Schapansky on fri 16 oct 98
Dear Clayarters=3B
I'm at my wits end and hope that you all have some ideas on what I can =
do.
This is my problem: some time back I wrote to ask for help with my
kiln......it wasn't getting up to temperature no matter how long I fired. =
The
advice I received was that the elements might need replacing....as they can
slowly lose efficiency. I replaced the elements. My kiln still wouldn't =
shut
off. Witness cones indicated it wasn't even able to reach cone 5, much less=
6.
I talked to my local pottery supplier and though he said he wasn't very
famialiar with the duncan kiln=3B he felt it might be the top switch. (the
electrician who wired my kiln got a shock during the wiring.....he insisted =
he
didn't need to turn off the breakers........we thought maybe the high fire =
had
been fried).
I replaced the top switch.........no change. I decided to replace the =
bottom
switch as well......just to be sure I had covered all bases. IT STILL =
DOESN'T
WORK=21 And I have wholesale deadlines of Nov. 1. But isn't that always =
the
time things start to go wrong?
Now to give you all the particulars. My kiln is a second hand Duncan. =
Model
DX1029-2. 240 volts. 45 amps. Max. firing temp. cone 8. The infinite =
switches
I replaced were both inf 240 15 amp. The kiln is wired directly into the =
fuse
box. The box is upstairs by the back door and my kiln is in the basement. =
The
electrician used about 12 ft. of his cable from the box to a junction box in=
the
basement ceiling from here he used my heavy metal and rubber clad cable I =
bought
with the kiln (approx. 8 ft. of it).
Until I moved to Alberta from B.C. I had no problems reaching cone 6, with =
a
firing that started out on low over night, med. for 5 hrs. and 5 hrs on high
fire. I would then soak on high fire for half an hour. The glazes I used
turned out consistantly and beautifully. The kiln has a high and a high =
fire
setting. I still do not have any problems with the bisque firing to cone =
06.
Since getting it hooked up here=3B the firings slowly got longer and longer =
until
now .....as I said it won't shut off. Earlier problems of pinholing and =
a
slightly pebbly underfired look I can now also contribute to this problem =
and
not a water or glaze problem as I had feared.
Well, I guess thats about all I can think of, to tell you. Thanks in =
advance
for your help.
Sincerely
Elizabeth Schapansky
Clay Vision
Swan Hills, Alberta, Can.
Bruce Girrell on sat 17 oct 98
> The kiln is wired directly into the fuse box.
> The box is upstairs by the back door and my kiln is in the
> basement. The electrician used about 12 ft. of his cable
> from the box to a junction box in the basement ceiling
> from here he used my heavy metal and rubber clad cable
> I bought with the kiln (approx. 8 ft. of it).
You fail to mention a critical element here - the wire size.
A 45 amp circuit should have been installed using #6 AWG wire
(USA National Electrical Code - I would imagine Canada to be
very similar).
20 feet is a pretty long run, though. Even #6 wire at 0.41 ohms/1000 ft.
is going to cost you 16.6 volts at 45 amps (neglecting any contact
resistance), so your elements are being provided with, at best, around
223 out of your 240 volts, assuming that you actually have 240 volts
to start with. If, by chance, the kiln was installed with #8 wire, the
voltage drop across the wiring is about 26 volts.
Try these things:
1) Verify that the supply voltage at the service entrance is the full 240
volts.
2) Make sure that the electrician used the proper size of wiring.
3) Measure the voltage at the kiln running at full power (all switches on).
You don't have to wait for the kiln to heat up; just throww all switches
on and measure the voltage. Yes, I know the current draw will change as the
elements heat, but this should get us close enough.
If you have #6 wire, the voltage at the kiln should be about 220 volts.
4) Verify that all elements are operating. You can do this visually as the
kiln heats up or use a device called an amprobe (TM?) to measure the current
draw. With all switches on, you should be drawing the rated current.
