Hot plate help, please?

[georgerkahn]

I was casting yesterday afternoon, and my hot plate -- at maximum -- would not get hotter than 211* F, as measured by the PID's thermocouple.

It is: GE SINGLE BURNER ELECTRIC HOT PLATE MODEL # 169163 1000 W

And, it used to get/keep my moulds up to 350*-375* with no problem. My question is two-fold (before I risk (again) embarrassing my self): Could I take it apart and short/by-pass the entire control part -- "rheostat" -- to simply have the heating coil switched by the PID? Or, assuming someone else on this forum has used this hot plate -- advise a repair? Neither a schematic not parts list has been found on Internet.

THANKS MUCH!
geo

[bedbugbilly]

George - probably someone on here will know. But if yo don't have any luck with advice - is there an appliance repair shop of any kind near you? I know in this "throw away" world, they are getting fewer and fewer but if there is, you might stop in and maybe someone could answer your question?

[jcren]

Mine is not a ge,but I use a cheap hot plate that sometimes won't heat up or will take too long between heat cycles. I tore it appart one day and found that the burner was only connected with spade connectors and they were slightly corroded and loose. Scraping and pinching with pliers gets it back to normal. I keep meaning to set-skrew them, but never think of it until the lead is melting!

[bangerjim]

There is no rheostat in there. It is generally a simple bi-metal strip thermostat that clicks on and off just like a lead pot. Accurate as the side of a barn.

You got some burning or corrosion going on. Take it apart and clean the contacts and check all the crimp connections.

You could use a controller to run it but that is really over-kill!

You cannot get much simpler than a hotplate circuit! There will be no circuit for it. It's just a simple loop of 120 hot in....thru the t-stat......thru the element.......and back to 120 return.

And are you using it on a circuit that will handle 1KW? Extension cord? 14ga circuit wiring?

Lots of things could cause your problems.

bangerjim

[JonB_in_Glencoe]

I'd take it apart and clean the connections, as advised by others.

If I were to never use the "built in" controller (T-stat), I'd remove it from the circuit. I'd test it outside, so as to not burn down the house, in case the mods weren't a correct thing to do.

I mention all the things I'd do. I can't speak for your "fix-it" abilities. If you aren't comfortable ripping it apart and/or mod'ing it, then I'd just find another one. I bought mine at a thrift store for $1, it was an older style with open coil heater element.

[wv109323]

I did essentially the same thing with my melting pot.(Lyman 20 lb.) I ripped the cord connection terminals and the thermostat out and ran wiring from the heating element to the SSR that is controlled by the PID. The spade terminals,thermostat , and the cord connection prongs were constantly overheating and burning themselves apart.
The type of PID you have may not support running your melting pot and the hot plate at the same time.

[bangerjim]

I did essentially the same thing with my melting pot.(Lyman 20 lb.) I ripped the cord connection terminals and the thermostat out and ran wiring from the heating element to the SSR that is controlled by the PID. The spade terminals,thermostat , and the cord connection prongs were constantly overheating and burning themselves apart.
The type of PID you have may not support running your melting pot and the hot plate at the same time.

You would need a dual channel controller to do both at the same time. Those little cheapo units everybody on here buys are only single channel. It is NOT the current draw you are worried about. It is the t/c input.....each are totally separate and the set points would also be different.

Dual channel controllers I sell are over a thousand dollars.

banger

[georgerkahn]

THANK YOU!!!! to ALL! I took it apart -- 1st thing I learned was I only needed to remove two little screws and one large nut on bottom -- but, the other five I removed went back in ok. Bangerjim hit the nail on the head, and I elected to bypass t-stat. I whupped out my Ungar soldering iron, a couple of inches of 12-ga copper wire, and soldered it right across the t-stat. I had been running it through a PID I had bought from Anton on this site anyway -- but plugged it in directly, first, to make sure no circuit breakers would trip. Nada! I'm lucky? I then put hotplate back under my 8" aluminum disk with the thermocouple in it; plugged it into the PID; and voila: It went up to 385* where I had it set, and maintained that temperature +/- about five degrees for my entire four hours of casting!!! My inverted steel bucket with square hole for mould heating kept it nice and toasty, too -- another great suggestion I gleaned from a forum post.
Again, thanks to all -- basically a simple fix to provide a unit now working better than when new to me (I bought it ?-hand at a thrift shop).
BEST!
geo