Sentry 3.0 SFTY setting

[davelea]

I have a used Paragon TNF273 with a Sentry 3.0 controller. The electrical panel on the kiln, and the instruction book, state the max temp for the kiln is 1288C, but when I look at the settings the SFTY (max temp the kiln is allowed to go to), is set at 1127C. 

I'd at least like to be able to get to Cone 6, what's going on? The manual says the SFTY can only be changed at the factory, so how is it so low?

[neilestrick]

Perhaps it was from a different kiln that was meant for glass work. You never know what people did before you got it. I would contact Paragon and see if it's possible for them to walk you through resetting it. Chances are there's just a code to access that portion of the programming. In the Bartlett controllers the access code to the Hidden menu is 443.

[davelea]

I've had an initial response back from Paragon saying that it could be the watts had to change for my area/electrical supply. I'm in the UK and the kiln is 11000 Watts 230 Volts, but it says on the same label the max temp is 1288.

[PeterH]

After a career in software engineering, is there any chance that it's "finger trouble"? We are all vulnerable, so double-checking can be worthwhile.

For example.

1) Carefully/blindly follow the instructions to display SFTY (maximum temperature) step by step.

2) Look to see what LIM (set maximum temperature) is set to, and then see how high you can set it.
- using the same name for two different things tends to lead to confusion (apparently factory setting and user setting).

From a quick glance at
https://www.manualslib.com/manual/1614345/Paragon-Sentry-3-0.html?page=25#manual

Edited September 5 by PeterH

[davelea]

I've had a look and the LIM is set to 1127, same as the SFTY setting. When I try to adjust it upwards it can't be increased past that. It's upper limit is set by the SFTY setting.

[PeterH]

On 9/5/2024 at 9:46 AM, davelea said:

I've had an initial response back from Paragon saying that it could be the watts had to change for my area/electrical supply. I'm in the UK and the kiln is 11000 Watts 230 Volts, but it says on the same label the max temp is 1288.

Well it was probably worth a try. To state the obvious, talk to Paragon again and emphasize the figures on the kiln plate.

Could you post all the figures on the kiln plate please, and do you have any idea of the resistance of your elements?

>  I'm in the UK and the kiln is 11000 Watts 230 Volts,

Do you have a special power supply, or are you just running it on the house mains?

PS For the experts.

I have reservations about the use of European  “harmonised voltage limits” when applied to heating equipment.
https://leadsdirect.co.uk/knowledge-base/what-is-the-difference-between-uk-voltage-and-european-voltage/

Surely the kilns elements should be designed for the "nominal voltage" in the country it is used in (i.e. 240V in this case). I would expect the kiln plate to reflect this stating the nominal voltage and the current at that voltage for the fitted elements.

Running the same elements at nominal voltages of 220V & 240V  will generate about  91% and 109% of the power generated at 230V. The differences from 100% being about the same as the point where you consider replacing the elements. (Not to mention the different house-wiring & breaker requirements.)

For the record https://shop.clay-planet.com/paragon-tnf-27-3.aspx   and choosing 240V single-phase gives
240V, 48A, 11500W, max 1287C    (checking V*A = 240*48 = 11520W)

Edited September 6 by PeterH

[davelea]

I had the kiln serviced and the elements were checked as ok. I don't remember the exact resistance. 

It's got a dedicated power supply from the fuse box.

Edited September 6 by davelea

[Bill Kielb]

1 hour ago, PeterH said:

Surely the kilns elements should be designed for the "nominal voltage" in the country it is used in (i.e. 240V in this case). I would expect the kiln plate to reflect this stating the nominal voltage and the current at that voltage for the fitted elements.

Agreed and the label needs to reflect the nominal voltage and amperage at same. To get to cone, The total wattage required to offset the thermal load and shell  losses meaning internal volume for speed and interior surface area for conduction or shell losses. Kilns with higher KW per interior unit area can tolerate more than a 10% reduction in KW so their design in effect is greater than 110% new. So I agree, this should be designed using the nominal 230v and wattage at that voltage to get to rated cone. The standard is a bit penal as you said but I suspect where possible the voltage is kept higher just for the sake of the grid.

