View Full Version : PID went crazy....
RegisG
08-25-2015, 09:56 AM
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
08-25-2015, 10:03 AM
It could be a loose connection on the thermocouple, or a failing thermocouple.
Beagle333
08-25-2015, 10:10 AM
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
08-25-2015, 10:37 AM
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
08-25-2015, 12:05 PM
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
08-25-2015, 10:24 PM
where does one order 6 at a pop?
RegisG
08-26-2015, 09:34 AM
Yep, I've been looking too since that was mentioned.
where does one order 6 at a pop?
georgerkahn
08-26-2015, 11:10 AM
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
08-27-2015, 07:44 PM
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
09-01-2015, 03:41 AM
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
09-01-2015, 05:22 AM
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
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