Duncan EA 1020 Not reaching Temp

[Kerry S]

Hi,

I have owned a second hand Duncan EA 1020 studio plus kiln for around 12 years and have mostly been firing at the lower temps from cones 020 to 04. Cone 04 usually took around 6 hours. This kiln is an Automatic/Manual kin.  30amp. The Kiln is rated to fire to cone 8.  It has a 20 hour timer.   Element ohms have been tested and are slightly better than required

Recently I wished to fire to cone 6. This has become a sticking point.

 I did a firing mid last year for cone 6, set the timer for 15 hours. The Kiln reached cone 4 almost 5.

The next cone 6 firing was 20hours and the sitter shut it off.  Witness Cones 4 and 5 were fully bent cone 6 was not quite there. Due to the time taken none of  my glaze finishes were right and I ended up with a lot of browns  which wasn't expected.  I thought this was a bit long but I'm not sure with this kiln.

If it takes 20hrs to reach cone 5/6 It is never going to reach cone 8. The kiln slows right down on ramp after 900degrees celcius. I think it is relying on soak times to get to the required cone.

I've emailed paragon several times about parts and advice, they seem to think 10 hours was reasonable for cone 6. But if cone 04 takes 6 hours then I'm not so sure.

I have replaced elements, relay switch, fixed Interval timer and about to replace the Repeat Cycle timer. 

As I'm running out of parts to replace and can't seem to find any information on how long this kiln would normally take to reach the temps I'm hoping someone here could answer this. 

Thanks for your time.

Regards Kerry

 

 

 

[neilestrick]

@Kerry S Even a cone 8 kiln should reach cone 6 in 12-15 hours. Since you've replaced just about everything else, have you checked that your power cord is in good condition, and it's not heating up during the firing? A 12+ year old power cord is pretty old. If it is getting hot, it could be the cause of the problem. Check the connections where the power cord connects inside the kiln and make sure there's no corrosion. Also check the plug and outlet and make sure they're not getting hot during firing. Check the condition of the wires that feed the outlet and see if they're corroded where they connect to the back of the outlet. Any one of those things could be affecting the power.

[Bill Kielb]

3 hours ago, Kerry S said:

Hi,

I have owned a second hand Duncan EA 1020 studio plus kiln for around 12 years and have mostly been firing at the lower temps from cones 020 to 04. Cone 04 usually took around 6 hours. This kiln is an Automatic/Manual kin.  30amp. The Kiln is rated to fire to cone 8.  It has a 20 hour timer.   Element ohms have been tested and are slightly better than required

Recently I wished to fire to cone 6. This has become a sticking point.

 I did a firing mid last year for cone 6, set the timer for 15 hours. The Kiln reached cone 4 almost 5.

The next cone 6 firing was 20hours and the sitter shut it off.  Witness Cones 4 and 5 were fully bent cone 6 was not quite there. Due to the time taken none of  my glaze finishes were right and I ended up with a lot of browns  which wasn't expected.  I thought this was a bit long but I'm not sure with this kiln.

If it takes 20hrs to reach cone 5/6 It is never going to reach cone 8. The kiln slows right down on ramp after 900degrees celcius. I think it is relying on soak times to get to the required cone.

I've emailed paragon several times about parts and advice, they seem to think 10 hours was reasonable for cone 6. But if cone 04 takes 6 hours then I'm not so sure.

I have replaced elements, relay switch, fixed Interval timer and about to replace the Repeat Cycle timer. 

As I'm running out of parts to replace and can't seem to find any information on how long this kiln would normally take to reach the temps I'm hoping someone here could answer this. 

Thanks for your time.

Regards Kerry

 

 

 

A 10 hour glaze firing is no problem. The critical part of the firing is about the last 250 degrees. If you can go approximately 108 degrees per hour for this segment your cone six cone will bend reasonably close to the temperature indicated by the center column on the Orton chart and you will have done the proper amount of heatwork for cone six glazes. The problem arises when kilns can’t reach their top temperature at a reasonable rate, things eventually overfire when they do or never make it and under fire. This is almost always a function of how much power a kiln has which is why it is often better to buy a cone ten rated kiln to get more cone 6 firings per element set replacement. Even on a cone ten kiln wear and tear of As little as 10% of the available power dooms them to element change in 100-150 firings.
 

Having said all that I think you can simply turn everything to manual and high power, let’s say midfire and see if it will make it to cone six quick enough to be a reasonable firing. If not, you do not have enough power and if everything else is functioning and you tried this on manual, your elements are most likely unable to provide the required power. The other thing to mention is if energy leaks out of the kiln anywhere, you simply do not have spare power to make it. So if your kiln is leaky, or your port plugs are out these things certainly do not help.

Most likely you do not have sufficient power to regularly fire to cone 6, but realistically it’s only a cone 8: kiln. Try full manual fire, full power after midfire.  if it makes it, ya got a way to do this for now.

