Chapter 9 – Maintenance
Page 9-4 TestEquity 1007C Temperature Chamber
How to verify the chamber performance.
These tests verify the performance of the heating, refrigeration, electrical controls, temperature
controller, and air circulation systems. The chamber should meet all published performance
specifications if all of these tests are successfully passed.
These tests assume that the Temperature Controller’s setup and tuning values have not been
changed from the values as shipped from TestEquity. Also, the Limit Controller high limit must
be set to over +85°C (+88°C would be fine), and the low limit set to –75°C.
If the chamber fails any of these tests, it should be removed from service to prevent further
damage until the cause of the problem is determined and resolved.
1. The chamber interior should be empty and at ambient temperature, approximately +23°C.
2. Set the Temperature Controller Set Point to +85°C and turn the Master Switch ON.
3. The Heat Light should be ON continuously and the Cool Light should be OFF.
4. The chamber should heat up to about +80°C and begin controlling (Heat Light cycles
ON/OFF) within 7 minutes.
5. The chamber temperature should slowly increase and stabilize to +85°C. It should NOT
overshoot beyond +85°C by more than a few tenths of a degree, and the compressors should
NOT need to turn ON in order to maintain +85°C.
6. After stabilization, the chamber temperature should vary no more than ±0.5°C, or a total of
1°C.
7. Let the chamber stay at +85°C for two hours.
8. After two hours at +85°C, set the Temperature Controller Set Point to +93°C, or at least 5°C
above the setting of the Limit Controller. The chamber temperature will continue to increase.
The limit controller should trip at its high limit set point and the audible alarm should sound.
The chamber fan should stop and the temperature should stop increasing. Turning off the
MASTER switch on the chamber front panel lets you temporarily turn off the Audible
Alarm, even though the High Limit condition may still exist.
9. The Limit Controller will flash [Li;h1] (high limit) in the upper display and [Attn] in the
lower display, alternating with the actual chamber temperature in the upper display and
[FAiL] in the lower display.
10. The Limit Controller cannot be reset until the temperature is 2 degrees lower than its high
temperature set point. Then, you can press the RESET or EZ Key to resume normal
operation.
11. Set the Temperature Controller Set Point to –65°C. Turn the MASTER Switch back on if you
turned it off in step 8.
12. The high-stage compressor should turn ON within a few seconds. Then, the low-stage
compressor should turn ON within approximately 30 seconds, and the Cool Light should be
ON continuously and the Heat Light should be OFF.
13. The chamber should cool down to about –60°C and begin controlling (Cool Light cycles
ON/OFF) within 55 minutes.
14. The chamber temperature should slowly decrease and stabilize to –65°C. It should NOT
undershoot beyond –65°C by more than a few tenths of a degree, and the compressors should
NOT need to turn OFF in order to maintain –65°C.
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