Lee Pro 4-20 gets too hot

[hogstad7]

I have bought a brand new Lee Pro 4-20 furnace.
First time I used it, I sat the thermostat on "6" and waited.
The lead melted and the temp was still rising, so I sat it on "3". My lyman thermometer showed 900*f.

I tried my furnace again today. I sat it on the lowest setting. It reached 850*f before I plugged it out.

Is my furnace broken or am I just stupid?

[montana_charlie]

The lead melted and the temp was still rising, so I sat it on "3". My lyman thermometer showed 900*f.
I tried my furnace again today. I sat it on the lowest setting. It reached 850*f before I plugged it out.
Is my furnace broken or am I just stupid?
Just to cover all possibilities, find some way to check your thermometer.

a.) Note the reading when it is in water that just reaches boiling point.
b.) Compare it with another thermometer in a single pot of lead.
( mail it to someone to be compared with another ... I would do it for you )

Since the pot is new, you should be able to return it if the thermostat is not adjusted properly.

CM

[hogstad7]

I don't think the thermometer is broken, but I will check it.
The lead got so hot that it showed various colors and it was some fumes.

I will take it back to the shop when it opens after the holidays.

[Frozone]

Two possibilities,
The control is bad, or it's wired wrong. The first is the most likely.
Either way, since it's new, take it back.

OR you could buy a PID controller from me ;-)

[Gisli]

I also have a new Lee Pro 4-20 furnace, and the same happened to me. The thermostat is not working.
It didn´t matter to me, because I was going to wire the pot for my PID controller anyway.

[bosterr]

!+ on what Frozone said. I consider a PID an essential piece of equipment. Had I not already built one, I would have bought one of Frozone's. He's certainly the guru on these things (IMHO).

[Mal Paso]

PID

Lee uses a ($10 retail) Infinite Switch and no two are exactly the same. Lyman and RCBS have Thermostats but PID is superior.

[jethunter]

I have the same pot, it runs over 750F with the dial set on 4, and under 700 set at 3.5. The markings are not meant to to be calibrations, they are a reference only.

[hogstad7]

I have returned the pot 3 times now, but the store was out of stock last time I was there. They are awaiting new pots from Lee soon, so I hope that is a better batch. I know PID is much better, but I refuse to buy a new pot with defects.

[dromia]

I have returned the pot 3 times now, but the store was out of stock last time I was there. They are awaiting new pots from Lee soon, so I hope that is a better batch. I know PID is much better, but I refuse to buy a new pot with defects.

Absolutely, but when you do get a pot that works then I'd wholeheartedly recommend adding a PID controller.

[Frozone]

I have returned the pot 3 times now........

So you got a replacement pot each of those 3 times and Each STILL ran hot??

Contact LEE directly - I'd bet they'll warranty it themselves.

<edit>
I just thought of something:

I wonder if you have a 110V control in that pot?
Norway is 240V isn't it?

The 'infinite control' measures current passed through it.
The difference is very significant.

You need this part #EM2730
</edit>

[hogstad7]

Yes, Norway is 220-240V.
All three pots reached 900*f on lowest setting.
They had a metal handle and not the regular wood.

The pots were on backorder on the last shipment from Lee to my local store, so I hope they will be in stock on the next shipment in 2 weeks.

Is it possible to see if it is a 110V or 220V control?

[Frozone]

Not without disassemble, and I don't know if there is a part number on the control itself.
But that IS the problem, I'm sure of it.

A 220V pot uses half the amperage of a 110V.
The control is a rather low valued resistor, that means it reads 'Power', and power is the current squared.
The control works by heating up as current passes through it, after it gets to a certain temp (adjusted by the knob) it trips out until it cools down.
Half the current means the square root of the normal heat generated, the control never gets anywhere near it's trip value, even on it's lowest setting.

Your supplier ordered the wrong item, Or LEE shipped the wrong item, Or some overpaid and under qualified dipstick installed the wrong part.



I always replace that little button of wood with a 3/4" diameter x 2" long hardwood dowel anyway, it lets me keep a little farther from the hot stuff.

[bradh]

Not to be a smart **** but when I went to school power is not the current squared. Voltage = E and current = I.
Power P = EI. Voltage in volts and current in amps then power = watts.

[Frozone]

That's one way to calculate power, I² is another.

Technically it's P=I²R. Or you can use P= V²R too.

