MAINTENANCE WITH Q&A
Page 5-12
cost and can be installed in the • eld.
Dedicated 230V 50Hz models are available for MC(H)-3 units. Note that the cooling performance will be
slightly reduced at 50 Hz. Please call Cincinnati Sub-Zero for details on re-con• guring for 50 Hz. operation.
How often should I charge the refrigeration system?
This chamber uses a closed-loop refrigeration system. Just like your refrigerator at home, it does not need
periodic charging. If the charge is low, this means that there is a leak. Leaks should be repaired before
recharging.
What kind of Freon does the chamber use?
The word Freon® is a DuPont registered trade name for their CFC-based refrigerants and is incorrectly used
as a generic term for refrigerants. Cincinnati Sub-Zero chambers do not use CFC-based refrigerants. The
high-stage system uses R-404A, which is also known as DuPont Suva® HP62. The low-stage system uses
R-508B, which is also known as DuPont Suva® 95.
My static pressure is lower than the data plate speci! cation. Is this an indication of a
leak in my refrigeration system?
This does not always mean that there is a leak. Ozone friendly refrigerants use POE oil which has the ability
to absorb refrigerant to the point of actually causing a lower pressure reading. A decrease in the chambers
performance along with lower pressure readings is a possible indicator of a leak. (Please contact Cincinnati
Sub-Zero if this occurs).
What is the hissing and clicking sound when my unit is at or approaching set point?
This is normal. The sounds are caused by the solenoid valves alternating between cooling and bypass.
What is the average air " ow rating inside the chamber?
The average air fl ow is 60-80 feet per minute in an empty chamber. The airfl ow velocity over your test
specimen depends on several factors, including test specimen size, geometry location within the chamber.
Sometimes I see bubbles in the 404 sight glass. Does this mean my
chamber has a leak in it or is undercharged?
This does not necessarily mean that the unit is undercharged or has a leak. Under certain conditions it is
possible to see bubbles in the sight glass. Contact Cincinnati Sub-Zero if you have any questions.
Why do I smell something when I operate the chamber for the ! rst time at high
temperatures?
Cincinnati Sub-Zero chambers are cleaned and polished before leaving the factory. Stainless steel polish can
give off an odor while at elevated temperatures. This is a temporary condition and is non toxic.
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