awaiting word from arsenal....but
i took it apart and the air part blows fine the heating element won't heat....but if i short it out past the contact points and the one resistor looking thingy... the elements glow red.
i'm not much of an electrician so , in dummies speak, how do i fix this.
i'm just assuming here that once the elements come up to a certain heat range the points break and it cools to a lower temperature...then like a
P.I.D. they reconnect and the cycle begins again.
Well if the heater works and the blower works that kind of leaves it in the temp control components. I don't have one or a schematic to help anymore than that.
Not lots of data but it sounds like the thermostat is dead. A PID is more complex than a thermostat, same function, the PID just does it more precisely, that's not needed for case drying though :)
You asked FA about parts or repair costs, so that's a good step.
If they can't fix it or won't fix it then we should be able to figure out some workaround. I haven't taken mine apart, yet :)
Schematic is quite simple, ac power in goes to (hopefully) a fuse, maybe a thermal overrun safety device, them the fan is across live and neutral and the heater is across the fan, in series with the thermostat. Thermal overrun device is OK and fuse is OK, otherwise the fan wouldn't spin up, so it's just the thermostat, they should be able to sell one.
There is a known problem with the temperature controller. The controller goes to high temp and sticks there. Then the hi temp safety blows. A friend replaced the safety on mine and the first time I used it the new safety blew.
His next suggestion was to replace the temp controller with a fixed resistor. I haven't done that yet.
Thermostat replacement with a fixed resistor? That would tend to melt the area around said fixed resistor, plus you would have zero control of how hot your case dryer got, sounds like a recipe for annealing the bases of your cases, a bad thing, unless I am misunderstanding you here.
Thermostats measure temperature and switch the heater on / off but do not heat much at all, a good thing since most of it is inside the middle area of the "lid"...
If I was going to do a cheap workaround I'd use a power diode to run the heater at half power, BUT there would still be zero guarantee that the bases of your cases wouldn't be annealed so soft that you'd get a face full of chamber gasses...
And - since the fan IS running, we already KNOW that the thermal cutout isn't dead, as those always are wired in to kill everything, should they blow open to protect the cases from softening.
I believe you may be misunderstanding my suggestion. The thermostat has already failed and stuck on the highest temperature possible. That leads to the failure of the high temperature safety. The thermostat is a rheostat which is basically a variable resistor. If it is replaced by the correct fixed resistor you can keep the temperature down to an acceptable level.
If you disassemble the brass dryer, you will find that the thermal cutout does not cut off the current to the fan. There is a very good reason for this. You want the fan to keep running if the temperature is hot enough to blow the thermal cutout.
Then replace the thermal also. You should be able to find the numbers on the side and and order off the internet. If you leave a safety out of the loop, you are looking at a melt down.
Sorry, incorrect, PJEagle. A thermostat is a switch, controlled by a thermal detector of some kind (bimetallic switch, sometimes something exotic like a wax motor, something that moves in response to the temperature.)
Not a variable resistor, as that's wasteful.
https://en.wikipedia.org/wiki/Thermostat
The OP, mozeppa, said, "i took it apart and the air part blows fine the heating element won't heat....but if i short it out past the contact points and the one resistor looking thingy... the elements glow red." - So we maybe should ask mozeppa what the resistor looking thingie is, if it's the overtemp safety then it's one thing, if it's something else, another. A picture would help.
Overtemp safety devices are always marked with a temperature and current i.e. "I can carry up to 5 Amps and I self destruct at 200 degrees F" or whatever. They cost $1 or so if you get them off DigiKey or Mouser etc., plus shipping of course.
if you get tired of messing with it, I picked up 2 food dehydrators with working fans and thermostats at thrift stores within the last month- one was $8 and the other $15. I also see them all the time at yard sales.
Loren
My $5 solution from a yard sale. I have 3 dehydrators and 2 of them were given to me. I really missed the boat on wet tumbling. I should have done it 20 years ago.Quote:
Originally Posted by rockshooter
YMMV
https://live.staticflickr.com/65535/...c4b3b372_c.jpg
update!
Called Frankford Arsenal... man on the phone asked me to send him a pix of the dryer....i did... got a new on in the mail few days ago...way to go F. A.!
now if i could figger out how to fix the old one...i'd have two dryers!
Quote:
Originally Posted by fatnhappy
Best answers in the thread!Quote:
Originally Posted by rockshooter