MAINTENANCE WITH Q & A
81
QUESTIONS & ANSWERS
The input voltage label says 230 VAC (or 208 VAC). I thought I had 220 VAC. Is that OK?
208V and 230V are NOT the same. 220V is a misnomer in the United States—there is no such standard
as nominal 220V in the United States though 220V does exist in Europe. You must verify the exact type
of electrical service you have. If there is any doubt, you must consult with a qualified electrician who is
familiar with industrial plant wiring. In addition, the input line voltage should be measured while the
chamber is operating in the COOL mode to ensure that the expected nominal voltage of either 208V
±5% or 230V ±5% is present.
Why doesn’t the chamber come with a power cord and plug?
Most local and national electrical codes require permanent wiring for this type of equipment. If used
as a portable device, a flexible wire with a plug may be acceptable, but local and national codes may
limit the length to 6 feet. Cincinnati Sub-Zero recommends that the appropriate method for your
installation be determined by a qualified electrician who is familiar with industrial plant wiring.
Why does my chamber heat or cool slower than the published specifications?
Performance is significantly affected by the characteristics of your test sample. Factors include size,
weight, material, shape, and power dissipation if energized. The test sample should be placed in the
chamber in a manner that allows for air circulation. You should not place the test sample directly on
the chamber floor. It should be placed on the shelf. Multiple test samples should be distributed
throughout the chamber to ensure even airflow and minimize temperature gradients. If necessary,
additional shelves should be used to evenly distribute the load.
How can I modify the chamber to cool faster?
Unfortunately, there is little you can do to improve upon the designed-in performance. Cincinnati Sub-
Zero does offer an LN2 boost package that can be installed in the field to increase cooling
performance.
Why is there water/ice/snow in the chamber?
Any time the ambient air is subjected to temperatures below the dewpoint, moisture will condense
out of the air. The effect is ice or frost during low temperature operation. When the chamber is
heated above 0°C, the ice or frost will turn into water. To avoid moisture condensation, make sure the
port plugs are inserted at all times. Also, avoid opening the chamber door while the chamber is
operating at temperatures below room ambient. When a low temperature test is completed, warm
the chamber to at least room ambient before opening the chamber door and before removing your
test sample.
How accurate is the chamber?
That’s a loaded question! There is no “chamber accuracy” specification as such. The answer requires
an understanding of several performance parameters.
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