Temperature controller for kiln

[JDB3]

Has been a while since I did any control work. Guy asked me about a "temperature controller" that he had bought for his used "kiln". The kiln came with a contactor type controller (wax would melt, and then would shut off power when temperature reached the temperature).
The new controller is all digital. Power supply is 240 volt. I instructed him to connect power (from line side of contactor) to terminals 1 & 2. Temperature controller (sensor) yellow wire to terminal 9 & red wire to terminal 10. Then, from terminal 13 & 14, go to coil of the contactor.
Does this sound right ? I am asking cause he had looked at other diagrams that (to me) do not apply!


Thanks,

 

[K8MHZ]

Has been a while since I did any control work. Guy asked me about a "temperature controller" that he had bought for his used "kiln". The kiln came with a contactor type controller (wax would melt, and then would shut off power when temperature reached the temperature).
The new controller is all digital. Power supply is 240 volt. I instructed him to connect power (from line side of contactor) to terminals 1 & 2. Temperature controller (sensor) yellow wire to terminal 9 & red wire to terminal 10. Then, from terminal 13 & 14, go to coil of the contactor.
Does this sound right ? I am asking cause he had looked at other diagrams that (to me) do not apply!
View attachment 14664View attachment 14665View attachment 14666

Thanks,

If the coil voltage on the contactor is also 240 volts, it looks like diagram 11 is what needs to be followed.

Are you sure the contactor has a 240 volt coil?

 

[JDB3]

If the coil voltage on the contactor is also 240 volts, it looks like diagram 11 is what needs to be followed.

Are you sure the contactor has a 240 volt coil?

The original wiring on the kiln has 2 hots & 1 grounding conductors. The green grounding conductor, is attached to the frame. Also the original control was feed (2 wires) from the line side of the contactor & then from the original controller (2 wires) to the load side of the contactor. So I am 99.99% sure it is all 240 volt.
Thanks for the reply.

 

[mpoulton]

Is there actually a contactor there already? The original electromechanical control you mentioned (usually called a "kiln sitter" after the first brand name) does not always contain a contactor. Some are strictly mechanical and directly actuate the switch contacts. Even if there is a contactor there, it would be a good idea to replace it with a new solid state relay instead. The digital controller will tend to cycle on and off much more often than the old kiln sitter, wearing out the contactor faster.

Does your customer know that this controller is not well suited to a ceramics kiln? It has no ability to set a ramp-and-soak profile, which is what ceramics need for a proper firing cycle. They must be warmed very slowly at first, then heated faster, raised to peak temperature, and held there for awhile. You can't just turn the kiln on full blast until it reaches a set temperature, which is what this controller will do. Digital kiln controllers are available and work very well (I have one from Orton) but they are not the same as these general-purpose industrial temperature controllers.

 

[K8MHZ]

Is there actually a contactor there already? The original electromechanical control you mentioned (usually called a "kiln sitter" after the first brand name) does not always contain a contactor. Some are strictly mechanical and directly actuate the switch contacts. Even if there is a contactor there, it would be a good idea to replace it with a new solid state relay instead. The digital controller will tend to cycle on and off much more often than the old kiln sitter, wearing out the contactor faster.

Does your customer know that this controller is not well suited to a ceramics kiln? It has no ability to set a ramp-and-soak profile, which is what ceramics need for a proper firing cycle. They must be warmed very slowly at first, then heated faster, raised to peak temperature, and held there for awhile. You can't just turn the kiln on full blast until it reaches a set temperature, which is what this controller will do. Digital kiln controllers are available and work very well (I have one from Orton) but they are not the same as these general-purpose industrial temperature controllers.

If the customer is using the kiln for ceramics, I agree with the above. Trying to replace a kiln-sitter with a PDI and a contactor may not produce the desired results for ceramics. Kiln sitters are still available, and so are the temp cones.

If the customer is using the kiln as, say, a heat treat furnace instead, then the PDI controller would be a better choice.

 

[JDB3]

I will get with him to ask these questions. Thanks again.

 

[JDB3]

Any other ideas on this, till I can get back with him?