Paragon kiln element

NickWheeler

NickWheeler

Joined
Dec 3, 1999
Messages
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So I got my Paragon KM24-D kiln back from the service shop in Portland and they replaced a relay and the door kill switch.

It's running real nicely, but takes forever to heat up. It's averaging 55 minutes to get to 1450 from room temp (~55F). It took a couple minutes shy of 2-1/2 hours to get to 2000F (just to check).

Bill Burke has been nice enough to email me back and forth trying to come up with a solution.

I realized the element in mine is not the one that they USED to put in the 24" kiln. A technician told me they discontinued using a 16 ohm element as the controller couldn't keep up with it and temp control was not good.

I see Evenheat uses something like a 16 ohm element as their 22.5" kiln is running 15 amps and 3600 WATTS with 240 volt input.

So do any of you guys running 3600 WATTS have temp control issues?

I don't want to screw up temp control, but an hour to get to a temperature that most folks can achieve in 15-30 minutes seems ridiculous.

Thanks! :)
 
Last edited:
Nick
My evenheat is 3600 watts and it will hold 1950 deg within 2-3 degress for a 40 min soak with no problem.Heck I can run my whole H/T cycle with 1 hour of total soak time in 1hr35Min.
Stan
 
Nick, it takes me 30-45 to reach 1500 from a cold room temp (around 40F). I have the Evenheat 22.5", and I have no control issues. It bounces up and down a few degrees above and below target for a minute or two, and then it evens out nicely.

--nathan
 
Not quite answering the questions you asked... since my Sugar Creek (according to their webpage) is a 2530W unit (at 230V)... which calcs to about 20-ohms. I'm guess-timating that my kiln takes about 35-40 minutes to reach 1500F, and with the digital controller, it holds temp well (varying between + or - 10F from the set point).

Erin
(Counting his Jeffersons)
 
Well.... the nerd in me punched numbers just in case anyone is wondering or wants to tell me I figured this wrong.

My kiln says right on the side of it that draws 8 amps and makes 1800 WATTS... which doesn't quite compute. I come up with 1920 WATTS.

WATTAGE = Voltage X Amperage
240 Volts X 8 amps = 1920 WATTS

The technician claims my oven has a 22 ohm element and draws 11 amps. That would be nice, because
240 Volts X 11 amps = 2640 WATTS

To check the amp figure she gave me... Amps = Voltage/Ohms
240 Volts / 22 ohms = 10.9 Amps

I told her my element was 30 ohms and she told me I was wrong. BUT! If you do the math on the numbers right on the side of my kiln (plus I checked it with a zero'd out multimeter!)

Ohms = Voltage/Amps
240 Volts/8amps = 30 ohms

So I DO have a 30 ohm element. I think this is too wimpy. A 22 ohm element would be nice as it would heat up faster and still be easily controlled by the controller. A 16 ohm element would definitely get hot fast, but I'm concerned about it being too much for the controller.

So what would you do if you were in my shoes?
 
I've actually been considering one of the Sugar Creek kilns. I have an Canadian copy of a 16" paragon. When I got it used, I replaced the element right off the bat (sent all the specs to Paragon, and got the element from them), now the darn thing takes approx 3 hours to reach 1950F! Prior to replacing the element it took about 2 1/2 hours, and when I spoke with folks at Paragon, their first suggestion was to replace the element. Sorry I'm not being helpful with your question Nick, but I feel your pain on the heat up time! I hate the fact that if I want to heat treat something that requires higher temps, I have to turn the oven on as soon as I open the shop at 6:30am...and then hope that I can put the blade(s) in there by 9 or 10am! It's frustrating.
 
The question is not if it will be too much for the controller but too much for the relay. The controller just supplies a low voltage the ssr which turns on and off the high amps. The relays have a wide amperage rating, if yours in too small they are not that expensive to replace.

I would check the circuit and see what ssr you have and what the cost to replace would be if needed.
 
I agree. I wouldn't be worried about the controller. Most have fuzzy logic to be able to "learn" whatever the conditions are in your oven and adjust to maximize the performance/accuracy.

Heck, even if it did create some wider swings, if it only takes 20-30 minutes to get to temperature, you can easily let it sit for another 20-30 to heat soak and the temp swings will even out. But I think the controller will be able to compensate. With my home built, I had some pretty big overshoots, so I always set the target temp to 50 below what I wanted, and once it reached that temp, I just crept the temp up until I reached my desired temp, and that took care of the overshoots.

--nathan
 
Well Paragon just stepped up in a BIG way. I'm glad too, because I paid the extra money for Paragon as it's supposed to be the best and I was really starting to question that.

Don't feel the need to read all this if you don't want, but I'm just gonna copy/paste so the whole thing is laid out. (I'm a big, goofy, open book like that).

I emailed Bob (Paragon's director of engineering) for help.

Good on you Bob and Paragon!!! :thumbup: :cool:


email right out of my account:



Nick,

This furnace has users with very different demands.

1. Those who need to get to terminal temerature as quickly as possible but stability at temperature is not an issue. 16 Ohm element

2. Time to reach temperature is not important but stability is. 30 Ohm element

3. Compromise between 1 and 2. 22 Ohm element.

I will have Laura send you a 22 Ohm element.

