Super System T4413 User Manual

CARBON SENSOR TROUBLESHOOTING

Technical Data

There are several key components in all atmosphere control systems. When a difficulty
arises, it is important to identify the cause with minimum effort and expended time. The
procedure that follows is designed to aid in that process.

INTRODUCTION

The starting point for any troubleshooting procedure is to properly identify the symptom
that necessitates it. The cause of the symptom can often be elicited by answering some
preliminary questions.

Is this a startup problem, or has the system been operating under control? If this is a
startup problem, it is necessary to establish that all system components have been
properly connected and configured for the application.

If the system has been operating properly and there has been either a gradual or sudden
change in the control performance, it may conceivably be a problem with the probe. In order
to establish the correct performance of the carbon sensor, resist the temptation to remove
the sensor from the furnace. All of the tests outlined here must be done while the sensor is
located in the furnace, at temperature, and exposed to a reducing atmosphere. This
procedure can be performed on the SSi Gold Probe and on most other manufacturer’s
sensors. We strongly recommend that you call us at 800-666-4330 before you remove the
probe.

NOTE: IF YOU HAVE ALREADY REPLACED THE PROBE AND THE PROBLEM

PERSISTS..…THE PROBE MAY NOT BE THE PROBLEM!

SUPER SYSTEMS INC – TECHNICAL DATA SHEET

7205 EDINGTON DRIVE, CINCINNATI OH 45249

Phone: [phone] Fax: [phone]

www.supersystems.com

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CARBON SENSOR TROUBLESHOOTING

Technical Data

PROCEDURE

Does a shim stock analysis, a 3-gas analysis (SSi PGA3000) or a dew point analysis (SSi
DP2000) verify the indicated value from the probe? If the values are close to the same, the
problem is not likely the Gold Probe. If the values are not similar, continue with the
following steps:

1 Verify that both mV and t/c cables between the sensor and the controller are clean and

connected firmly to the Gold Probe and controller terminals. Verify polarity.

2 Verify that the reference air supply is connected to the reference air fitting. This will be

the fitting closest to you when you face the probe. It has been found that on occasion the
reference air has been connected in error to the burn off fitting, causing low readings.

3 Check that the reference air is flowing. Disconnect the air supply at the probe and

submerge it in a cup of water. Bubbles verify the flow.

4 Verify that no air is flowing into the burn off fitting by submerging the burn off tubing in

a cup of water. (Flow can occur if the burn off air pump is subject to external vibration.)

5 Leak test

Verify that reference air is flowing at 0.5 to 2.0 scfh. Turn off the reference air for one minute
and read the Gold Probe output millivolts. Turn the reference air back on and note the change
in mV. It should not display more than a 5 mV increase.

6 Is the controller COF set to the proper value? This factor is referred to by other

descriptions such as Process Factor, Furnace Factor, CO Factor, Circulation Factor,
Calibration Factor, etc. The factor may require adjustment to eliminate any offset or
discrepancy between the indicated carbon potential and the actual achieved result in the
work pieces or shim stock.

- this test can detect a cracked or broken substrate in your Gold Probe.

SUPER SYSTEMS INC – TECHNICAL DATA SHEET

7205 EDINGTON DRIVE, CINCINNATI OH 45249

Phone: [phone] Fax: [phone]

www.supersystems.com

T4413 Page 2 of 4

CARBON SENSOR TROUBLESHOOTING

Technical Data

1 Do the sensor temperature and MV output as measured by an independent digital

calibrator agree with the indicated values on the controller with one sensor and one t/c lead
disconnected? If not, there is most likely a controller calibration problem or a cable problem.

2 Does the Gold Probe mV signal return to within 1mV of it's original value in 1 minute

as measured by a digital VOM after it has been shorted for 5 seconds? If it does not, go to step

10.

3 Probe impedance (resistance) test-

determine the electrical integrity and reliability of the Gold Probe. Some contemporary
controllers can perform it. If yours does not, conduct this simple test: at process
temperature, disconnect the controller cable at the Gold Probe mV output and measure the
mV value with a VOM. Then shunt the signal with a 100 kilo ohms resistor. After 10 seconds,
read the new mV value, divide the original value by the new value, subtract 1 from the result
and multiply by the value of the shunt resistor (=100). The calculated value is the sensor
resistance in kilo ohms, which should be less than 25 kilo ohms.

4 If the problem is not corrected by probe and/or furnace burnout as described in the

Gold Probe Manual and your system manual, and the problem is a faulty probe, contact SSi at
[phone] and describe your problem to our technician. You may then request a Returned
Material Authorization for repair or replacement of your Gold Probe.

5 WARNING - even though you suspect a faulty sensor, DO NOT

from a hot furnace at a rate faster than 2 inches per minute. Cool the sensor on an insulating
medium to avoid thermal shock. This will prevent damage that is expensive to repair.

Our technical support staff is available Monday – Friday, 7:00 a.m.to 6:00 p.m. EST to assist
you and answer your atmosphere control problems.

this is one of several electrical tests that

remove your Gold Probe

SUPER SYSTEMS INC – TECHNICAL DATA SHEET

7205 EDINGTON DRIVE, CINCINNATI OH 45249

Phone: [phone] Fax: [phone]

www.supersystems.com

T4413 Page 3 of 4

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Notes:

CARBON SENSOR TROUBLESHOOTING

Technical Data

Written by Stephen Thompson

SUPER SYSTEMS INC – TECHNICAL DATA SHEET

7205 EDINGTON DRIVE, CINCINNATI OH 45249

Phone: [phone] Fax: [phone]

www.supersystems.com

T4413 Page 4 of 4