replace thermocouple

[Viper1]

Can anyone tell me how to replace the thermocouple (external Temp)? I tried to 'unscrew' where the thermocouple goes in, but all it did was fray it terribly.
Thanks

[hankua]

If I'm understanding correctly; you tried unscrewing a thermocouple without detaching the connection? The wire has to come loose from the meter or phidget before wrench turning. Similar to unwinding a water hose that's kinked up.

Hopefully it's still functioning; I would get replacements from Mr. Li, although Procon in China might have something inexpensive.

[Viper1]

Thanks, but how do I remove the braided wire from the nut? It doesn't pull out. Is there a 'trick' to that?

[edtbjon]

You don't... You have to detatch the yellow connector (to your meter) or the connection to the Phidget (if your're using that). Then you have to see to that the wire is free to spin before turning the TC itself.
Now, you can use and move the MET TC to the ET position if you have MET installed while waiting for a replacement TC. (Waiting for stuff to arrive is always a loooong wait. But getting a replacement from Mr Li is usually quite fast, as TC's are off the shelf items and they are delivered as normal mail.)

[Viper1]

My problem is that the 'nut' keeps rotating and does not seem to be threaded at all. How do I remove the wire from the Huky itself?

[edtbjon]

I take it you're talking about the ET (Environmental temp) TC which sits in a brass adapter. That TC is simply screwed into the adapter, which in turns is screwed into the front on the right side. It sounds strange that that particular one just rotates, as the threads are M8 and 1/2" (?) respectively. I.e these threads shouldn't just break down without rather severe force.
The other two (BT and MET) are held to the front plate with nuts on the back of the plate. You do have to dismount the roaster, i.e. the top cowling and the front to access the corresponding nuts, which you have to do if the TCs are loose and spinning.

[Viper1]

Ah, got you, that makes sense. Now, is it easy to remove the cowling and front plate? I'm not the handiest guy in the world.
Rob

[hankua]

I can reach inside the front plate and feel the nut behind the BT thermocouple. Is that the one your trying to remove?

[Viper1]

Nope, too easy. It's the ET probe on top.

[edtbjon]

If it's the one on top at "one o'clock" (That TC is usually denominated MET...), you're in some luck, as you don't have to remove the front plate. To remove the cover, you have to unscrew the ten insex (metric) screws along the front and back edges and just lift the cover off. These screws strips quite easily, so take care. (There is an insex key in the tools bag, but if you can source a high quality one, it's even better.) Once done and you put the machine together again, start on the top and don't fasten the screws, just fit them with a few turns.
Also, the MET is the "least significant" TC (IMHO)... You can roast along without it until a new one is in your mailbox.
Once you have the cover off, you can really see and Admins the very "simple" but effective construction of the Huky.

[Viper1]

Awesome, and thanks. I'll give it a whirl tonight

[Chert]

This is germane to the idea of replacing the thermocouple.  If you look for a replacement, what is the appropriate thread size for the faceplate?

@edtbjon: I read you have ordered a 17 mm TC for the BT position, I want to follow your lead, what thread size do I need?

[SusanJoM]

If it's the same as the one for the ET position, it looks like it's an M8 ??
https://www.hukyforum.com/index.php?action=gallery;sa=view;pic=28

[edtbjon]

Well, I'd say it's M6, which is (looks) pretty close to a normal 1/4". If' it's easier to source a TC in the States with 1/4" mount, you can easily enlarge the hole that little bit (about 1/64" or .4mm). Btw, the spanner width for an M6 nut is 10mm (and for an M8 nut it's 13mm...).

The link to the german (made?) TC that beananimal talks about is here: https://www.sensorshop24.de/temperaturfuehler/einschraubfuehler-mit-kabel/einschraubfuehler-mit-einem-m6-gewinde/einschraubfuehler-mit-m6-gewinde-und-17mm-einbaulaenge/einschraubfuehler-bis-550-c-nicr-ni-typ-k/mit-aderendhuelsen/

(I ordered two of them and I'm still waiting for them to be manufactured... I'll report back on the pros and cons with a shorter TC once I've done some testing.)

Edit: The original TC's are indeed M8, but are secured by a 10mm nut, which isn't the first choice. (See my ranting above in this post...)

[beananimal]

I am almost sure that the original TCs are M8 with a 10mm nut, but cannot check today. I bought some M6 as I drilled additional holes.
Follows the link above you can find M6 and M8.
Sorry if I confused you.