Thermo Scientific Revco ExF-86C Operating Manual page 28

Vacuum Relief Port
(continued)
Thermo Scientific
The time required to draw 1.5-3.0 cu.ft. of air into the cabinet depends on
two factors:
a) the size and number of paths available for the air to enter the
cabinet, and
b) the pressure difference between the internal cabinet and the
ambient room.
Cabinets with the vacuum relief port operating normally, (i.e. vacuum
relief port is not iced over) will require a minimum of 30 seconds up to a
maximum of 120 seconds for the cabinet to equalize. This is also a good
indication that the exterior door is well sealed.
The vacuum relief port requires routine maintenance. It will ice over
unless preventive measures are taken. If the vacuum relief port becomes
iced over, the freezer will take several hours to equalize pressure.
Warning Do not leave the freezer unattended while the door is unlatched.
The vacuum could release, resulting in a door opening and product loss.
Observe the inner side of port periodically for frost and ice build-up.
Remove any frost with a soft dry cloth. If the tube should become clogged
with ice, it must be cleaned. Make sure during cleaning that the vacuum
relief tube is completely free of ice to prevent rapid ice formation.
Factors that can affect the performance of the vacuum relief port include:
high ambient temperature, high humidity conditions and frequent door
openings. Maintenance should be performed weekly or as needed.
Warning Failure to maintain the vacuum relief port may result in excessive
ice build up inside the tube, clogging the port, and inability to open the
door. The vacuum relief port may need to be cleaned more often with
frequent door openings and high humidity environments.
Section 4
Maintenance
s
s
Revco ExF 4-5