PID went crazy....

[RegisG]

This morning I was marveling at how well the PID has helped my casting. Then about 1/2 hour into casting with my new 357 mold, I noticed the PID flashing and temp rising. I unplugged it at 422c (791f). I keep it at 375c (707f). I waited a little while and plugged it back in. It was at 360c. I watched it as it climbed to 380 and then fell back cycling until it finally settled back at 375.

Any ideas? Or, has anyone else had similar? I am using 40a controller

Regis

[ebruce]

It could be a loose connection on the thermocouple, or a failing thermocouple.

[Beagle333]

The little twisted part at the tip of the thermocouple is either loose or touching the inside of the sleeve (stem) of the probe. It's time for a replacement. I have not been able to recover any of them when this happens, but fortunately they are cheap. I ordered a 6 pack of them, just so I wouldn't have any down time when it happens again. (because it will!) ;)

[RegisG]

Appreciate quick answers. The old saying is " if 2 people agree on anything, that makes it a fact". I will do the same as Beagle33 and order a 6 pack.

Thanks,
Regis


The little twisted part at the tip of the thermocouple is either loose or touching the inside of the sleeve (stem) of the probe. It's time for a replacement. I have not been able to recover any of them when this happens, but fortunately they are cheap. I ordered a 6 pack of them, just so I wouldn't have any down time when it happens again. (because it will!) ;)

[popper]

Wiggle the wire and see it change. Themocouples are spot welded, not twisted - when done correctly. Probably the insulation going bad or too sharp a bend on the wire - usually at the end of the spring part of the probe. Even Kynar insulation typically used is only good to 500F.

[Walter Laich]

where does one order 6 at a pop?

[RegisG]

Yep, I've been looking too since that was mentioned.


where does one order 6 at a pop?

[georgerkahn]

I have/use three PIDs, and all were built from Auber components. The "key", imho, is the thermocouple. Some have a maximum user range of 700*F, which is enough to make future operation go bozo. I keep one spare, just in case, and do believe one gets what they pay for: again, mine came from Auber. Make sure you select the correct TYPE (e.g., "K") thermocouple, connector to your PID, etc. *MY* source is: http://www.auberins.com/index.php?main_page=advanced_search_result&search_in_description=1&keyword=6%22+k+thermocouple
Good luck and BEST!
geo

[Yodogsandman]

Another source...

http://www.ebay.com/itm/3m-High-Temperature-100-1250-Degree-Thermocouple-K-type-100mm-Probe-Sensors-OV-/301333037049?pt=LH_DefaultDomain_0&hash=item4628d93ff9

[leadman]

Amazon also has thermocouples for sale. It is good to find a seller that has a USA warehouse that they ship from. Hong Kong and China take weeks most of the time to get here.

[Beagle333]

I got mine from China. They're cheap, but yes it does take about 2 weeks to get here. I think I have had two that have failed, but I still got 3 that work perfectly and a few backups still new-in-bag. :D