You studied electricity but not algebra ;-) http://www.physicsclassroom.com/class/circuits/u9l3d.cfm

Wattage is P = V x I,
but what is Voltage? V=IxR right?
So P=(IxR) x I ► P= I x I x R ► P= I² R


The value of R in the infinite control is small (~ 1 is common) and can be safely ignored in this case.

I will now dwell on the Infinite Control itself.

The Infinite Control consists of a Bimetallic strip (http://en.wikipedia.org/wiki/Bimetallic_strip) that is heated by the current that flows through it.
At one end of the strip is a power contact similar to what is in a relay.
As current flows and the Bimetal heats up, it flexes and pulls away from the opposite relay contact breaking the circuit.
The bimetal now begins to cool and will eventually make contact again and begin the cycle over.
The control knob pushes the non bimetal side of the relay contact closer or farther from the mid point of the bimetals flex range requiring the strip get hotter or cooler before the breaking contact.
Example:
Lets say the Bimetal is on the bottom of the 2 strips and flexes down when heated.
The control will (when set for more heat) push the top contact down towards the Bimetal.
This require the Bimetal to flow more current over time (or stay on longer) and get hotter before it has flexed enough to break the circuit. the same setting means the Bimetal doesn't have to cool as much before make contact again. The result is the power is on longer.
Of course the opposite applies when the upper contact is raised.

[hogstad7]

Both the pot and box is marked 220V. It is also without the plug, so all indicates that a jerk at Lee can't do his job.

Edit: the switch is marked 6,7A/120V AC.

[Frozone]

.....Edit: the switch is marked 6,7A/120V AC.

AH, It's hard to be humble when your as good as I am ;-)

[hogstad7]

I'm not sure what you mean...?

[Frozone]

don't worry about it - lost in the translation likely.

[tomme boy]

His head is Swelling up! :mrgreen:

[hogstad7]

Would the control I need be marked with something like 3,35A/220V AC?

[Frozone]

It likely would, BTW I posted the LEE part number in an earlier post.

[hogstad7]

Yes, I saw it. Thanks for the help. Good to know what the problem with the pots were. I will wait for the new pots to arrive in mid february. It is way too cold to cast outside now anyway, -1*f now.

[Bouv]

It is also without the plug, so all indicates that a jerk at Lee can't do his job.


Last year I bought a Lee Pro 4-20, it also comes without a plug. From several dealers the pots are available with a plug, but more expensive! The difference is, the cheaper pot, as I bought, comes without a plug, because it has no CE marking. This marking is required for many products in the EU Member States and the EFTA countries Iceland, Liechtenstein and Norway.
My Pot works out of the box, but a PID controller is a good addition.

[Frozone]

The LEE 220V unit does not come from the factory with a plug installed.
That is because it can be used on US 220V or Any of the other countries around the world - something like 6 different plug styles.
The odds are, that If it came with one , You would just have to cut it off and put your own countries on anyway.

[hogstad7]

All Lee pots sold here in Norway comes without the plug.
What I meant earlier is that all parts except the control is correct on my pot.

[hunter74]

I also have the same problem as my fellow countryman. I also have a broken Lee 10 lbs pot sitting in my garage, but when it worked, it didn't get too hot so I guess it had the right part to set the temp right. So, can I use the part from the 10 lbs Lee pot or does this not work in the 20 lbs pot? If I could use it I don't have to order a new one from Lee. The shipping and handeling to Norway seems kind of steep.

Thanks

[Frozone]

I'm afraid you can't use the #10 control in a #20 pot.
The current requirements are different.

As weird as it seems, you could 'likely' use the 20# 220V control in a 10# 110V pot, and the other way around.

But that doesn't help your problem.

I know what you mean about the shipping, IIRC I shipped ~2 lbs to Norway for ~ $45

[Norbrat]

I pulled the top off my 220V pot and this is the control.

http://farm9.staticflickr.com/8324/8442946400_05ce690ffb_c.jpg (http://www.flickr.com/photos/11260137@N07/8442946400/)

The pot is about 10 years old, so not sure if the new ones would have the same codes.

Hunter74, if your pot is dead, it is most likely just the element. That shouldn't be too expensive to mail out to you.