5) You may have to go to heavier wire ($$$) or find a way to get your kiln
closer to the service entrance.
Once you have this information, your electrician should be able to recommend
some options to you, or you can come back here.
Bruce "stayed at a Holiday Inn Express last night[1][2]" Girrell
[1] from a commercial that airs in the US - Some person is in a situation
requiring technical expertise and offers very expert sounding advice. The
person receiving the advice acknowledges it and asks "Are you a
doctor/structural
engineer/etc?" The advice giver responds, "No, but I stayed at a Holiday Inn
Express last night." Then comes a voiceover "Holiday Inn Express - It just
makes
you feel smarter."
[2] Actually I _am_ an electrical engineer. Hope I didn't make any stupid
mistakes!
Amiram Khen on sat 17 oct 98
Hi Elizabeth
Your problem may be due to too thin and too long electric cables which cause a
voltage drop and prevent the kiln elements from developing full power. It is goo
practice to have the cables short and thick. Your electrician should be able to
advise on this.
Another possible cause is a malfunction of one of the relays in the control box
some other faulty connection. This can disconnect one of the elements, lowering
power input into the kiln.
A simple check is as follows:
Switch the kiln ON for about a minute, then switch OFF the kiln and disconnect t
kiln fron the mains. Use your finger to touch each element and feel if it bec
hot. If not - the element is disconnected somewhere. If you are not a trained
electrician I advise having one present.
I hope the above is useful,
Amiram
Schapansky wrote:
> ----------------------------Original message----------------------------
> Dear Clayarters;
> I'm at my wits end and hope that you all have some ideas on what I can do.
>
> This is my problem: some time back I wrote to ask for help with my
> kiln......it wasn't getting up to temperature no matter how long I fired. Th
> advice I received was that the elements might need replacing....as they can
> slowly lose efficiency. I replaced the elements. My kiln still wouldn't shu
> off. Witness cones indicated it wasn't even able to reach cone 5, much less 6
> I talked to my local pottery supplier and though he said he wasn't very
> famialiar with the duncan kiln; he felt it might be the top switch. (the
> electrician who wired my kiln got a shock during the wiring.....he insisted he
> didn't need to turn off the breakers........we thought maybe the high fire had
> been fried).
>
> I replaced the top switch.........no change. I decided to replace the bottom
> switch as well......just to be sure I had covered all bases. IT STILL DOESN'T
> WORK! And I have wholesale deadlines of Nov. 1. But isn't that always the
> time things start to go wrong?
>
> Now to give you all the particulars. My kiln is a second hand Duncan. Model
> DX1029-2. 240 volts. 45 amps. Max. firing temp. cone 8. The infinite switch
> I replaced were both inf 240 15 amp. The kiln is wired directly into the fuse
> box. The box is upstairs by the back door and my kiln is in the basement. Th
> electrician used about 12 ft. of his cable from the box to a junction box in t
> basement ceiling from here he used my heavy metal and rubber clad cable I boug
> with the kiln (approx. 8 ft. of it).
> Until I moved to Alberta from B.C. I had no problems reaching cone 6, with a
> firing that started out on low over night, med. for 5 hrs. and 5 hrs on high
> fire. I would then soak on high fire for half an hour. The glazes I used
> turned out consistantly and beautifully. The kiln has a high and a high fire
> setting. I still do not have any problems with the bisque firing to cone 06.
> Since getting it hooked up here; the firings slowly got longer and longer unti
> now .....as I said it won't shut off. Earlier problems of pinholing and a
> slightly pebbly underfired look I can now also contribute to this problem and
> not a water or glaze problem as I had feared.
>
> Well, I guess thats about all I can think of, to tell you. Thanks in advanc
> for your help.
>
> Sincerely
> Elizabeth Schapansky
> Clay Vision
> Swan Hills, Alberta, Can.
