Heat Treat PID Control Wiring

  • Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
SMF is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

civilsmoker

Smoking Guru
Original poster
OTBS Member
★ Lifetime Premier ★
Jan 27, 2015
6,043
8,198
Idaho
Been enjoying some time away from work and have been working on my PID control box for my heat-treating oven. I found very good use for the new mini mill and milled the metal control box openings...... WOW where has this tool been all my life!

The control box layout plan is to have a main illuminated power switch (15A fuse), with a 2A fuse for the PID power and then have an illuminated switch for the power to the element as well as a limit switch with an indicator light for the element to indicate a "hot" element. Sticking a piece of steel in the oven with a "live" element is...... well not a good idea. Here is the control box face.
42F03C1E-3467-4DF0-B34E-ADAF822506C8.jpeg

Inside the control box....
68B29AB1-3C4F-4FA7-8D46-15C9BFE09BB1.jpeg


Here is my planned wiring diagram.....
DF6A4D4D-339B-4CD6-96EA-DB174C7D226A.jpeg

Note I am an engineer but not a EE or electrician by any means, so I thought I would have a little "internet qc" by those that have built PID smoking units to verify I don't have any diagram flaws. Note I did add a dashed N line as an alternate path to avoid doubling up on the terminal block screw. I am also running the LED L lead through the terminal block to avoid an inline splice.

Any input from the more experienced would be appreciated.......
 
  • Like
Reactions: JC in GB
Been enjoying some time away from work and have been working on my PID control box for my heat-treating oven. I found very good use for the new mini mill and milled the metal control box openings...... WOW where has this tool been all my life!

The control box layout plan is to have a main illuminated power switch (15A fuse), with a 2A fuse for the PID power and then have an illuminated switch for the power to the element as well as a limit switch with an indicator light for the element to indicate a "hot" element. Sticking a piece of steel in the oven with a "live" element is...... well not a good idea. Here is the control box face.
View attachment 652901
Inside the control box....
View attachment 652902

Here is my planned wiring diagram.....
View attachment 652900
Note I am an engineer but not a EE or electrician by any means, so I thought I would have a little "internet qc" by those that have built PID smoking units to verify I don't have any diagram flaws. Note I did add a dashed N line as an alternate path to avoid doubling up on the terminal block screw. I am also running the LED L lead through the terminal block to avoid an inline splice.

Any input from the more experienced would be appreciated.......
Nice work, it's all looking good!

Nothing is wrong with your design, in fact it is very good.
Just a heads up though. The rocker switches, fuse holders, and the outlet components have a high high chance of melting down on you.

How do I know this???? Been there and done that.
Unless you got really really hardcore non-cheap Chinese plastic crap, you can pretty much expect those components to not last too many months.

I got so fed up of all those components melting down on me, I changed my power switch to a 40 amp marine breaker switch.
I changed the female outlets to be female 16AWG outdoor extension cord ends that I cannibalized and used the dame type of plastic relief glands you are using to fasten them to the box.
I had to change to Humana Bussmann fuse holders but even those had some issues with quality.

So again, your design and ideas are good. Your components may fail. If/When that starts to happen you know what I did to work around it.

Also yeah having the right tools to work the project box is a huge bonus... I have a dremel rotary tool and a drill. Cutting rectangle/square holes is always a chore for me so I do as many round holes as I can and minimize the non-round holes and components lol :)

Let me know if this makes sense and ask any questions you have :)
 
Nice work, it's all looking good!

Nothing is wrong with your design, in fact it is very good.
Just a heads up though. The rocker switches, fuse holders, and the outlet components have a high high chance of melting down on you.

How do I know this???? Been there and done that.
Unless you got really really hardcore non-cheap Chinese plastic crap, you can pretty much expect those components to not last too many months.

I got so fed up of all those components melting down on me, I changed my power switch to a 40 amp marine breaker switch.
I changed the female outlets to be female 16AWG outdoor extension cord ends that I cannibalized and used the dame type of plastic relief glands you are using to fasten them to the box.
I had to change to Humana Bussmann fuse holders but even those had some issues with quality.

So again, your design and ideas are good. Your components may fail. If/When that starts to happen you know what I did to work around it.

Also yeah having the right tools to work the project box is a huge bonus... I have a dremel rotary tool and a drill. Cutting rectangle/square holes is always a chore for me so I do as many round holes as I can and minimize the non-round holes and components lol :)

Let me know if this makes sense and ask any questions you have :)
Thanks tallbm,

I got the rockers and one fuse holder from Aubers (both UL listed - 15 A) and the second fuse holder is a bussmann (15 A rated for the 2 A PID line) (was going to order the same UL listed one from Aubers, ie I messed up on my order and forgot about the 2 A holder).