Bob
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On Mon, Mar 22, 2010 at 3:41 PM, Nick Wheeler <merckman99@yahoo.com> wrote:
Hello Bob-


I hope this finds you well.

I have a KM24-D that I purchased quite awhile back (s/n 370660) that, unfortunately, I have not been able to use until just recently. It has sat inside my shop with VERY LITTLE use.

When I finally got to use it recently, it wasn't getting past 1100F and would just start cooling off randomly.

I took it to Mitch McDougal at Roses Glassworks in Portland, OR (a Paragon service shop). Mitch replaced a relay and adjusted the kill switch on the door. It works fairly well now, except it takes a really long time to heat up.

My kiln only has a 30 ohm element. I talked with a technician on the phone (Laura) that disagreed with this, but if I use the numbers right on the side of the kiln I come up with 30 ohms. It also registers 30 ohms on my multimeter. (240 volts / 8 Amps = 30 ohms)

The replacement element on the website is listed as a 16 ohm element. This would draw 15 amps and make 3600 WATTS. Laura told me that Paragon quit using that element due to control issues.

The catch to all this, is that Laura told me my kiln is supposed to have a 22 ohm element. That would draw 11 amps and make 2640 WATTS.... which would be better (I think) but does NOT match the numbers on the side of my kiln.

I really am not happy with the fact it takes almost 2.5 hours for my kiln to reach 1900F.

However, I don't want to sacrifice temp control if the controller really cannot handle a 16 ohm element. It seems like a 22 ohm element would be a good compromise.... heating faster but still controllable, but I can't find anything listing a 22 ohm element for my kiln. My only knowledge of it is Laura saying that's what the schematic showed for my kiln.

Can you give me your thoughts on this please?

I know a $1500 kiln is not a big deal considering how many kilns you guys make/sell a year, but it was a big purchase for me, and I REALLY WANT it to work as well as possible.

Thank you for your time, it IS appreciated.


-Nick Wheeler-​
 
Nick, I sent you an email but basically what I found out is that the "new" sentry II controller that Paragon is now using has over run problems with the 16 ohm element. But if you set the controller to ramp at the same temp that you want to reach the over run is negligible. Ie ramp 1550, temp 1550 hold xxx

OOPS sorry came back to this and didn't reload the page before posting.
 
I'm glad this all got figured out, Nick. Please let us know how long it takes once you get the 22 amp element, I'm curious what to expect once I get one.

Is there any place in that controller where you can set the ramp rate? I suppose if there was, this would have been brought up a long time ago. The larger ovens that we use at work have this as a menu item.

Anyhow, good to hear that Paragon came through.
 
Yea Troy, it's one of the command prompts when you're setting the controller. Full firing rate is set as 9999

I may order a 16 ohm element along with the 22 they send me just to keep one as a back up (I wish they were easy to swap out). Well, I don't think changing them out is hard, it's just the fact that the element gets brittle after being fired a lot (at least the ones they showed me at the glass shop were anyway).

Thanks for posting guys! :)
 
Hey Nick...

Just a comment on your calculation question.

NickWheeler said:
Well.... the nerd in me punched numbers just in case anyone is wondering or wants to tell me I figured this wrong.

My kiln says right on the side of it that draws 8 amps and makes 1800 WATTS... which doesn't quite compute. I come up with 1920 WATTS.

WATTAGE = Voltage X Amperage
240 Volts X 8 amps = 1920 WATTS
Click to expand...

You probably already know all this but...

Wattage does, in fact, equal volts times amps... but the issue may be that Paragon did not use 240v as the voltage for calculating the 1800 watts.

I work for the power company up here in Everett. When we talk about single-phase residential secondary voltages we frequently say 120/240V, because these are the voltages we commonly see on the secondary side of our tranformers. However, residential electricians and equipment manufacturers will often use 110/220v or even 230v in calulations because there is a certain amount of voltage drop between our transformers and the equipment that is plugged into your receptacles. So your kiln may say 8amps on the sided... but if Paragon tested the power consumption on a circuit with input voltage of 225v, they could easily come up with 1800W.

Actual wattage calcs are kind of fuzzy since it all depends on your input voltage... and where it falls in the range of 220-240V (some equipment can even operate at 208V for those facilities where 120/208V three phase is present and two legs of the "Y" are tapped for single-phase 208V).

Isn't electricity fun.

BTW... I think you'll be happy with the 22-ohm element.

Oh... and this is only a theory, but I think one way of minimizing the temperature swings that can accompany a lower-resistance (ie 16-ohm) element is the use of a thermal mass block inside the kiln. Maybe try placing a big chunk of steel plate in your kiln to help smooth out the thermal bumps. :D

Erin
 
Ditto what Nick said about the folks at Paragon....I picked up a used Paragon kiln with no specs or manual at a yard sale and the people at Paragon were EXTREMELY helpful via email and phone to help me understand it and get it operational.....great service BEFORE they even sold me anything !! Now that is a company worth doing business with.
 
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