Dennis McAvoy on mon 19 oct 98
Elizabeth,
I feel the cause of your problem may be low voltage. When you bought the kiln
you specified 240 volt elements. In your previous location you probably had a
240 volt transformer supplying power to your studio? In the location you are
in now you probably have only 210 volts. This is also a function of the
transformer supplying power to your studio. 240 volt elements operating at 210
to 215 volts will take much longer to fire to the same temperature. To correct
this if it is the problem (you can measure the voltage yourself or call the
electric company and they can tell you) you will have to get 210 volt elements
to replace the 240 volt elements you now use.
Dennis
Smoky Mountain Pottery
Schapansky on mon 19 oct 98
Hi;
Thank you for your suggestions. I have had another electrician come in
and use his meters to measure voltage and amps. He felt that the cable
from the junction box to the fuse was capable of 50 amps. but I can't recall
what grade of cable it was. He did not read the volts at the kiln while on
high fire.
Since then I have had the power company out and they replaced the wiring
from the house to the transformer with a thicker one; and this is going to
give me about 4 extra volts into the house. From at total of 230 to 235; to
239/240.
I did do a visual on the elements.......turned both switches to high
fire and then watched them get red. Turns out that the bottom element has
an 18 inch. area at the back of the kiln that doesn't get red. So we
replaced that element with another new element last night (figuring that the
other one was faulty). Then we viewed it again. STILL DOESN'T GET RED IN
THAT SAME AREA!! I've talked to my duncan kiln rep. and another kiln repair
person in Calgary....they are mystified as to why this should be.
I'm a little leary of firing it again. I really think I must check with
the electrician again and maybe replace that cable from the junction box to
the fuse .
I am definitely learning a lot about my kiln though; I guess that can't
be a bad thing. Too bad it is happening when I don't have time to dawdle.
Thanks again.
Sincerely
Elizabeth Schapansky
Clay Vision
Swan Hills, AB
-----Original Message-----
From: Amiram Khen
To: CLAYART@LSV.UKY.EDU
Date: Saturday, October 17, 1998 8:30 AM
Subject: Re: desperate--11th hour kiln blues
>----------------------------Original message----------------------------
>Hi Elizabeth
>Your problem may be due to too thin and too long electric cables which
cause a
>voltage drop and prevent the kiln elements from developing full power. It
is goo
>practice to have the cables short and thick. Your electrician should be
able to
>advise on this.
>Another possible cause is a malfunction of one of the relays in the control
box
>some other faulty connection. This can disconnect one of the elements,
lowering
>power input into the kiln.
>A simple check is as follows:
>Switch the kiln ON for about a minute, then switch OFF the kiln and
disconnect t
>kiln fron the mains. Use your finger to touch each element and feel if
it bec
>hot. If not - the element is disconnected somewhere. If you are not a
trained
>electrician I advise having one present.
>
>I hope the above is useful,
>
>Amiram
>
>
>
>Schapansky wrote:
>
>> ----------------------------Original message----------------------------
>> Dear Clayarters;
>> I'm at my wits end and hope that you all have some ideas on what I
can do.
>>
>> This is my problem: some time back I wrote to ask for help with my
>> kiln......it wasn't getting up to temperature no matter how long I fired.
Th
>> advice I received was that the elements might need replacing....as they
can
>> slowly lose efficiency. I replaced the elements. My kiln still
wouldn't shu
>> off. Witness cones indicated it wasn't even able to reach cone 5, much
less 6
>> I talked to my local pottery supplier and though he said he wasn't very
>> famialiar with the duncan kiln; he felt it might be the top switch. (the
>> electrician who wired my kiln got a shock during the wiring.....he
insisted he
>> didn't need to turn off the breakers........we thought maybe the high
fire had
>> been fried).
>>
>> I replaced the top switch.........no change. I decided to replace the
bottom
>> switch as well......just to be sure I had covered all bases. IT STILL
DOESN'T
>> WORK! And I have wholesale deadlines of Nov. 1. But isn't that always
the
>> time things start to go wrong?