I also got the UL listed SSR from Aubers vs the cheaper one as well.... The power cord will be a 12AWG outdoor rated and all the wire inside will be 12AWG 200C Silicone wire as well.

I thought about a circuit breaker vs the toggles but many of the knife guys are using the toggles and no reported issues. The rockers and fuse holder are the same ones that Aubers uses in their plug and play heat treat control box so I will have my fingers crossed.... but changing out to a breaker switch wouldn't be too difficult.

Thanks again for the response and heads up, I now know the weak links!

edit.....I may order the 30 A rated holder for the power line and then 30 A waterproof rockers (ie same shipping price from Aubers) and switch them out to keep the longevity......
 
Last edited:
Thanks tallbm,

I got the rockers and one fuse holder from Aubers (both UL listed - 15 A) and the second fuse holder is a bussmann (15 A rated for the 2 A PID line) (was going to order the same UL listed one from Aubers, ie I messed up on my order and forgot about the 2 A holder).

I also got the UL listed SSR from Aubers vs the cheaper one as well.... The power cord will be a 12AWG outdoor rated and all the wire inside will be 12AWG 200C Silicone wire as well.

I thought about a circuit breaker vs the toggles but many of the knife guys are using the toggles and no reported issues. The rockers and fuse holder are the same ones that Aubers uses in their plug and play heat treat control box so I will have my fingers crossed.... but changing out to a breaker switch wouldn't be too difficult.

Thanks again for the response and heads up, I now know the weak links!

edit.....I may order the 30 A rated holder for the power line and then 30 A waterproof rockers (ie same shipping price from Aubers) and switch them out to keep the longevity......
You did good getting the UL rated parts that Auber uses. That goes a loooooong way.
I burned up at least 3 female outlets, 3 fuse holders and 5 rocker switches I ordered on Amazon that came from China.

Safety rollout limit switches burn up a ton to but the Ceramic ones seem to be much better... if you ever have to replace one.

I think u are in good shape and have good plans should you need those other parts or want to switch some out. Your smoker will be kickin butt in no time with that PID controller! :D
 
  • Like
Reactions: civilsmoker
Just curious if you used a heat sync on the SSR ?
The heat sink is an external on the top, you can see it at top of the first pic. I didn’t want that heat inside the box so it’s rated for a 40 amp SSR…. Keeping that heat out of the box will prevent lots of issues with the electronics in the box…..
 
Last edited:
You did good getting the UL rated parts that Auber uses. That goes a loooooong way.
I burned up at least 3 female outlets, 3 fuse holders and 5 rocker switches I ordered on Amazon that came from China.

Safety rollout limit switches burn up a ton to but the Ceramic ones seem to be much better... if you ever have to replace one.

I think u are in good shape and have good plans should you need those other parts or want to switch some out. Your smoker will be kickin butt in no time with that PID controller! :D
Thanks, it’s actually going to be for a knife heat treating oven, ie so I can ramp heat to 1975 deg for stainless treating…..

There are lots of knife builders that have built these and their biggest suggestion was to buy good electronics…… many had over heating of their control boxes, ie 110 temp in the box but they all had internal heat sinks so they had to add fans…. I’m hoping to avoid that, my box is bigger than most and I’m planning on 24” of element lead wire ouside the box to keep that heat external as well…. Thanks again for your help…. I’m looking forward to building the chamber next.
 
  • Like
Reactions: tallbm
Edit. I see the heat sync is bolted to the SSR in the second picture... Did you use dielectric grease between the two ?... The box is sideways and wasn't seeing it on the top like you mentioned ...
 
...
The control box layout plan is to have a main illuminated power switch (15A fuse), with a 2A fuse for the PID power and then have an illuminated switch for the power to the element as well as a limit switch with an indicator light for the element to indicate a "hot" element. Sticking a piece of steel in the oven with a "live" element is...... well not a good idea.
...
Why not a switch on the door that interrupts power to element?
That is used on convection heat treat ovens so you don't inhale super heated air when adding or removing items
 
Why not a switch on the door that interrupts power to element?
That is used on convection heat treat ovens so you don't inhale super heated air when adding or removing items

It’s a bit subtle but the limit switch is for the open door. It interrupts the negative DC line from the PID into the SSR turning it “off” when the door is open. This could be on the power side but then all the amps would be going through it outside the control box. The SSR could fail closed but that’s what the element live light is for.
 
