Master-Bilt MUF Installation Manual

UNDERCOUNTER FREEZERS

Installation, Operation and Maintenance Instructions

INSPECTION

When the equipment is received, all items should be carefully checked against the bill of lading to
insure all crates and cartons have been received. All units should be inspected for concealed
damage by uncrating the units immediately. If any damage is found, it should be reported to the
carrier at once and a claim should be filed with the carrier. This equipment has been inspected and
tested in the manufacturing facility and has been crated in accordance with transportation rules and
guidelines. Manufacturer is not responsible for freight loss or damage.

INSTALLATION

GENERAL

After the unit crate and base have been removed, locate the legs or casters found in the interior of
the cabinet. Attach the legs or casters to the unit base by screwing them into the same threaded
fittings that were used to secure the crate base to the cabinet. Insure that they are screwed all the
way into the base.

If for some reason the doors are not squared up on the cabinet, the doors can be adjusted. Opening
the door(s) and loosening the screws that hold both the top and bottom hinges to the cabinet can
accomplish this. After adjusting the door so that it is aligned correctly, tighten the screws to securely
hold the hinges in place.

LOCATION

The refrigeration system located at the bottom of the cabinet requires free air access for proper
operation. Important: The cabinet may be enclosed on two sides, however, there must be a
minimum four inch clearance from the back of the cabinet to a wall, and from the bottom of the
cabinet to the floor. This model cannot be operated without the legs or casters in place, and
the bottom of the cabinet cannot be enclosed. The cabinet should be level when it is placed in
its permanent location.

ELECTRICAL

Check the proposed outlet to be used to insure that the voltage, phase and current carrying
capacity of the circuit from the electrical panel correspond to the requirements of the cabinet. Never
use an extension cord. All inter wiring between the electrical panel and the unit must be done in
accordance with the National Electric Code and all state and local codes. See the Serial Tag for all
pertinent electrical information.

Observe all Warning Labels. Disconnect power supply when servicing equipment to
eliminate injury from electrical shock or moving parts.

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OPERATION

FORCED AIR UNIT COOLER MODELS

The undercounter series of freezers employ a unit cooler evaporator located inside the cabinet as
the heat-removing source. Through the refrigeration process, heat is captured in the evaporator,
transferred to the condensing unit located at the bottom of the cabinet, and expelled to the
surrounding outside air. It is extremely important to maintain the minimum four-inch clearance as
described in this manual under “Location” for the refrigeration process to function properly. The
cabinet cannot be operated without the legs or casters installed.

After shutting the door on these freezer models, a short amount of time must be allowed before the
door can be reopened. This is due to the tight seal maintained between the door and the cabinet.
Waiting a few moments for the pressure to equalize permits the door to be opened easily.

With this freezer unit, a positive defrost is required to remove frost from the coil. This is
accomplished by energizing heaters positioned on the coil surface. The time clock, refer to Figure 1,
is factory set to allow four defrosts per day. Note: Setting the correct time of day will be required

to maintain these defrost periods.

When the preset defrost time is reached, the time clock automatically terminates the refrigeration
process by turning off the condensing unit and unit cooler fan motors, and energizes the defrost
heaters. As the coil temperature increases, the frost begins to melt producing water that runs down
the coil to the unit cooler drain pan and exits through the drain tube to the vaporizer. After all the
frost has been removed and the coil temperature reaches approximately 50˚F, the defrost is
terminated through the action of the defrost termination control located on the unit cooler, and the
refrigeration process resumes. In order to insure that any excess water remaining on the coil is not
sprayed into the cabinet interior, and all heat generated by the defrost is removed, the unit cooler

fans will not operate until the coil temperature reaches approximately 25˚F.
ADJUSTMENTS

The timer switch is located behind the lower front panel. Remove the
retainer screw and move the time forward to allow for adjustment.

1. Time clock adjustments:
Setting the correct time of day – To set the correct time of day,
simply rotate the small inner-dial counterclockwise until the correct
time of day on the large dial is opposite the “time” indicator. In
referring to the drawing of the time clock, the correct time of day
shown is 8:00 a.m.

Number of defrosts per day – The time is factory set to defrost the evaporator at 2:00 a.m., 8:00
a.m., 2:00 p.m., and at 8:00 p.m. The four settings should provide adequate defrosting for even
the most heavily used system. If more defrosts are required, remove a knurled slotted screw
from the holder, insert the screw into the time slot on the large dial where a defrost is desired,
and tighten. Insure that an equal time exists between each defrost pin. If experience shows that
the four set defrost periods are more than necessary, one or more of the knurled setscrews may
be removed. At least one of the knurled setscrews must be located on the large lower dial

at all times.

Fail Safe Feature – On the small, upper dial there is a pointer that is used to set a 100% fail­safe feature. The fail-safe of the timer is factory set at 30 minutes, indicating that the system will
revert to cooling thirty minutes after a normal defrost cycle began should a malfunction occur.

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