[hunter74]

Thanks. My pot isn't dead but I guess I have the wrong part in my pot and I have the one for 110v. I've guessed this after reading this and other posts on a different forum, but I'm not sure. The problem is that the pot is on MIN, the lowest setting, and the temp on the pot maxes out on approx 950-1000F, regardless of what setting the rheostat is on. The only way to control the temp is to pull the plug on it and it's a PITA to be frank. The pot was like this new so I could return it but I would rather fix it myself if it isen't too much of a hassel. Many of the Lee pots for 220V does have this problem so it's a fairly known problem so if I return it I may also get a new one with the same problem.

I'll open it tomorow and se if I could understand something when looking at the part in the post abowe. If it only could be as simple as to use the part from my 10 lbs broken pot.....but as Frozone said that does not likely gonna work.

[Norbrat]

<edit>
You need this part #EM2730
</edit>

Just had a look at the parts list at leeprecision.com

The "thermostat" for the Pro 4 20lb 220V is shown as EM1133, but it is described as "Thermostat 110V". Let's hope that's a Lee typo!

For the 110V model, it's shown as EL3466

For production pot (10lb model) 110V they show 2 different part no's: 90093 & EM1133.

And for production pot 220V also 2 no's: 90094 & EM2730

I reckon send Lee an email, and based on their reputation for customer service, they will most likely send you a thermostat in the mail for free.

[hunter74]

Today I opened up my Pro4-20 and took a look on the "thermostat". It had 6.7A/120V printed on it so it's clearly the wrong one for my 220V pot. Guess I should mail Lee and ask if they could send me the right one. On their web page they say they charge a 15 dollar handling fee for international customers + shipping cost (+customs and 25% tax on all of it in Norway) so I guess it all ads up to the 9 dollar part before I have it in my hands. But it's free to ask! Thank you for all the advice! This is a great forum! You'll hear how it goes!

[hunter74]

Got a replay from Lee Customer support and got even more confused. Anyone understanding what he's talking about, I don't ? What "points"? Where are they lockated?

"Mr. Bakke,

That is the correct thermostat, as thermostats are not voltage specific, but simply open and close a set of points, based on temperature. If you look at these points, they are probably welded shut, if you are constantly heating.

Thanks,

Andy"

[Frozone]

He's full of *&^%.

The 'points' he refers to are the contacts at the free end of the flat metal strips.
Small, round and facing each other. They look like little silver hockey pucks.
They open and close as the control works.
Simply gently pull 'down' on the bottom strip and see if they open.

I was going to download a pix from LEE and add arrows, but LEE's site is incredibly slow today, and the CS line is constantly busy.

Well I finally contacted LEE customer service.
They want the pot back so they can see for themselves.
They won't pay the return shipping either.

'Peter' didn't even know what an Infinite Control is..

[hunter74]

Thanks, sending the Pot to Lee and pay shipping is out of the question. I'll eyball the thermostat tomorow and see if i could get it to work. Another posibility is to buy a new one from Midway Norway. I mailed them today and they assured me that this one would fit. http://www.midway.no/epages/MidwayNorge.sf/no_NO/?ObjectPath=/Shops/MidwayNorge/Products/516277

Frozone...how much for your PID including shipping to Norway? If I don't get this to work I might order one.....guess I might do anyway, but since I'm quite new to the casting game I'm learning somthing everyday and I can't afford all the gear that's "nice to have" all at once, if you know what I mean :)

[Frozone]

That midway part is a good bet, at least They will warrant it, AND get on LEE's case if it isn't the right part.

Shipping is the bugger, IIRC ~ $48US, and that doesn't include duties, if any.
The unit is $160 /w thermocouple.

[hunter74]

Today I took my pot apart again and eyeballed the thermostat some more. The reason for the "full throttle" on the thermostat was that the contact points were welded together. Anyway it was not only to pry them from each other because when I did that it didn't heat op at all. I was about to give it up but after a little tinkering and bending of the bimetal strip and got the feel of it it finally did work! It had to be bent just right ! I haven't tried to cast with it but it just looks like it works and it holds the temp at about 700F at setting 5.

Guess it sometimes pays off to be stubborn (and dirt cheap) :) Thanks for good advice!

[hogstad7]

I have now fixed my pot. I followed the description by "hunter74".

Thanks for the help guys!

[DaveInFloweryBranchGA]

Hunter74,

You are talking like a typical boolit caster and it sounds like you are well on your way now. Congratulations on repairing/adjusting your pot's controls.

[MT Chambers]

L+E=0
L is Lee
E is Electricity