Last edited:
Edit. I see the heat sync is bolted to the SSR in the second picture... Did you use dielectric grease between the two ?... The box is sideways and wasn't seeing it on the top like you mentioned ...

I opted for the upgraded gasket Aubers makes for the SSRs vs the grease.
 
Just wanted to share a “finished” pic and it shows why you should have a wiring diagram sitting next to you when doing these type of things……I hooked it up to another heater and everything seems to be function as designed. All smiles here! This saved me about 300 bills from the plug and play control box. Once the oven is complete it will have saved me about 1600 bills.
28EF17F2-6B64-42B2-88F2-6D6607CCD3D3.jpeg

From the outside it will came out clean…..just need to add my heat shrink on the element wires, was just waiting to make sure they are long enough to reach the element.
AE1CFE88-8478-4F31-8E9D-074ED5431FC7.jpeg
 
Last edited:
Just wanted to share a “finished” pic and it shows why you should have a wiring diagram sitting next to you when doing these type of things……I hooked it up to another heater and everything seems to be function as designed. All smiles here! This saved me about 300 bills from the plug and play control box. Once the oven is complete it will have saved me about 1600 bills.
View attachment 656561
From the outside it will came out clean…..just need to add my heat shrink on the element wires, was just waiting to make sure they we’re long enough to reach the element.
View attachment 656562
Nice work and great savings man! :D
 
Excellent job right there... Very clean...

I used receptacles (electric and thermocouple) on the back side of my box... Two heat elements plug into it... And then the thermocouple has it's own kind of receptacle... This makes for easy storage and travel (portable) ...

Yes... much cheaper to build yourself ...

Wait'n to see the front...

edit; Oooops... I see it now...
 
Last edited:
Nice work and great savings man! :D
Thanks! I had a choice to get a press or a heat treat oven last year be fire prices went crazy and I got the coal iron press cause I could build the heat treat oven……
Excellent job right there... Very clean...

I used receptacles (electric and thermocouple) on the back side of my box... Two heat elements plug into it... And then the thermocouple has it's own kind of receptacle... This makes for easy storage and travel (portable) ...

Yes... much cheaper to build yourself ...

Wait'n to see the front...

edit; Oooops... I see it now...
Thanks JD 07! I looked at receptacles but wanted minimize connection points and this control box will be fixed to the oven…… but I can see now that I could have made it portable and used it for two different sized ovens….. I am planning on building another control box for my toaster oven for tempering….it fluctuates about 20-30 degrees and I want to it tighten that up…..

But I’m going to upgrade my quench tank first…..ie jacket it to have an anti-freeze tank with a block heater to pre heat my oil to the perfect quench temp…..
 
  • Like
Reactions: tallbm
Been enjoying some time away from work and have been working on my PID control box for my heat-treating oven. I found very good use for the new mini mill and milled the metal control box openings...... WOW where has this tool been all my life!

The control box layout plan is to have a main illuminated power switch (15A fuse), with a 2A fuse for the PID power and then have an illuminated switch for the power to the element as well as a limit switch with an indicator light for the element to indicate a "hot" element. Sticking a piece of steel in the oven with a "live" element is...... well not a good idea. Here is the control box face.
View attachment 652901
Inside the control box....
View attachment 652902

Here is my planned wiring diagram.....
View attachment 652900
Note I am an engineer but not a EE or electrician by any means, so I thought I would have a little "internet qc" by those that have built PID smoking units to verify I don't have any diagram flaws. Note I did add a dashed N line as an alternate path to avoid doubling up on the terminal block screw. I am also running the LED L lead through the terminal block to avoid an inline splice.

Any input from the more experienced would be appreciated.......

Very nice work. Your wiring diagram looks solid. I am working on an AC/DC controller now and have been bedeviled by issues.

JC :emoji_cat:
 
Very nice work. Your wiring diagram looks solid. I am working on an AC/DC controller now and have been bedeviled by issues.

JC :emoji_cat:
Thanks JC (and good luck, ie I do lots of time with the meter to make sure connections are good), I did lots of little electronics building way back, made my own circuit boards and such but that was a long time ago.... of those cool things were a metal detector and a TV signal jammer (this was great fun with siblings and neighbors....)
 
  • Like
Reactions: JC in GB
SmokingMeatForums.com is reader supported and as an Amazon Associate, we may earn commissions from qualifying purchases.

Hot Threads

Clicky