Project - PID on Lee Pro 4 20 furnace

[Frozone]

Heck of a deal. Here is one that you don't even have to cut a wire to build and darn $130

[USAFrox]

Well, poop. Wish I had seen that before ordering all my stuff. I still will have to pick up a terminal strip and a couple other bits and have already spent more than the $130 that your kit costs. Live and learn, I guess.

[meeesterpaul]

Could parts from an old stove work?
I cut up an electric stove to use the cooktop to make a smelter. I didn't think to save the oven thermocouple but I may have the oven controls still.

[meeesterpaul]

I have the same thought. Have you heard about using stove parts?

[10x]

I have the same thought. Have you heard about using stove parts?

I have thought about it but the local mall - uhh - dump does has not had any stoves in with PID controllers. All left to date are older style.
I suspect the PID controller on a stove may or not be suitable. To find out obtain a PID from a stove, take the name and model number of the PID and download the spec sheet for that PID. Parts from appliance part places are sometimes very expensive.

[meeesterpaul]

I'm going to pick through the wiring harness and see what I have. It would be nice if it works.

[JonB_in_Glencoe]

I have poo pooed the idea of a PID. Just too much $$$ for a $60 lead furnace. But I finally changed my mind when I found some cheap parts from Hong Kong. They should arrive in a couple weeks, if the boat don't sink. I'm thinking I gonna be able to bubba up a $26 PID with a $5 thermocouple with other parts I have stashed in my attic that originated from various trashcans over the years. The first thing I dug out of the attic was a old USA made SSR in a cage enclosure, output rated 6amp@240v...(so that should translate to 12amp@120v should be adequate for a Lee pot that pulls 5.5amp)

[Mal Paso]

I have poo pooed the idea of a PID. Just too much $$$ for a $60 lead furnace. But I finally changed my mind when I found some cheap parts from Hong Kong. They should arrive in a couple weeks, if the boat don't sink. I'm thinking I gonna be able to bubba up a $26 PID with a $5 thermocouple with other parts I have stashed in my attic that originated from various trashcans over the years. The first thing I dug out of the attic was a old USA made SSR in a cage enclosure, output rated 6amp@240v...(so that should translate to 12amp@120v should be adequate for a Lee pot that pulls 5.5amp)

Amperage ratings are usually the same regardless of voltage. If 6 amp is the max strap it to a chunk of metal with heat sink paste.

On the plus side, it's a resistive load and will not spike. Your outlet voltage would have to be abnormally high for the Lee to go over 6 amps.

[ETXShooter]

Amperage ratings are usually the same regardless of voltage. If 6 amp is the max strap it to a chunk of metal with heat sink paste.

On the plus side, it's a resistive load and will not spike. Your outlet voltage would have to be abnormally high for the Lee to go over 6 amps.

When I built mine I called Lee and was told their Pro 4-20 pot pulled 6.3 Amps both inrush and steady state. According to their data the 700 Watt rating is for 110V which makes the math come out about right. My voltage runs right at 119V so I figure I'm probably pulling around 6.7 Amps. Maybe I'll actually measure it one of these days but that's the number I used for design.

[Mal Paso]

My lee 4-20s measure 20 and 20.5 ohms. 20 ohms is exactly 6 amps at 120 volts. 20.5 ohms is less. YMMV

If it's Old USA Made it should do what the boiler plate says but normal electrical practice is 80% of max.

[Bogone]

Bump !

[JonB_in_Glencoe]

Amperage ratings are usually the same regardless of voltage. If 6 amp is the max strap it to a chunk of metal with heat sink paste.

On the plus side, it's a resistive load and will not spike. Your outlet voltage would have to be abnormally high for the Lee to go over 6 amps.

Dang, I was thinking how a load reacts to voltage change. Shucks, yeah that's right, to the switching device current is current. I doubt that'll cut the mustard. I got the PID and the thermocouple last week. I suppose I need to look for a higher rated SSR.

