Electric Kiln Firing for 48+ hours on high still not reaching temp

[Dolly606]

I'm using a 1227 skutt 1980 kiln with sitter..its always been quite slow to fire. But, this is a first.. it have been on high for 48 hours and still not reached temperature. First- is that safe for it to be on for so long? Second it is hitting cone 5 but not cone 6. Its very close. My cone is starting to bend but its just not there. -also all elements, relays, and wiring are 100%.

Is it ok to keep letting it run and hope it hits cone 6 in the next few hours or should i shut the kiln off since its been cone 5 for over 24 hours...? 

[neilestrick]

Shut it off! Anything longer than a couple of hours more than normal is a waste of electricity, and probably just cost you $50 or more. There's clearly a problem with the kiln, and your glazes most likely will not be the same as in a normal firing.

[Dick White]

As Neil recommends, shut it off, it's not going anywhere new tonight. Also reconsider your notion that everything is 100%. If I were going to place a bet on one single item, I would bet that your elements are long overdue for replacement. That they have electrical continuity does not mean they are producing the designed amount of heat. Get a multimeter if you don't already have one and measure the resistance of each section at each switch setting, and compare to the specifications in the Skutt document at

https://skutt.com/pdf/service_manual/11-5_ks_resistance.pdf

As noted in the technical reference, if your measured resistance is more than 1.5 ohms over the spec, that will explain why the kiln never got to temperature.

[Denice]

I have the same kiln and replace the elements when I get into the 10 to 12 hour zone.   I hand build so I fire slower than most people who throw.   Denice