Fred G. Athearn on thu 22 aug 96
My wife Eleanora Eden asked me to comment on this because it
sounds like some of the things I have helped her with.
>>>>> "Jack" == jhcole@mgl.ca writes:
Jack> Synopsis: My controller (Orton Autofire) shut down the
Jack> kiln 3 times with error messages. In between it
Jack> reported unrealistic temperatures (see below) and
Jack> seemed to be out of control. I had no way to _take_
Jack> control; just had to sit and watch and hope. I am
Jack> considering a manual overide so that I never have to be
Jack> at its mercy again.
Jack> Does anyone else have manual overrides on their
Jack> controllers? What are they like? Where are they hooked
Jack> in?
The way the controller controls the kiln is by turning on and off
a 12 volt dc connection to the large relay that controls the
power to the kiln.
I have a replacement relay that runs on 110 volts and so I have
the fire control line from the controller wired to a small 12
volt relay that switches off and on 110 volts to the power relay.
To make a manual override I just have a switch that either sends
the 110 volts direct to the main relay in one position or routed
through the 12 volt relay controlled by the controller in the
other position.
But as I remember, the stock (smaller) power relay is switched
directly by the 12 volts dc from the controller. To make a
manual override with this setup you need to either get some very
big knife switch to switch the power either through or around
the power relay, or come up with an alternative source of 12
volts dc to switch onto the line to the relay in place of the
power from the controller. A car battery, battery charger, or
even a small 12 volt power supple from radio shack should do it.
You will not be able to get the 12 volts dc from the power supply
that comes with the controller because this supplies, I think, 32
volts ac. (Someplace, of course, the controller makes some 12
volt dc from this, but I don't know how to tap into it.)
Jack> First, I received an ERR1 message a few minutes after
Jack> starting. ERR1 means that the temperature was not
Jack> rising at the programmed rate; the kiln was shut
Jack> down.
This is a feature to keep the kiln from overheating if, for
example, the thermocouple has come out and is not heating up with
the kiln. It is not just a question of not heating at the
programmed rate but of the controller trying to increase the
temp. and getting little or no response for a period of time.
Of course if the kiln really is not heating you will also get
this error.
Jack> I threw the breakers and tried again- kiln
Jack> stillwouldn't start to heat.
There could be some sort of problem with your power source or
with the power relay.
Jack> Then I switched to the preprogrammed glazed program and
Jack> it kicked in.
Strange.
Jack> It was up to 229 degrees F. so I reprogrammed the first
Jack> step of my user program to 360 degrees per hour up to
Jack> 420 degrees, and tried it again. It started ok, but 20
Jack> miAnutes later there was another ERR1. Started it
Jack> AGAIN, and it behaved until just past 2030 degrees....
Jack> 10 minutes later the controller read 2154 degrees, and
Jack> proceeded to jump and read erratically every few
Jack> seconds. Over the next 15 minutes it made its way down
Jack> to 2065, then jumped again to 2100. 1 minute later it
Jack> had dropped all the way to 1948, and then it finally
Jack> started to read somewhat normally. It finally made it
Jack> to 2210 degrees and the hold started. Ten minutes later
Jack> I had an ERR2 shutdown ("Temperature more than 50
Jack> degrees away from set point") and a temperature of 2342
Jack> degrees.
One explanation could be a lose connection in the wiring for the
thermocouple. This would mean that the kiln really had started to
heat at the start but the controller had not seen this and
shutdown. Then somehow the connection started working off and on.
Another explanation could be a lose connection in the power
wiring. A lose connection could cause you not to start to
heating and then to work OK and then later to start to spark and
put noise on the line that would mess up the controller's reading
of the thermocouple.
One other thing that it could be is that there is a lot of noise
and/or voltage fluctuations on your house current because of
other users. The kiln may be on the same transformer as a lot of
other things and when motors turn on an off noise and voltage fluctuations
cause the temp readings to fluctuate, but this would not
explain the start-up problem.
The other explanation is that the controller is bad.
I would check all the power connections and the connections of
the thermocouple both at the thermo couple and the controller.
Then I would do a test firing (empty)
It would help to have a meter to be able to check if power was
coming out of the power relay and if the computer was sending
its 12 volt signal. I have a clamp-on amp type which makes it
easy to check that all the elements are working.
You might also check various parts of the wiring for heating and
sparks, including your fuse box.
Jack> Has anyone had a similar experience or have an idea
Jack> what might have caused these problems?
I once got some fluctuating temp reading because of line noise
caused by using four continuous controls at the same time as the
controller. Putting a spike suppressor (Varistor) across the
power supply to the controller, and routing the power to the
controller from a different circuit seemed to help.
--
Fred G. Athearn fga@sover.net http://www.sover.net/~fga
Rockingham, VT, USA finger for pgp key (802) 869-2003
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