It really looks like he has a sentry controller programmed for a lowfire kiln IMO, however it got there. I suggest asking paragon how can the safety be raised to that stamped on the kiln.

Interesting L&L thermal analysis for various kilns here. https://hotkilns.com/hk-pdfs/%3Asites%3Adefault%3Afiles%3Apdf%3ABTUS-Easy-Fire. Hopefully when all is said and done he ends up with prox 3.5 watts per interior surface per sq inch or if less more insulation in the shell.

This is my primary complaint about 110% design. The counter argument is we want it to naturally cool in a reasonable time.

Edited September 6 by Bill Kielb

[PeterH]

1 hour ago, PeterH said:

Do you have a special power supply, or are you just running it on the house mains?

Looking like it's a genuine 230V kiln  and I assume your house wiring is the UK nominal 240v supply?

PS

Kiln plate shows 230V 48A 11000W, while the 240V model is 240V 48A 11500W

So they have probably multiplied the element resistance by (230/240) to maintaining the current, which would reduce the wattage to ~11000W.

I cannot see how this would affect the max safe temperature when run at 230V. 

On a 240v supply the current would presumably rise from 48A to about (240/230)²*48A = 52A, which must reduce element life and change the wiring and breaker requirements.

Have to agree with Bill. It really looks like he has a sentry controller programmed for a lowfire kiln, however it got there. I suggest asking paragon how can the safety be raised to that stamped on the kiln.

But you probably have 230V elements, which isn't good if you are running it off a 240V supply.

Edited September 6 by PeterH

[davelea]

23 minutes ago, Bill Kielb said:

It really looks like he has a sentry controller programmed for a lowfire kiln IMO, however it got there. I suggest asking paragon how can the safety be raised to that stamped on the kiln.

I've asked Paragon this, waiting for a response now. I'm hoping I don't need to replace the controller...

[neilestrick]

What is your actual voltage?

[davelea]

11 minutes ago, neilestrick said:

What is your actual voltage?

230V, standard UK supply

[neilestrick]

2 hours ago, davelea said:

230V, standard UK supply

Then everything on the serial plate is correct, and the kiln should function perfectly fine once you get the controller peak temp sorted.

[PeterH]

1 hour ago, neilestrick said:

Then everything on the serial plate is correct, and the kiln should function perfectly fine once you get the controller peak temp sorted.

Well not quite -- as the UK supply is nominally 240V not 230V.

Since WW2 most of continental Europe has used a 220V supply, while the UK used 240V.

Come European “harmonised voltage limits” they showed "neither fear nor favour of the two sides" and defined things in terms of 230V.
https://leadsdirect.co.uk/knowledge-base/what-is-the-difference-between-uk-voltage-and-european-voltage/
So: 
- The UK's nominal 240V became the range 230V -6% +10% (i.e. 216.2 V – 253.0 V)
- Europe's nominal 220V became the range 230V -10% +6% (i.e. 207.0 V-243.8 V)
- This effectively means there is no real change of supply voltage, only a change in the “label”, with no incentive for electricity supply companies to actually change the supply voltage.

So the UK supply voltage remains nominally 240V.
... and the same kiln draws about 4.3% more current and about 8.9% more power than it would from a nominally 230V supply.

PS
Equipment designed to operate correctly of a voltage range 230V +/- 10% can operate on either of there standards, and most goods on the market are moving towards this.

BUT this isn't possible for simple heating devices.
- Europeans don't want their fan heaters to run 9% cooler than UK ones!
- A 9% hotter incandescent bulb runs brighter, but has a significantly short lifespan. (I found out the hard way).
- Kilns!

Edited September 6 by PeterH

[neilestrick]

9 minutes ago, PeterH said:

Well not quite -- as the UK supply is nominally 240V not 230V.

I asked for actual voltage, which they said is 230V. I was assuming they measured it.

[Bill Kielb]

5 hours ago, PeterH said:

BUT this isn't possible for simple heating devices.
- Europeans don't want their fan heaters to run 9% cooler than UK ones!
- A 9% hotter incandescent bulb runs brighter, but has a significantly short lifespan. (I found out the hard way).
- Kilns!

