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Old 12-02-2012, 07:27 AM   #1
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Line and Load


I have installed a rheostat on my electrical smoker, there are two wires on the rheostat, line and load, one is red the other is black. I plan to buy an element that just plugs in and runs constantly. I want to be able to adjust the heat with the rheostat instead of adjusting the heat in the smoker by the vents.

I smoke slow and it takes a long time up to 18-22 hours sometimes. It gets cold at night and the temps inside the smoker will cool off more at night so I would have to reset the vents to keep more heat in, I don't want to have to do that, I want to set the temps and be done with it.

I plan to cut the hot side of the element cord and connect to the rheostat. Which is line and which is load, the wires are black and one is red. The black is on the bottom of the rheostat and the red on top.

The element is 1,500 watt 110 volt the rheostat is rated at 22 Amps 220 volt, so I think I am safe here.

Another question, can a thermocoupling be used to gauge the heat, if so would it hook in on the line side or load side of the rheostat?

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Old 12-02-2012, 07:32 AM   #2
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Line and Load


Line is the wire (or wires hot and neutral) from power source, say, coming in from the power cord.

Load is the wire (or wires hot and neutral) going to the heating element.

Rheostats, switches, dimmers, etc. are always installed in the hot path, or sometimes in both hot and neutral for isolation purposes where the same switch unit (2 pole) acts on both. Never in the neutral path only.

You can buy thermostat switches to control the full (120 or 240 volt) line voltage. Some have a bulb sensor that can be as large as but usually smaller than an AAA battery with a wire (actually a thin tube) connected to the switch body that must never be bent sharply or kinked or rebent frequently, letting you put the sensor through a hole into the smoking chamber. Be sure the one you buy can handle the temperatures involved, otherwise it could explode like an overheated glass thermometer. And it has to handle the amperes of the heating element.

This switch usually has two wires, sometimes labeled line and load, but usually unlabeled and interchangeable. You can connect this switch either before or after a rheostat. That is, either on the rheostat's line side or the rheostat's load side. Do not put the thermostat switch in the neutral path just because the hot path has already been broken by the rheostat.

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Last edited by AllanJ; 12-02-2012 at 07:52 AM.
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Old 12-02-2012, 07:58 AM   #3
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Line and Load


Quote:
Originally Posted by AllanJ View Post
Line is the wire (or wires hot and neutral) from power source, say, coming in from the power cord.

Load is the wire (or wires hot and neutral) going to the heating element.

Rheostats, switches, dimmers, etc. are always installed in the hot path, or sometimes in both hot and neutral for isolation purposes where the same switch unit (2 pole) acts on both. Never in the neutral path only.

You can buy thermostat switches to control the full (120 or 240 volt) line voltage. Some have a bulb sensor that can be as large as but usually smaller than an AAA battery with a wire (actually a thin tube) connected to the switch body that must never be bent sharply or kinked or rebent frequently, letting you put the sensor through a hole into the smoking chamber. Be sure the one you buy can handle the temperatures involved, otherwise it could explode like an overheated glass thermometer. And it has to handle the amperes of the heating element.

This switch usually has two wires, sometimes labeled line and load, but usually unlabeled and interchangeable. You can connect this switch either before or after a rheostat. That is, either on the rheostat's line side or the rheostat's load side. Do not put the thermostat switch in the neutral path just because the hot path has already been broken by the rheostat.

Thanks a ton Allen, I really do appreciate you explaining this to me, this is just what I am looking for. Thanks again.
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Old 12-03-2012, 12:32 AM   #4
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Line and Load


More questions, I want to do some smoking before Christmas but if I order a new element it won't get here in time. I have another element but don't know which wires are which. I am posting a couple of pictures below. Which colored wires that go into the element are hot wires, and which ones are common and which one is ground. This is a 220 unit out of an old Jenn Air griddle and I more than likely will only use one side of it.

Anyone have any idea what wires are hot and common and ground in the third picture?
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Line and Load-shop-001.jpg   Line and Load-shop-005.jpg   Line and Load-shop-003.jpg  
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Old 12-03-2012, 07:31 AM   #5
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Line and Load


I can't tell from the pictures. Can you post the make and model of the jenair unit. There might be a drawing online that will give the info. The drawing could even be on the unit.
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Old 12-03-2012, 09:49 AM   #6
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Line and Load


Joe, that unit has been gone for a long time, this is all I have left of it. The last picture is the wire in a shielded flex conduit. Maybe you can tell me this, the heating elements have two wires to them. Is that just a 110 v hot wire and common or are there resisters or something else. If I knew that, I could charge up one side and run a common to the other and see if that would work but I am allergic to electricity, it hurts.
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Old 12-03-2012, 10:32 AM   #7
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Line and Load


You can have a multipart element where different combinations of connections are made for low, medium, and high heat.

For an element with just two wires, hot and common are interchangeable.

The ground wire is attached to the framework of the element.

