Rewiring a popcorn Machine

[Ramper]

We picked up a popcorn machine for FREE off of CL. The kettle wiring was all burned out. I ordered High Temp wire and attempted to rewire it. I plug it in and it immediately blows the GFCI as soon as I flip the switch. The wire size is OK (12 gauge and only 9.4 amps)

I have attached a wiring diagram. It uses a twist plug. I connected the wire that is grounded to the kettle frame to the green screw. The wire to the thermostat to the silver screw and the wire directly to the heating element to the gold screw. I assume (in my limited electric knowledge) that the gold and silver connections could be reversed.

The light and motor work fine so there is power running to the unit. The kettle is all that is not working.

THANKS FOR ANY SUGGESTIONS. I have already spent $30 in wire for a free machine.

 

[nehog]

Just a WAG, but I suspect that your element has failed and is leaking current to ground. Or the motor is bad. Try disconnecting both sides of the motor and seeing if it trips the GFCI. If it still trips, disconnect both sides of the element and do the same test.

Likely the element, and that's what burned the wires.

 

[Ramper]

There is no motor in the kettle portion. If I unplug the kettle the motor (that stirs the popcorn) works fine. Is there a way to test the heating element?

Here is a picture of the bottom of the kettle. The power come into the top screw on the heating element and then the front screw on the thermostat. the ground wire is grounded to the outer "kettle" (the part that this sits inside of)

There other is a parts diagram. The heater is labeled at 1000W

 

[Ramper]

Also what is a WAG?

 

[jerryd68]

I would take a meter and check between the sliver terminal and ground as well as between the gold terminal and ground. I would also bet that the heating element has shorted out. Check resistance across the heating element.

 

[Milton Shaw]

WAG is Wild A$$ Guess. At least that's what it always has been around here. Sounds like a shorted element in the pan. Check ohm between element and pan, I suspect you will find some ohms which is what is tripping the GCFI.

 

[jaymz1967]

WAG=Wild *** Guess Maybe

 

[Warrenator]

Get a multimeter, set it to ohms (resistance) there should be some low resistance between the in and the out of the element (I dunno, 10 - 200 ohms or so) and some very high resistance between ground (the kettle itself and/or the ground wire (like 10,000 ohms.) If the resistance between the in and the out of the heating element is very high you have a broken element. If the resistance between the element and ground is low, the insulation is broken down and you have a short. In either case a new element is required, probably cannot repair that one as they are made out of a certain resistive kind of wire that would be hard to duplicate unless you are A_PMech.

WAG is a wild assed guess.

 

[Ramper]

I will check out the element. The replacement cost is around $100, so it might not happen.

 

[LEVE]

Did you try the popper in a non-GFCI protected outlet? It may be that the GFCI is too sensitive. It is normal for continuous running motors, such as pumps, to sometimes have small electrical fluctuations. Sensitive GFCI’s may detect this and falsely trip. You may want to try a new GFCI, or a different brand of GFCI.

 

[nehog]

There is no motor in the kettle portion. If I unplug the kettle the motor (that stirs the popcorn) works fine. Is there a way to test the heating element?...

You unplug the motor and it doesn't trip the GFCI? If yes (you say that but I'm not convinced you mean it! ) the motor is the problem.

If you are not saying that, then disconnect the element and plug it in and turn it on. Does the GFCI trip? No: element is bad. Yes: Wiring/connector is bad.

WAG: Yes, Wild ***'ed Guess.

 

[Ramper]

I tested the heating element and it showed continuity and 14.8 ohms.

As far as the "motor", that is separate and not part of part of the kettle circuit. With the kettle circuit off at the switch the motor does not run (and it is not suppose to run). With the kettle unplugged, when I switch on the kettle the motor turned just fine.

I am confident that the issue is with the kettle elements:

• Heater
• Thermostat
• Ground
• Wiring
• Plug
• receptacle

 

[nehog]

I tested the heating element and it showed continuity and 14.8 ohms...

OK, measure continuity of the element to ground and report that.

 

[Ramper]

There is NO continuity between the element and the ground. I have it rewired again and will try it on a non-GFCI circuit. I have continuity from the two "live" prongs on the plug and NO continuity between either of the "live" prongs and the ground prong. I manual moved the bi-metal thermostat and it did cut the continuity between the to posts of the element.

 

[Ramper]

I just took it all apart and the bottom heating element does not have continuity in it. It is just a wire that must heat up somehow and warm the bottom of the unit. At this point, I am jut going to order up some more high temp wire and rewire the entire unit. As for the bottom element, I am not sure what I will use as a heat source.

 

[LEVE]

I just took it all apart and the bottom heating element does not have continuity in it

Are you sure you're reading that right? Is that a "resistive ring", or more like an oven element? In any case you should be able to pull it and apply 120 volts to it, directly, to see if it will heat. That's what I'd do to avoid ordering a part that may not be needed.

 

[Ramper]

I have not ordered anything. It is a wire type heating element that was taped to the bottom side of the lower tray.

 

[Socophreak]

Make model? You can get resistive heating wire, but most use an actual heating element like your range.

Are you talking about the kettle element or the heating element of the cabinet? I would go through every component and test for resistance to ground. I would disconnect each component electrically to ensure the component is being measured properly.

Those terminals look pretty toast as well. Are those cleaned up?

 

[Ramper]

MPC-1A

I have all new high temperature terminals for the area under the kettle and new high temp 12 gauge wire.

The heating wire under the bottom does not concern me too much. I will test it tomorrow, but without continuity I am not hopeful that it will heat up.

I am planning on all new terminals in the top wiring tomorrow.

