Help Needed with KH Huppert 236DL 240V furnace

[TechyMechy]

I bought a really cute little KH Huppert 236DL 240V furnace. It was given to the owner and I couldn't test it for the owner really didn't know what the furnace was and he had no way to plug it in at his house. I gave it a 50/50 chance that it would work but the price was right... I got the furnace home and changed the plug so it fit my 240 outlets and the darn thing seems to work!

I have done some packed carburization surface hardening in my shop. I have another small furnace that can fit the sealed box for packed carburization and I am going to use this little furnace for hardening/quenching and annealing. I have a number of punches and dies to make and I'm hoping that this will help speed up my process (the carburization takes about 1 day to heat up and cool off - I can do both processes in parallel now).

I think I'd like to change the furnace over to a digital controlled furnace.

1. Does someone have a recommendation for a programmable soak/ramp PID controller for this furnace
2. Does someone have the actual manual/wiring diagram for this furnace?
3. I need a little kiln plate - does anyone know where to get this?

I am thinking of using multiple SSR's so that this is safe. I want to run this overnight and have it shut itself off in an alarm condition

Please help me find an inexpensive, but capable programmable soak/ramp PID controller for this furnace.

 

[extropic]

Linked is a 7 year old thread about a complete oven build, including controls schematic (reply #40) and programing info (reply #62).

Heat Treat Furnace Build

Thanks @Linghunt Electromagnetics was my most difficult class. PID looks interesting. I wish I knew more control systems theory. -brino EM classes were interesting and tied so many of the other classes together for me. The picture I selected was a typical boundary value problem. No only does...

www.hobby-machinist.com

 

[markba633csi]

Aliexpress and Ebay have packages you can buy that come with everything you need

 

[woodchucker]

You can always view Stan's videos on the hotshot ovens.
And I know that he recently stated that the new ones are using a new pid, more advanced.
HotShot ovens were sold to American Rotary.
But here's a start.

Shadon HKW

The life of a millwright, lower than a tool and die maker, lower than a machinist, above a contractor, wheres a body to fit in? I choose to spend my spare time in the shop repairing and restoring vintage machinery, I work as a systems installer, I install for HAAS, AFC systems, GFS and ITW...

www.youtube.com

edit: https://www.americanrotary.com/what...n-our-novus-controller-vs-tap-pro-controller/

 

[TechyMechy]

Thanks for the replies.

The Hot Shot ovens look nice, but I have a nice start and I want to update the controller. I ran the oven today and all of the elements work - which is just great. I'm positive that the gage is off but I could compare it to my Fluke probe (which I know is pretty darn close).

I like the look of this controller alot:

Wi-Fi 1/16 DIN PID Temperature Controller with Ramp/Soak [AW-SYL-23X2P] - $129.99 : Auber Instruments, Inc., Temperature control solutions for home and industry

wifi wi-fi wireless PID temperature temp controller module 1/16 DIN 48*48

www.auberins.com

But I don't know who else makes a programmable slope, dwell controller that can be programmed (and possibly has a phone app).

The 7 year old post is helpful, but I am hoping to get a suggestion on the more recent devices.

I think I'll use 2 SSR's (one for each circuit on my oven) so if a SSR fails closed, I can control with the second one.

Here's a link on the Knife Dog's forum for the oven I have. I have the 240V oven:

Converting 1962 Huppert's Delux Furnace Model 236dl 240v, 7.5a

Hi everyone. I recently bought at auction a 1962 heat treat oven (wasn't cheap). Paid $500 for it. It's really heavy and looks very well built. The temp display stopped working and wasn't reliable even while it worked. I'm wondering if I should just replace the thermo couple with a type S or K...

knifedogs.com

The Infitrol is an interesting controller with a bimetallic strip and a built in heater. I'm not too sure how the Hart switch works. It almost seems like a potentiometer but has three outlets (two hot and one ground?). I'm not sure if it is a tapped potentiometer or if it is stacked pot with one return. I'll have to try to figure this out.

I'll probably be into this for a couple of hundred dollars before I'm done, but it will be a nice little oven. I have another, larger, dental burn out oven that I use for my packed carburization and it can have multiple ramp soak times per program. I really like that oven. I think that using one for carburization and one for the heat treatment and annealing would be the ticket.

Does anyone have a suggestion of where to get kiln shelves for this besides Amazon?

Thanks again for your input.

 

[Larry$]

Checkout Automation Direct. They also are helpful about answering questions.

 

[woodchucker]

The Hot Shot ovens look nice, but I have a nice start and I want to update the controller. I ran the oven today and all of the elements work - which is just great. I'm positive that the gage is off but I could compare it to my Fluke probe (which I know is pretty darn close).

the hot shot ovens were only pointed at for the pid and scr.. not to replace your oven.

 

[TechyMechy]

Thanks,

I looked at Automation Direct web site but couldn't find any programmable soak/ramp PID controllers and SSR's. But, then I searched on Google for temperature controllers on Automation Direct and I found the items. I'll look them over.

Understand now about why you pointed me to the Hot Shot ovens.

I'll keep looking...

Thanks for your responses.

 

[TechyMechy]

I read the 7 page thread from 2018 - very helpful!! I really like the idea of using a switch and a contactor for isolating the heating elements. I'm thinking of adding a door switch so if I open the door, the elements will power off.

Does anyone know what type of high temperature wire one should use to run from his control box to the kiln? THHN max service temperature is 194F.

I like the wireless capability of the Aubrey controller but I really appreciate the links to the HotShot equipment too. Stan does really, really nice work. The wireless, programmable capability of the TAP controller is impressive, but the price is just prohibitive. I only paid $35 for my oven and won't be using it all of the time. I'd like to keep my total cost under $300 for this unit. If I could have bought a new furnace for his initial prices (less than $700), I would have just bit the bullet and bought one of his units. He really is a craftsman.

My slightly larger dental burn out oven (6" cube inside) cost me $80 and it has the programmable digital controller but it doesn't have the wifi capability. I am going to use this one as my packed carburizing furnace and the Huppert as the hardening/annealing furnace.

 

[extropic]

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Also search for "high-temperature cable" for multi-conductor.