Chapter 8 – Maintenance
Page 8-4
TestEquity 115A-EX 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. 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.
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 –74°C. The ambient
temperature
must
be approximately 23°C for the cool down times to be valid.
All temperature readings below are as indicated on the temperature controller.
1.
The chamber interior should be empty and at ambient temperature, approxi23°C.
2.
Turn ONLY the MASTER Switch ON. Set the Temperature Controller Set Point to
+85°C. Then, turn the TEMP Switch ON.
3.
The Heat Light should be ON continuously.
4.
The chamber should heat up to about +80°C and begin controlling (HEAT Light cycles
ON/OFF) within approximately 15 minutes.
5.
The chamber temperature should slowly increase and stabilize to +85°C. It should NOT
overshoot 85.5°C, and the compressors should NOT need to turn ON in order to
ma85°C.
6.
After stabilization, the chamber temperature should vary no more than ±0.2°C, or a total
of 0.4°C.
7.
Let the chamber remain at +85°C for 30 minutes.
8.
After 30 minutes at +85°C, set the Temperature Controller Set Point to –65°C.
9.
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 HEAT Light
should be OFF.
10.
The chamber should cool down to about –60°C and begin controlling (Cool Light cycles
ON/OFF) within 1 hour and 36 minutes (96 minutes).
11.
The chamber temperature should slowly decrease and stabilize to –65°C. It should NOT
undershoot beyond –65.5°C, and the compressors should NOT need to turn OFF in order
to maintain –65°C.
12.
After stabilization, the chamber temperature should vary no more than ±0.2°C, or a total
of 0.4°C.
13.
Set the Temperature Controller Set Point to +23°C. The chamber should begin to heat up.
The compressors should turn off within approximately 1 minute.
14.
This concludes the chamber performance verification tests.
15.
Let the chamber heat up to +23°C before turning the chamber OFF.
