Thermo Scientific Harris Ultra-Low Temperature Freezers
Installation and Operation
3
4.6 Compressor Mounts
Some Harris DLTs are shipped with the compressor mounts
secured. The springs under the compressor mounting feet are
fully compressed by hold-down nuts for shipping.
These nuts
must be loosened before the unit is put into operation
(refer to
Figure 2).
To loosen the compressor mount springs, complete the following
steps:
1. Remove the end panel on the right side of the machine
compartment to expose the compressor.
2. Use a 3/4 in. box end or socket wrench with ratcheting handle
and a 4 in. extension to loosen the nuts on the compressor
mounts (refer to Figure 2). Loosen the nuts until the
clearance between the bottom of the nut and the top of the
mounting foot is 1/8 in.
3. Inspect the area under each mounting foot for spacer clips.
Any clips must be removed before compressor operation.
Figure 2. Compressor Mount Springs
Note:
Some of the Harris DLT freezers require loosening the
compressor bolts. This is not necessary for all models.
4.7 Pressure Equalization Port
When an upright ultra-low temperature freezer door is opened,
room temperature air rushes into the storage compartment.
When the door is closed, the fixed volume of air is cooled rapidly.
Pressure drops below atmospheric pressure, resulting in a
substantial vacuum. Re-entry into the cabinet is impossible until
internal pressures are returned to atmospheric pressure. Without a
pressure equalization mechanism, it can take several minutes
before the door can easily be reopened.
All upright models feature a port that provides vacuum relief
after door openings.
The pressure equalization port is located in the bottom left side of
the storage chamber. Although the port is designed to self-
defrost, excessive frost accumulation in the bottom of the
chamber could eventually restrict air flow. Therefore you should
periodically inspect the port and brush away any loose frost using
a stiff nylon brush.
WARNING!
To ensure proper operation, be sure not
to obstruct the port. Push any storage racks near the
port all the way to the rear of the cabinet.
WARNING!
When the freezer is in operation, avoid
touching the lower left side of the cabinet exterior near
the “hot surface” warning label. The port can get hot
immediately after it is activated.
Spring