>>
>> Now to give you all the particulars. My kiln is a second hand Duncan.
Model
>> DX1029-2. 240 volts. 45 amps. Max. firing temp. cone 8. The infinite
switch
>> I replaced were both inf 240 15 amp. The kiln is wired directly into the
fuse
>> box. The box is upstairs by the back door and my kiln is in the
basement. Th
>> electrician used about 12 ft. of his cable from the box to a junction box
in t
>> basement ceiling from here he used my heavy metal and rubber clad cable I
boug
>> with the kiln (approx. 8 ft. of it).
>> Until I moved to Alberta from B.C. I had no problems reaching cone 6,
with a
>> firing that started out on low over night, med. for 5 hrs. and 5 hrs on
high
>> fire. I would then soak on high fire for half an hour. The glazes I
used
>> turned out consistantly and beautifully. The kiln has a high and a high
fire
>> setting. I still do not have any problems with the bisque firing to
cone 06.
>> Since getting it hooked up here; the firings slowly got longer and longer
unti
>> now .....as I said it won't shut off. Earlier problems of pinholing
and a
>> slightly pebbly underfired look I can now also contribute to this problem
and
>> not a water or glaze problem as I had feared.
>>
>> Well, I guess thats about all I can think of, to tell you. Thanks in
advanc
>> for your help.
>>
>> Sincerely
>> Elizabeth Schapansky
>> Clay Vision
>> Swan Hills, Alberta, Can.
>
Gavin Stairs on tue 20 oct 98
At 09:08 AM 19/10/98 EDT, you wrote:
....
> I did do a visual on the elements.......turned both switches to high
>fire and then watched them get red. Turns out that the bottom element has
>an 18 inch. area at the back of the kiln that doesn't get red. So we
>replaced that element with another new element last night (figuring that the
>other one was faulty). Then we viewed it again. STILL DOESN'T GET RED IN
>THAT SAME AREA!!...
Hi Elizabeth,
I think you've found the problem. That area that doesn't glow must be your
problem. There must be an open circuit (a break or a faulty joint) in the
element in that area.
If the area in question is one complete element, then look for a fault in
that circuit: check all the connections, redo them if necessary.
If the area is NOT a complete element, then it must have a short.
Normally, this would lead to overheating rather than underheating, but your
controller may be compensating for the fault by, in effect, turning
everything down.
Gavin
===============================================
Gavin Stairs
Stairs Small Systems (S3)
921 College Street, # 1-A
Toronto, Ontario, Canada M6H 1A1
(416)530-0419
Julie & Harold Deeley on tue 20 oct 98
Elizabeth,
I had the same problem a few months ago. Get your electrician or a
different electrician to check the voltage/amps actually being delivered on
the service to your kiln. The service we had installed was wired into a
faulty source and was not delivering the Voltage needed. We needed 220
volts and were actually only getting about190 which prevented the kiln from
reaching temperature. We had a different electrician fix the problem. A
second opinion might be worthwhile
Good luck!
>----------------------------Original message----------------------------
>Dear Clayarters;
> I'm at my wits end and hope that you all have some ideas on what I can do.
>
> This is my problem: some time back I wrote to ask for help with my
>kiln......it wasn't getting up to temperature no matter how long I fired.
>The
>advice I received was that the elements might need replacing....as they can
>slowly lose efficiency. I replaced the elements. My kiln still wouldn't
>shut
>setting. I still do not have any problems with the bisque firing to cone 06.
>Since getting it hooked up here; the firings slowly got longer and longer
>until
>now .....as I said it won't shut off. Earlier problems of pinholing and a
>slightly pebbly underfired look I can now also contribute to this problem and
>not a water or glaze problem as I had feared.
>
>Well, I guess thats about all I can think of, to tell you. Thanks in
>advance
>for your help.
>
>
>Sincerely
>Elizabeth Schapansky
>Clay Vision
>Swan Hills, Alberta, Can.
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