[Kerry S]

14 hours ago, neilestrick said:

@Kerry S Even a cone 8 kiln should reach cone 6 in 12-15 hours. Since you've replaced just about everything else, have you checked that your power cord is in good condition, and it's not heating up during the firing? A 12+ year old power cord is pretty old. If it is getting hot, it could be the cause of the problem. Check the connections where the power cord connects inside the kiln and make sure there's no corrosion. Also check the plug and outlet and make sure they're not getting hot during firing. Check the condition of the wires that feed the outlet and see if they're corroded where they connect to the back of the outlet. Any one of those things could be affecting the power.

Thanks for the advice, I will be checking the power cord and all the other wiring next. 

The kiln is hard wired directly to the power board so no plugs to worry about.

We have earth leakage safety switch as well  so any electrical faults tend to trip the power.

My trouble really started when I replaced the elements the firings became longer instead of the other way around.

Then we found a burnt out part and it has been downhill since.

Yesterday I tried a manual firing and didn't make it past 1050 degrees celcius.

Any way will look at everything you've suggested wish me luck.

Thanks again.

Kerry

 

 

 

 

 

[Kerry S]

15 hours ago, Bill Kielb said:

A 10 hour glaze firing is no problem. The critical part of the firing is about the last 250 degrees. If you can go approximately 108 degrees per hour for this segment your cone six cone will bend reasonably close to the temperature indicated by the center column on the Orton chart and you will have done the proper amount of heatwork for cone six glazes. The problem arises when kilns can’t reach their top temperature at a reasonable rate, things eventually overfire when they do or never make it and under fire. This is almost always a function of how much power a kiln has which is why it is often better to buy a cone ten rated kiln to get more cone 6 firings per element set replacement. Even on a cone ten kiln wear and tear of As little as 10% of the available power dooms them to element change in 100-150 firings.
 

Having said all that I think you can simply turn everything to manual and high power, let’s say midfire and see if it will make it to cone six quick enough to be a reasonable firing. If not, you do not have enough power and if everything else is functioning and you tried this on manual, your elements are most likely unable to provide the required power. The other thing to mention is if energy leaks out of the kiln anywhere, you simply do not have spare power to make it. So if your kiln is leaky, or your port plugs are out these things certainly do not help.

Most likely you do not have sufficient power to regularly fire to cone 6, but realistically it’s only a cone 8: kiln. Try full manual fire, full power after midfire.  if it makes it, ya got a way to do this for now.

Hi Bill

Tried the full manual yesterday didn't make it past 1050 degrees celcius 21hours so there is definitely a power problem some ware. 

As I mentioned to Neil the main trouble started with replacing the elements. I could actually reach cone 6 with the old elements but it was taking a bit long.

After replacement the firings became slower, then we found a burnt out part and on it goes , hasn't been up to speed since.

I have one more part to replace then wiring . 

Thanks for the advice, hopefully we can track down the problem just process of elimination I guess.

Cheers

Kerry

 

 

[neilestrick]

3 minutes ago, Kerry S said:

Hi Bill

Tried the full manual yesterday didn't make it past 1050 degrees celcius 21hours so there is definitely a power problem some ware. 

As I mentioned to Neil the main trouble started with replacing the elements. I could actually reach cone 6 with the old elements but it was taking a bit long.

After replacement the firings became slower, then we found a burnt out part and on it goes , hasn't been up to speed since.

I have one more part to replace then wiring . 

Thanks for the advice, hopefully we can track down the problem just process of elimination I guess.

Cheers

Kerry

 

 

Get a multi-meter and verify that you have full power going through all the switches. Maybe you've got a dead leg somewhere. Also check that you wired up the elements properly. Is your Duncan a typical Duncan where you've got twice as many elements and each loops only once? It's easy to get the feeder wires messed up on those, lots of connections. When you turn it on high, do all the elements glow after a while?

[Kerry S]

On 6/18/2020 at 1:37 AM, neilestrick said:

Get a multi-meter and verify that you have full power going through all the switches. Maybe you've got a dead leg somewhere. Also check that you wired up the elements properly. Is your Duncan a typical Duncan where you've got twice as many elements and each loops only once? It's easy to get the feeder wires messed up on those, lots of connections. When you turn it on high, do all the elements glow after a while?

Hi Neil,

Yes I do have one of those kilns with 8 elements.

Did another firing yesterday on manual high setting after replacing the last part ,Infinite switch and capacitor. Have now replaced Relay switch, fixed Interval timer , Repeat Cycle timer and just for good measure  I  replaced the elements again after noticing the ohms were a little high on the new ones put in previously. All elements glow red. . Takes 6 to 7 hours to reach 1000 degrees Celcius. then it goes nowhere after that.

The Kiln ran for 20 hrs until the timer turned it off. I just peeked into the top peep hole cone 6 guide has just started to bend slightly. I have had 2 Electricians look over the kiln and both have said electrically all is good. There is enough power getting to kiln and they have no idea what is going on. 

I'm sure it's some simple oversite as I could get to cone 6 in around 15 hrs before it blew out to 20 hrs plus before replacing the elements.

I've run out of Ideas and parts.

If you think of anything at all let me know 

Thanks Kerry