OPERATION

With the system wired as illustrated in Fig. 1, and the power switch off, close the burnoff airflow valve.   Set the upper (burnoff) time (T1) to about 5 minutes, and the lower  (cycle) time (T2) to 12 hours. Set the delay timer (TR106) to 5 minutes. Record the initial probe millivolts, then close the power switch (SW-1) to start a cycle.  Set the reference air flow to full scale, or slightly higher. Observe the probe temperature and O2 millivolt reading, then increase the burnoff airflow until the millivolt reading is less than 200 millivolts, preferably close to zero.  The temperature should be less than 50oF higher than it was initially. When the burnoff is complete, observe the probe millivolts and note the time to recover to within 2 millivolts of the initial reading. Set the delay timer, TR106, to this value. Repeat the burnoff by turning the power off, then on. Observe the performance and adjust flows and times to values that cause the probe millivolts to drop close to zero (or at least below 200mV) when the burnoff period is complete. The ultimate goal is to provide the shortest practical burnoff time so the process is not out of control for an appreciable period.  If trim gas or air are added by motorized valves, and they are not spring return types, the control interrupt terminals (Fig.1) can be used to interrupt power to the motors so that control is maintained during burnoff. For time proportioning control with solenoid valves simply supply the power to the valves through the control interrupt terminals 1051 and 1053. When all flow and time parameters have been set observe the operation for a day or two to make sure all is correct. Refer to your GOLD PROBE^TM instruction manual for a complete description of the probe conditioning operation.