Chapter 8 – Maintenance
Page 8-4
TestEquity 123C Temperature Chamber
How to Verify the Performance
These tests verify the performance of the heating, cascade refrigeration mode, 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 EZ-Zone 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, approxi23°C.
2.
Turn ONLY the Power Switch ON.
3.
Set the F4 Controller Set Point to +85°C. Then, turn the Conditioning Switch ON.
4.
The Heat Light should be ON continuously and the Cool light should be OFF.
5.
The chamber should heat up to about +80°C and begin controlling (HEAT Light cycles
ON/OFF) within approximately 12 minutes.
6.
The chamber temperature should slowly increase and stabilize to +85°C. It should NOT
overshoot 85°C by more than a few tenths of a degree, and the compressors should
NOT need to turn ON in order to ma85°C.
7.
After stabilization, the chamber temperature should vary no more than ±0.2°C, or a total of
0.4°C.
8.
Let the chamber stay at +85°C for two hours.
9.
After two hours at +85°C, set the Temperature Controller Set Point to –65°C.
10.
The high-stage compressor should turn ON within a few seconds. Then, the low-stage
compressor should turn ON within approximately 30 seconds, the Cool Light should be ON
continuously and the Heat Light should be OFF.
11.
The chamber should cool down to about –60°C and begin controlling (Cool Light cycles
ON/OFF) within 1 hour and 40 minutes (100 minutes).
12.
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.
13.
After stabilization, the chamber temperature should vary no more than ±0.5°C, or a total of
1°C.
14.
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.
15.
This concludes the chamber performance verification tests.
16.
Let the chamber heat up to +23°C before turning the Conditioning Switch OFF.
