Low Oven Temperature; High Oven Temperature; Programmed Oven Temperature Not Cooling Or Slow To Cool - ABB PGC2000 Operation And Service Manual

Low Oven Temperature

It is the customer's responsibility to ensure that the area is safe and and hazard-
free, and will remain so the entire time the analyzer is open. This responsibility
includes ensuring adequate ventilation in analyzer shelter and obtaining proper
work permits, etc.
See "AIR PURGING" in Section 4 for the override function. Do not perform
override until you have read Section 4 completely and you understand and can
perform the procedure requirements.
Symptom: Oven temperature is below the specified set point value.
Cause: Low oven temperature can be caused by the following:
1. Low air pressure to analyzer ovens. Perform Test Procedure 1 (Carrier, Makeup, and Utility Gas
Supplies) and make necessary adjustment at analyzer air regulator(s).
2. Loss of air pressure switch; wiring or connection is defective. Perform Test Procedure 23 (Loss
of Oven Air).
3. Defective temperature probe. Perform Test Procedure 21 (Open Temperature Sensor), Test
Procedure 22 (Shorted Temperature Sensor), Test Procedure 24 (Isothermal Oven Overtemp
Sensor Open), Test Procedure 25 (Zone Input Sensor Open), Test Procedure 26 (Open or
Shorted Heater), and Test Procedure 27 (Open Fuse to AC Conditioning Board), as applicable.
4. Heater orifice restricted by foreign matter. Check the heater orifice to ensure it is not restricted or
plugged.

High Oven Temperature

Symptom: Oven temperature is above the specified set point value.
Cause: High oven temperature can be caused by a runaway heater or defective temperature probe.
Perform Test Procedure 22 (Shorted Temperature Sensor), Test Procedure 24 (Isothermal Oven
Overtemp Sensor Open), Test Procedure 25 (Zone Input Sensor Open), Test Procedure 26 (Open
or Shorted Heater), and Test Procedure 27 (Open Fuse to AC Conditioning Board), as applicable.

Programmed Oven Temperature Not Cooling or Slow to Cool

Symptom: Programmed temperature oven ramps to final set point, but will not cool to initial set point
or is slow to cool to initial set point.
Cause: Cool down is initiated by the selection of temperature control table entry #2 in the method
tables. If this instruction is missing or incorrect values are placed in the temperature parameters, cool
down will be effected and may not occur. Cool down causes a cool down solenoid to increase the
cool air flow from the vortex cooler into the programmed temperature oven. If the cool down solenoid
or vortex cooler fails, cool down will not perform as expected. If the air flow to the vortex cooler is
inadequate, cool down will also be affected. A rate of 0.1 is needed to activate the cool down
solenoid in the temperature control table entry #2.
The following can cause problems with programmed temperature oven cool down.
1. An error has been made in programming the method table. Perform Test Procedure 30
(Checking Temperature Table Values) to verify all control parameters.
2000-OSM, F1
CAUTION
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