Using an ohmmeter (or the ohms function of a multimeter) you should measure no continuity (infinite number ohms) from the ground wire to any of the other wires. If you get continuity (not infinite ohms) between the framework and any of the element wires, that means the element is shorted to ground (has a ground fault) and should be discarded.

You should measure just a few ohms between the wires that go to any one particular element. If one element has three or four wires, the number of ohms between the various combinations of two wires at a time (the meter has just two probes) will let you know which wires are at the ends and which wire(s) are in the middle of the element. Normally you can put 120 volts on any two wires.

You should measure no continuity between wires that go to different elements in the same framework.

When measuring ohms or continuity, turn the power off and also at least one of the two places (screw, wire, etc.) must have been unhooked from all other wires, screws, etc. (Put labels on everything you take apart.)
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Last edited by AllanJ; 12-03-2012 at 10:38 AM.
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Old 12-03-2012, 11:18 AM   #8
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Line and Load


Quote:
Originally Posted by AllanJ View Post
You can have a multipart element where different combinations of connections are made for low, medium, and high heat.

For an element with just two wires, hot and common are interchangeable.

The ground wire is attached to the framework of the element.

Using an ohmmeter (or the ohms function of a multimeter) you should measure no continuity (infinite number ohms) from the ground wire to any of the other wires. If you get continuity (not infinite ohms) between the framework and any of the element wires, that means the element is shorted to ground (has a ground fault) and should be discarded.

You should measure just a few ohms between the wires that go to any one particular element. If one element has three or four wires, the number of ohms between the various combinations of two wires at a time (the meter has just two probes) will let you know which wires are at the ends and which wire(s) are in the middle of the element. Normally you can put 120 volts on any two wires.

You should measure no continuity between wires that go to different elements in the same framework.

When measuring ohms or continuity, turn the power off and also at least one of the two places (screw, wire, etc.) must have been unhooked from all other wires, screws, etc. (Put labels on everything you take apart.)
I may have a meter out in the shop, I will check to see. From what I understand, you are saying the element itself grounds when installed in the main unit, as the main unit is grounded, right? Then the two wires on one side are high and low, and the three wires on the other element are high medium and low, right?

If I installed this in my smoker I should be sure the smoker is grounded, I need to do that anyway. If I could figure out which wire was the high wire I could hook into that wire and control the temps through the rheostat, I think. Trying to find any information online or the Jenn Air site is like pulling teeth.
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Old 12-03-2012, 12:43 PM   #9
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Line and Load


If you look closely at the element it probably has stamped on it the wattage and voltage ratings. Then you will know if it is 120 or 240 volts.
Measure the resistance between all the wires. If there is connection between them all then one wire is common and the other wires are the different wattages. Are those controls from the Jenair or the smoker? If they are from the Jenair can you post a close up of the connection to the switches.
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Old 12-03-2012, 06:10 PM   #10
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Line and Load


I got out in the shop today and tore into the hook up in the first picture, the black, white and red wire prongs are tied together through a wielded bar, the yellow and blue are separate or individual. I found on the plate, which is very hard to see, that it is 220v 2400 watt.

I know some smokers have elements as low as 800 watts but I don't think 800 watts would work for me. I am not sure 1200 watts would work because it would take so long to recover when the door is opened. The smoker is, well here is a picture after I insulated it, not pretty but I wasn't trying for pretty.

My problem now is if I use the 220 element how will I use the rheostat as it only has two wires. I can't hook the common up to the rheostat, or can I? I know this unit works because I hooked it up straight and it heated up good.
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Old 12-03-2012, 07:58 PM   #11
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Line and Load


Typical designation of 3 wires coming from one element: common, low, and high. An element that takes 240 volts will of course have a "second low" and a "second high" if fed with 120 volts. If there are just two wires then there is only one heat output for 120 volts (and a different heat output if fed with 240 volts).

Another way of thinking about it is that the element draws X watts when you connect common and low and it draws (and outputs) Y watts when you connect common and high. If the other element is on at the same time it draws Z watts. So different combinations give different total watts (like X plus Z). So the dial can have lots of click stops for extra high, high, medium high, medium, medium low, etc.
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Old 12-03-2012, 09:11 PM   #12
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Line and Load


Quote:
Originally Posted by AllanJ View Post
Typical designation of 3 wires coming from one element: common, low, and high. An element that takes 240 volts will of course have a "second low" and a "second high" if fed with 120 volts. If there are just two wires then there is only one heat output for 120 volts (and a different heat output if fed with 240 volts).

Another way of thinking about it is that the element draws X watts when you connect common and low and it draws (and outputs) Y watts when you connect common and high. If the other element is on at the same time it draws Z watts. So different combinations give different total watts (like X plus Z). So the dial can have lots of click stops for extra high, high, medium high, medium, medium low, etc.
Allen, I really do appreciate you and Joe taking your time to help me out. This makes all the sense in the world, thanks a lot.

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