@PeterHI feel your pain and here in the States national standards have tried to minimize the impact of system voltage. Grid managers here use voltage to manage summer peaks, etc…. An interesting read to show just how complicated this can get for suppliers, manufactures and end users. https://powerquality.blog/2021/01/15/voltage-tolerance-boundary/#:~:text=The only national standard for,Voltage Ratings (60 Hertz).  Very likely the EU and Uk standards have evolved similarly for a best compromise.

[PeterH]

I just used my very old analogue ammeter to read the mains voltage in my UK house. I got 245V +/- 5%.

My equally old digital meter (accuracy unknown) oscillated between readings of 239V & 240V.

@davelea As Neil said measure your voltage. If your house is really receiving 240ish volts then I think there may be valid concerns running a kiln with elements designed for a 230v supply.  But the experts are much better judges of that than I am. 

BTW if your supply is 240V changing the elements to ones designed for 240V looks like a complete fix. The question then is does this need to be ASAP, or can you just wait until the elements need changing? I'm leaving that to the experts. The fact that you will be running hotter once the controller lets you may be significant.

PS

8 hours ago, Bill Kielb said:

Very likely the EU and Uk standards have evolved similarly for a best compromise.

For the record I think that the "nominally 230v"  was a good idea technically. It  helped create a unified market for (most) electrical goods in Europe (not just mainland Europe). The downside was that it introduced a certain amount of bureaucratic double-speak, whose impact seems to have worsened over the years.

At the stroke of a pen the nominal 220v European supply became nominally 230v, and the UK nominally 240v supply became nominally 230v. While as intended  the actual voltages supplied didn't change at all. (Although there could have been longer term changes in these voltages as the electricity grids changed over time).

Looking at wiki https://en.wikipedia.org/wiki/Mains_electricity_by_country
France and Germany are listed at an unqualified 230V, although the legislation said 230V -10% +6% (i.e. 207.0 V-243.8 V). The UK is also listed as 230V, although a footnote leads to an article that states that the range is really 230V +10% - 6% (i.e. 216-253v or 234.5V +/- 18.5V). 

[Bill Kielb]

2 hours ago, PeterH said:

BTW if your supply is 240V changing the elements to ones designed for 240V looks like a complete fix. The question then is does this need to be ASAP, or can you just wait until the elements need changing? I'm leaving that to the experts. The fact that you will be running hotter once the controller lets you may be significant.

My feeling is no, not likely an issue even for longevity sake. Manufactures have to consider this and governance needs to provide real minimum and maximums to be designed around. So it is generally baked (fired?) into the design for kilns by way of element thickness or gauge for longevity. As you discovered measuring (accurately) a bit more difficult than most probably realize and meter accuracy (Analog or digital) can be a significant thing. For non linear loading a good electrician supported by an electrical engineer can be very helpful as loads become more sophisticated. (Kilns and solid state relays?) In general my preference would be higher voltage than minimums because kilns tend to be designed with a minimal amount of heating energy and often fail to heat by element degradation before the elements burn open. Additionally some capacity can also be reduced in splicing, wire run length, gauge, relay contacts and now drop across SSR’s.

As far as running hotter, it ought to affect the speed but this minor increase should be covered by the PID action to regulate on time and desired rate to meet the traveling setpoint. Undersized element gauge or less element length (element loading) is generally not a thing for most kilns IMO.

Edited September 7 by Bill Kielb

[davelea]

RESOLVED! Paragon sent me the OEM config instructions which allowed me to reset the setting to it's default and now the SFTY is set to 1316C/2400F. Cone 6 awaits!

[Hulk]

Cool!

Can you post the OEM config instructions? ...others may find helpful, in future.

[neilestrick]

Running 230 volt elements on 240 volt service is not going to affect the firings in any way. The controller will cycle the elements as needed to maintain the proper rate of climb. The lifespan of the elements should not be affected enough to matter.

I've worked on a number of old kilns that only have one type of element available. The serial plates say 220 or 230, and the manufacturers say they'll work fine on any voltage. Basically, they run a little slow on 208 volts and a little fast on 240 volts.