Cress Kiln Model FX-23B - Testing it?

[Babs]

Yeh get the temp/hr increase needed for a bisque firing and glaze firing for your pots.

Then I guess you experiment or get help from a potter with your first firings. Keep notes if what you're doing and adjust the settings accordingly.

Have you fired any kiln?

Does your kiln have a thermocouple and pyrometer?

[Dan18z]

I have a Cress FXT23P In fair shape. It's been sitting around for 10 years, between the last owner and  my purchase of it for $250. I have a 240v 40amp  single phase (4 wire) supply from the breaker box to a 4 lead wall plug, but the kiln calls for 208V at 34amps. Amps are not a consideration since  the wall circuit is able to supply the 34amps draw through the 40amp wire and hardware. 
FX23FFTX23F-208-VAC.pdf
The question is  how can i supply the 3 lead pigtail from the kiln with 208V's. 208v appears to be available on a three phase circuit or a step down transformer (have not been able to find a 240 to 208v step down that doesn't drop the supply amps below 34.

The Cress technician suggests replacing the coils to accept the 240v supply i have, but that doesnt address ground and common.  Also the wiring diagram says the coils have the same spec 

FX23F-FTX23-220.pdf

[Dan18z]

I have determined that 208 require a 3 phase feed. That makes it a requirement to replace the existing 208v/8ohm heating elements with 240v/10ohm capacity. Hardware  (4 coils) will be $300 with 2.5hrs of estimated labor.

Does that seem like an appropriate amount of time to replace and pin the coils?

Thanks for any feedback.

 

[neilestrick]

@Dan18z  208 volt does not necessarily mean 3 phase. Both 240V and 208V can exist as single phase or 3 phase. Typically 208V is delivered as 3 phase, but you can hook up a single phase circuit with that. And sometimes 240V is delivered in 3 phase.

But yes, typically you need different elements for each voltage, as the element resistance determines how many amps the kiln draws, which in turn determines how many watts. Watts are the important number for heating the kiln. Some of these old kilns are listed as 220V, and they run fine on either 208V or 240V. Others have specific elements for each voltage. If Cress said you need to change them to run correctly on your 240 V service, then you'll need to change them. For 4 elements it should only take about an hour for a kiln tech to do the work if that's all that's being done. Is the $300 just for the elements?

[Dan18z]

. Thanks for getting back to me. The 240v coils x4 are $75 from cress. I only have single phase run to my house and no way to wire it to 208. Changing coils is the solution per Cress Tech. I’m takIng it into Freeform in National City CA on Monday he quoted two hrs at$75hr. Does all that sound reasonable?

[neilestrick]

13 hours ago, Dan18z said:

. Thanks for getting back to me. The 240v coils x4 are $75 from cress. I only have single phase run to my house and no way to wire it to 208. Changing coils is the solution per Cress Tech. I’m takIng it into Freeform in National City CA on Monday he quoted two hrs at$75hr. Does all that sound reasonable?

$75/hr is reasonable, but it should only take an hour to do 4 elements at most.