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Thermo runaway

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#46974

Thermo runaway | 24 January, 2007

Hello,

My first time post up here. I have a problem with thermo runaway on upper zone #5 on the Omni 10 Electrovert. We changed the thermocouple #5 but the problem came back up. We swapped Sensoray board 8 and 9, swapped board #3 (T/C interface board), and changed board #1. The error still comes up once a while. The last thing we did was changed another thermocouple and the thermocouple wire that ran all the way back to the thermocouple interface board. The problem is intermitten. The machine can run fine for 3 months without a problem or the problem came up twice in one day. Thanks for any advice.

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SWAG

#46981

Thermo runaway | 25 January, 2007

You might consider installing a noise kit as it sounds like you've tried almost everything else. Electrical interference on these machines causes erratic problems, especially as they get older. I would call Speedline tech. and see if they think the noise kit has any bearing on this symptom. Something you could do for no $ is check all the electrical grounds you can find on the chassis near the transformers and also make sure your stacks are electrically isolated close to the machine. These two things might help reduce noise problems.

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#46993

Thermo runaway | 25 January, 2007

What about the relay that controls the heater? I've seen that problem on conceptronics ovens. The relay would latch on and never turn off.

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#46998

Thermo runaway | 25 January, 2007

We swapped the solid state relay for zone 5 bottom to zone 5 top but the problem came up once a while. As for noise protection, there are jumpers at E1 to E8 and E9 to E16. They are hardware filters and prevent noise spikes from affecting thermocouple readings.

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#47000

Thermo runaway | 25 January, 2007

Does the t/c read the actual skyrocketing temperature (you could confirm with a profiler if you wanted to leave it running while it's setting itself on fire) or something much lower than reality, driving the heaters harder?

I would probably start swapping t/c inputs at the controller and see if I could force a different zone display out of whack. Just don't forget where they were when you started.

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#47001

Thermo runaway | 25 January, 2007

stupid back button

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SWAG

#47009

Thermo runaway | 25 January, 2007

The noise kit I'm referring to involves the installation of a new interface card in your PC, a new sensoray interface card in the card cage (brd 7), soldering/bridging of two DC COM points and new DB cables.

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#47017

Thermo runaway | 26 January, 2007

Had the same thing happen here. If the thermocouple line shorts out the temperature appears to go runaway (999F or whatever the max of your software is). Ours was a short out in a socket where the thermo plugged in to pass through the frame.

Regards

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