 

[Ramper]

With regard to the heating wire under the hopper:
I do not get continuity along the whole wire
I do get continuity between and about 3 inch section of the wire. All along the wire's length.

Is there some sort of build up to continuity?

 

[rlitman]

There is NO continuity between the element and the ground.

With regard to the heating wire under the hopper:
I do not get continuity along the whole wire
I do get continuity between and about 3 inch section of the wire. All along the wire's length.

Is there some sort of build up to continuity?

You need to be measuring resistance, not continuity. Measure the resistance between the coil and ground.

 

[Socophreak]

Ramper - Heating wire has a certain amount of resistance per foot. A meter typically won't beep after X amount of ohms resistance, you need to check resistance across and resistance to ground, ground being the metal around the element.

If you're disconnecting the element and the popper is working, It would be safe to assume the element has failed, if there are other components in that circuit you are disconnecting, you should probably isolate each part and re-test.

 

[Ramper]

Here is where I stand. I have rewired the unit and all seems to be fine except the kettle. The kettle has the following:

• Continuity throught the heating element
• 14.8 Ohms resistance for the heater (1000 Watts)
• Continuity through the thermostat
• Contunity through the lead wires to the heating element

Here is what I want to do: I want to send the unit to a GJ member that is more knowledgeable than me to rewire. I will send along ALL the parts and conduct any tests or take any pictures requested. I will send the unit along with some $$$ to send it back and some $$$ to buy some beer. ANYBODY UP FOR THE CHALLENGE?

 

[I Fixeded It]

Dude, don't give-up on this machine. Commercial poppers are worth $700 plus. I bought 2 JetStars 8oz for $100 at a hosp auction. Rebuilt one and enjoyed it for a yr then the heating element and thermostat went out. I got my parts and stupidly wired incorrect, forgot how to wire and now I'm having the same problem. Once your get it goin or poppin there's no comparison.

 

[MTW]

Suggestions:

First off do your testing on a non GFCI protected circuit. Heating elements normally leak some current to ground in normal operation. A regular GFCI receptacle will trip at 5mA of leakage. Heaters for pipes and vessels require GFCI protection of at least 30mA these are special and expensive. With the element directly attached to the grounded vessel there is sure to be some leakage and this is normal.

If the element is reading 14 ohms it is good. Moving or bending a nichrome wire element is not a good idea, it becomes brittle and oxidized due to the heat cycling. It may break if you fool with it too much, same go's for the terminal connections. Do not try to measure the resistance along its length, it is very oxidized and will give erroneous readings at best.

More likely your thermostat could be defective if it doesn't heat. These surface mount thermostats a very common in commercial cooking equipment. It may become erratic in operation if it has been heavily used. They are constructed of a bi-metal element with contacts on the end of the arms. The metal doses become fatigued over time. And the contacts could be worn.

While connected to a non GFCI circuit, test the voltage at the ends of the element. If it reads 120V it should be heating if it's good. If no voltage exists, then test between the input side of the thermostat and the other end of the element. If you have voltage then the thermostat is not conducting. If no voltage exists then you have a problem it the supply wiring/connector before the kettle.

A note about the wire and terminals. They should all be designed for high heat. Normal copper wire and copper ring terminals will fail after repeated heat cycling. The copper oxides badly and will crumble and burn under repeated hi temp use. High temp terminals are usually made of steel with a nickel plating. Hi temp wire is a special alloy with special insulation, silicone insulation covered with a fiberglass braid, trade type SRML If you have a company that services restaurant equipment in your area you could source some of the material from them.

 

[Charles (in GA)]

I would think the thermostat would be intended to interrupt the HOT and not the NEUTRAL. You say you have the wire off the SILVER screw (which is the NEUTRAL) going to the thermostat, and the wire off the BRASS screw (the HOT) to the element directly. You might try reversing the wires connected to the SILVER and BRASS screws so the BRASS (HOT) supplies the thermostat.

Might not fix it, but won't hurt either.

Charles

 

[nehog]

I think the OP gave up on it. He was going to send it to me for some testing and diagnostics but never did, and the subject dropped.

 

[Ramper]

Actually the OP didn't give up, but he teaches school and coaches football so he is very busy right now. In fact right now he is trying to remember the heating element part number to order one as his wife wants popcorn for a kid's b-day party in a month

BTW, I am the OP

 

[daleeper]

My popper had an electrical terminal block located on top under the top hood that was absolutely filthy. First thing I did was get it cleaned up. Could be some stray voltage going on in the wiring block if you have one. These things are harder to clean than they are to work on.

 

[Ramper]

Once football ends, I plan to tear down the entire unit and rewire it. I will probably just install a new heater (about $100) as I got the unit for free.

 

[Ramper]

Well, I rewired the entire unit with high temp wire and put it back together. It works PERFECTLY on a non-gfci circuit and it works MOST TIMES on a on a gfci circuit. The wattage drawn is right on the mark. I am fairly confident using the unit now. I am still a little concern about GFCI, but I am thinking that the two heaters (cable heater on the bottom and the heater ring on the kettle) are just not meant to be used on GFCI. I have read LOTS of information both here and on the internet (so it must be true) that heater elements and GFCI do not always work well together.

 

[laser3kw]

good to hear!
As soon as I saw the post, I was wondering how you made out.

 

[LS6 Tommy]

I tested the heating element and it showed continuity and 14.8 ohms.

Impedance for a 1000w 120VAC heating element should be roughly 14.4 ohms, so something is "leaking" current causing the GFCI trips. Strip heaters can do that.

Tommy

 

[nehog]

Were this mine, and I was comfortable that the ground was good, I'd have no problems using it on a non-GFCI outlet. Glad you got it working!