Do I Need A New Heating Element?

[centershot]

I'm having a problem getting my 20 lb. Lee pot up to temp. I use a PID for temp control, it seems to work fine when I'm casting WW or similar alloys at 700* or so. This past weekend I was casting round balls for my muzzle loaders, running the pot @ 800*, or trying to. It just won't get up that high, staying around 770*. The lead (pure lead) pours kinda' OK, but I get a lot of rejects due to wrinkles. I know the melt wants to be hotter to get better fill-out. Do I need to replace the heating element? This pot is about 12 years old, it has always run well, even better when I added the PID a few years ago. I haven't cast with pure lead in quite a while but I don't remember having this problem in the past. Comments?

[Hannibal]

Bypass the PID by plugging the pot in directly and see if you can achieve the temperature you want. If not you know the problem lies in the pot itself and then you can decide how to proceed. If it does heat to 800° or more then your PID is the limiting device and you can either continue to bypass it when casting pure lead or check into repair/replacement.

[Mal Paso]

Could be the Lee temp control interfering with the temperature. Turn it all the way up or bypass. To bypass connect the 2 wires going to the control, together.

[Maven]

You can try opening the top panel, polishing the contact points on the thermostat, and then bending the lower leaf down ~1/8".

[Rapidrob]

What is the range of the melt sensor hooked to the PID. What range have you set in the PID? How far down into the melt is the PID sensor? this is a big deal.

[centershot]

What is the range of the melt sensor hooked to the PID. What range have you set in the PID? How far down into the melt is the PID sensor? this is a big deal.

1) I don't know. It was supplied by JConn as part of the kit I bought quite a few years ago.

2) I did not set a range, I set the temp to 800*. It has always held the set point within 5* until now. It will hold the set point at 750* or lower if that is where I set it.

3) I try to maintain the tip about 1/2" above the bottom of the pot and about 1/2" from the sidewall.

[jsizemore]

Plug the pot directly to outlet and see if you get to temp or higher. If it does, then check the thermocouple output voltage. They do wear out after a while.

[centershot]

Plug the pot directly to outlet and see if you get to temp or higher. If it does, then check the thermocouple output voltage. They do wear out after a while.

OK, can you explain to me how that's done?

[oley55]

OK, can you explain to me how that's done?

Good question and fairly sure I know the answer but my understanding of the hieroglyphics depicted on multimeters and which to use when is limited at best. LOL

Watching for the responses....

[jsizemore]

A thermocouple produces a voltage (really small) that changes as temperature changes. If you take a voltage reading across the terminals as the temp goes up, you should see a change in voltage. If temp goes up and there's no change then it's bad. If it does then it's time to look elsewhere. Here's a little video that explains the principles involved:

https://www.youtube.com/watch?v=v7NUi88Lxi8

Over time you'll see a loss of available electrons from the heating and cooling process. Some will lose the connection between the differential materials that produce the voltage.

You don't need a super duper high dollar Fluke multimeter. Your just looking for the change in voltage. Now if you want to verify voltage output to manufacturers specs for the thermocouple then you need a whole gang of test equipment. Just changing the lengths of your thermocouple leads will change your voltage readings.

[Hannibal]

I'd definitely check to see if the pot heats up enough without the PID before I went through the trouble of trying to test/replace the thermocouple and recalibrate the PID.

[jsizemore]

I'd definitely check to see if the pot heats up enough without the PID before I went through the trouble of trying to test/replace the thermocouple and recalibrate the PID.

You got that right. A simple test is to grab the power cord with your hand and see if it gets warm or hot. Shouldn't do either. Test it with the back of your hand first.

[centershot]

OK guys, thank you very much for your assistance, I'll check it out in the morning!

[wv109323]

I don't think you need an element. They are usually good or bad ,no in between.
Did you do away with the thermostat on the pot? If not, that thermostat on the pot may not be allowing you to go above the 750 degrees. If still on the pot turn it all the way up.
Does your PID have a light to indicate output to the solid state relay? If that light stays on and the pot does not get hotter it is the thermostat on the pot.

[centershot]

OK, first, I bypassed the PID and plugged the pot into the wall receptacle. Forty five minutes later I had molten lead with a nice golden sheen on top. The power coed wasn't even warm. At this point, I started the PID just to check temperature, leaving the pot plugged into the wall. In a few seconds it read 790*, and stayed there, fluttering a bit up and down. I then plugged the pot back into the PID.The output light glowed steadily, so power was flowing to the SSR. I pressed the auto-tune button wondering if that might help. The manual said that sometimes it might be necessary to auto-tune if the unit had been in service for a long time. It didn'thelp. I let it run for about ten minutes, fluxed the pot, put the ladle in to pre-heat and dipped the corner of my mould into the melt. Temp dropped to 640* and stayed roughly there. My set point was 830, I'm casting pure lead (known pure). After lubing the mould I began casting, getting good results right off the bat. Temp still insisted the melt was 640* and I know from experience that can't be true! I ran about 30 pours and shut down the PID and unplugged the pot from it. WOW, was that plug HOT! All kinds of power flowing through here! The output light never flickered. I continued to cast for an hour with the pot plugged into the wall receptacle and all went well. At this point I'm thinking the thermocouple is *****. I was going to check voltage but the battery in my multimeter was dead. I'll head to Walmart this weekend and get one, but I'm pretty sure I'm going to need a new thermocouple. Thank you for all your help with this, guys, it is appreciated!

[Mal Paso]

Replace the HOT PLUG or socket. Plugs should not get hot, that's resistance where there should be none.

[jsizemore]

If you plugged the pot into the wall receptacle and it came to temp then most likely it's fine. If it was hot as heck when plugged into the PID socket, I'd be suspicious of the socket. Does the PID power output use a power cord female end?

If the pot cord doesn't receive adequate current and get the lead hot enough then the thermocouple is only seeing low temp and isn't the culprit.

[Rickf1985]

If you bought this unit from Hatch I suggest you call or message him and refer him to this thread or tell him what is happening and I am sure he will set it straight for you. Especially if it is part of his equipment. We can all guess but he is the one that builds this stuff every day.

[centershot]

My bad! I actually bought this kit from JConn, not Hatch. I edited my post to reflect that.

In answer to jsizemore's question, no, it isny a power cord female end. See photos. I'll pick up a new one on Monday from the electrical supply, or maybe I can find one at Home Depot tomorrow.

Attachment 304290Attachment 304291

In the first pic, the socket on the upper left corner is where the pot plugs in. In the second pic, again the upper left, is the pot connection. Shouldn't be too hard to source?

[jsizemore]

See that light colored powder around the right blade slot of the female socket? That's a sure sign of burnt crispy contact. That looks like a snap in outlet. Seen a few at Home Depot but not at Lowes. Home Depot used to carry Eagle but now carry consumer grade Hubell (?). Take a close look at you plug on your lead pot cord. Could be it needs some attention too. I changed out the cord on the Lee pot I used to use with an appliance cord with a ground. They're good for adding a short extension (6') to your freezer, refrigerator or window AC unit. They'll survive one of those appliances on an extended compressor overload situation when the power goes down and comes back on. I think you've found your problem. Good Luck.