Type S thermocouples.

They are made from Alumel and Chromel (base alloys).

L&L currently carries five different styles of these Type K thermocouples. Additionally there have been other Type K styles used over the years. The five we currently carry are

  1. T-G-E800/00 is an 8-gauge thermocouple. This thermocouple has an exposed metal tip sticking out of the ceramic tube inside the kiln. On the outside of the kiln it looks like a white ceramic football with two pairs of little gold screws on it. It is 1/2" in diameter and 5" long.

  2. T-G-TUBE/00 is a ceramic protection tube that can cover the T-G-E800/00 thermocouple.  The tube is closed and rounded off at the end that sticks into the kiln. Outside of the kiln, the end of the tube sits behind the ceramic football on the T-G-E800/00 thermocouple. 
  3. T-G-E807/00 is two inches longer than T-G-E800/00, but otherwise it is the same.  It is used on kilns with walls that are thicker than 3" such as Easy-Load and Hercules front-loading kilns. 
  4. T-G-TUBE/07 is the longer ceramic protection tube that fits over T-G-E807/00
  5. T-G-E23M/05 is a special metal covered thermocouple called a Pyrocil Thermocouple.  It is 1/4" in diameter and about 7" long. The extra length needs to be kept on the outside of the kiln. The thermocouple tip should only enter into the kiln at the most 2". The further away the ceramic football shaped connection block on the outside is from the side of the kiln, the longer the thermocouple will last. This is because of an epoxy plug at the back of the metal tube. Once that plug melts out of the tube, the thermocouple is ruined.
  6. T-G-E140/00 is a 14 gauge thermocouple. It is for low-fire applications only. This is a 1/4" diameter thermocouple whose 14 gauge wires match all the very old 3/8" diameter thermocouples that L&L used until around 1998. If someone with very old thermocouples wants to, they can use the 14 gauge wire from the new thermocouple and house it in their old 3/8" ceramic insulator tube and not have to widen their thermocouple hole. None of the new kilns L&L makes use a 14 gauge thermocouple because they do not last very long going to temperatures over 1950°F.
  7. Click on this link to see all available thermocouples, thermocouple mounting hardware, thermocouple extension wire, thermocouple protections tubes, etc.

Additional Actions to Take

  1. Unplug kiln.
  2. Remove or hinge open the control box.
  3. Remove the Thermocouple Lead Wire from the Thermocouple.
  4. Unscrew the Thermocouple from the kiln.
  5. Remove Thermocouple.
  6. Install a new Thermocouple and screw in place.
  7. Replace Thermocouple Lead Wire and tighten. Be sure to get red matched to the MINUS (Negative) sign and the Yellow matched to the PLUS (Positive) sign.

See this video: