Master-Bilt MUR Operator’s Manual

UNDERCOUNTER REFRIGERATORS

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 three 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 to
wire any unit. 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 cabinets, except for the Cold Wall version, 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.

During the operation of these units, frost will periodically form on the coil surface. Each time the refrigeration
compressor cycles to the “off” position, the evaporator fans and condenser fans will continue to run. This will
tend to keep the interior of the cabinet at a constant temperature and at the same time remove any frost build
up on the unit by circulating the inside air over the coil. The water produced will collect in the unit cooler drain
pan and travel down a drain tube to the condenser drain pan where the water will vaporize back into the air.

The refrigeration system is designed to provide a 38˚F temperature. The system employs a “constant cut-in”
control. This device accomplishes control of the interior by sensing the evaporator coil. Since the control
features a non-adjustable “cut-in” temperature of 38˚F, and the sensor tube is embedded in the fins of the
evaporator coil, nuisance coil icing is eliminated because the controller will not permit compressor start up unit
the coil reaches 38˚F. Adjusting the control knob on this system will adjust the “cut-out” temperature only. The
control knob on the refrigerator is located on the unit cooler front panel.

COLD WALL MODEL

The cold wall model employs evaporator tubing fastened to the outside of the interior sidewalls, back and top.
During the refrigeration process, heat is removed through the evaporator tubing and expelled through the
condensing unit. With this type of design, condensation may form on the interior of the cabinet and should be
periodically wiped dry. In order to assure proper air flow, make certain the flow of air behind the cabinet and
through the front louver is not restricted.

The refrigeration system on this cabinet uses a temperature thermostat that sense the cut-in and cut-out
temperatures of the cold wall evaporator coil. The temperature can be adjusted by turning the thermostat
control knob which is located behind the lower front panel

MAINTENANCE

PERIODIC CLEANING

Beginning with the initial installation, the interior surfaces of the cabinet should be periodically wiped down
with a solution of warm water and baking soda. This solution will remove any odors from spillage that may
have occurred. The exterior of the cabinet should also be cleaned frequently with a commercial grade of glass
cleaner, which will remove any fingerprints and help protect the surfaces.

Monthly cleaning of the condenser will aid the heat transfer characteristics of the refrigeration system and
increase its efficiency. To accomplish this, remove the cover panel from the cabinet and use a wire brush to
loosen any dirt particles that are attached to the fins. After this is accomplished, use a vacuum cleaner to
remove the loosened particles.

All moving parts have been permanently lubricated and will generally require no maintenance.

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