[Deedurt]

I have read through the manual a few times and have now spent a couple of hours trouble shooting and am still coming up empty handed. I have wired everything according to the schematics but am not getting any DC voltage on the PID output to the SSR. The OUT LED is lit up showing me that the PID thinks it is sending the signal voltage to the SSR. Am I supposed to be making a change in the settings for SSR control? Can anyone tell me what might be happening or better yet how to fix my problem?

Disclaimer: I am electronically challenged.

Thanks in advance

Auberins PID, 25 A SSR, K TC

[John Boy]

We discussed PID's over on the ASSRA forum and here's a PID for less than 30 bucks - thanks to author, Chickenthief:
Controller ... http://dx.com/p/digital-temperature-controller-66334
SSR ... http://dx.com/p/ssr-10va-solid-state...-silver-230992

[el34]

One possibility is that you have a PID controller with a relay output (simple switch contacts) instead of a voltage output. If it's a Mypin with RNR in its name, the first R indicates a relay output. SNR would indicate its output is a voltage intended to fire the SSR.

If this is your problem there are a couple of ways to fix it, not too hard-

1/ find 5-30v dc or add a wallwart power supply. Hook the neg to the - on your SSR control input, hook *** to one of the PID output terminals and the + of your SSR control input to the other PID output terminal. The PID relay will switch the dc voltage on/off to the SSR.

2/ Pull the PID guts gently out of the case and make a small mod to one of the pc boards. PM me and I'll give you details, I might have a pic or two.

#1 is probably simpler but you have to add a small power supply, like a charger or one like what comes with small electronic things. You'd have to connect your AC input to the power supply plugin blades.

Or get a PID with an output intended to control an SSR.

[el34]

We discussed PID's over on the ASSRA forum and here's a PID for less than 30 bucks - thanks to author, Chickenthief:
Controller ... http://dx.com/p/digital-temperature-controller-66334
SSR ... http://dx.com/p/ssr-10va-solid-state...-silver-230992

Johnboy, something doesn't compute- the schematic shows the PID output directly connected to the SSR implying the controller's output is a DC voltage suitable for SSR control. But the picture of the controller says OUTPUT = RELAY on its label, and the terminal markings on the website pic shows terminals 5-6-7 are just internal relay contacts. The SSR control needs a dc voltage coming from somewhere, ???

[Frozone]

You want to avoid those REX 100 controllers too. They do not have a stellar reputation.

[Deedurt]

Ahh, you guys are smart, that's why I like this forum. I just checked the packing slip and saw that I ordered a relay output PID. Does anybody have any experience with returning items to Auberins?

Thanks for the help guys

[Lee]

Door #1. Buy a Wally Mart WallWart, hook it up as described above. Done. (Thanks el34 !!)

Without disparaging rain makers and snake oil salesmen. if you just gotta have it right now, well then price is no object. If you are willing to be patient, well then as an example, I've got 4 here chugging along for much less than the price I've seen bandied about for one. Patience is a virtue. E-bay is not always evil....

Brand names? I've seen my share of Lexus supercars, and Jeep 4WD's cleaning ditches each winter. At this point in time I doubt you can even buy a toothpick made in America anymore.
I just buy the cheapest I can get. If it works and lasts a reasonable amount of time ..... WooHoo. If not, THEN I worry about taking a chance on a Cadillac$$ part for a Chevy, possibly outsourced from the same overseas.............

Rant off!

[bpratl]

bpratl
I'll take a WAG and say the problem is caused by the 'banana' plugs you are using to connect the TC to the PID. Or with the wiring behind the plugs.
If you connect the immersion TCs to the PID, using the same banana style connection, do you get the same ~50° error?

Frozone, you are 150% correct. This week I finally made time to replace the banana plugs with the proper TC connectors and to my amazement boiling water read 272 deg because I had a -60 deg offset set to compensate for the banana plugs. When I reset the offset to zero boiling water read 212 on three different TC's. Thanks again...you definitely know your PID's.