Rev. 0909
5
6 . Prevent condensate drains from freezing:
a. Do not install condensate drains in contact with
non-insulated suction lines. Suction lines should
be insulated with a nonabsorbent insulation
material such as Armstrong’s Armaflex.
b. Where condensate drains are located in dead
air spaces (between refrigerators or between a
refrigerator and a wall), provide means to prevent
freezing. The water seal should be insulated to
prevent condensation.
Refrigeration
Refrigerant type
The standard refrigerant will be R-404 unless otherwise
specified on the customer order. Check the serial plate on
the case for information.
Piping for more than one case on a condensing unit is run
underground with either common suction and liquid lines
from the machine room or individual suction and liquid lines
joined together in the machine room.
Refrigeration lines
LIQUID
SUCTION
3/8” O.D.
5/8” O.D.
note: the standard coil is piped at 5/8” (suction); however,
the store tie-in may vary depending on the number
of coils and the draw the case has. depending on the
case setup, the connecting point in the store may be
5/8”, 7/8”, or 1 1/8”. Refer to the particular case you are
hooking up.
Refrigerant lines should be sized as shown on the
refrigeration legend furnished by the store.
Install
P-tRaPS
(oil traps) at the base of all suction line
vertical risers.
Pressure drop
can rob the system of capacity. To keep the
pressure drop to a minimum, keep refrigerant line run as
short as possible, using the minimum number of elbows.
Where elbows are required, use long radius elbows only.
control Settings - Remote
See the MZ3-S Technical Data Sheet for the appropriate
settings for your merchandiser. Maintain these parameters
to achieve near constant product temperatures. Product
temperature should be measured first thing in the morning,
after having been refrigerated overnight. Defrost times
should as directed in the MZ3-S Technical Data Sheet.
The number of defrosts per day should never change.
The duration of the defrost cycle may be adjusted to meet
conditions present at your location.
control Settings-self contained
All functions are controlled by Omni-Stat Controllers. See
MZ3-S Technical Data Sheet for proper temperature and
defrost settings.
access to tX valves and drain lines
MECHANICAL
- Remove product from end of case.
Remove product racks. Remove refrigeration and drain
access panels (labeled). TX valve (mechanical only) and
drain are located under each access panel at end of the
case.
ELECTRONIC
- The Electronic Expansion valve master
and slave cylinder(s) are located within the electrical
access panel(s).
electronic expansion valve (optional)
A wide variety of electronic expansion valves and case
controllers can be utilized. Please refer to EEV and
controller manufacturers information sheet. Sensors for
electronic expansion valves will be installed on the coil inlet,
coil outlet, and in the discharge air. (Some supermarkets
require a 4th sensor in the return air). Case controllers will
be located in the electrical raceway or under the case.
thermostatic expansion valve location
This device is located on the same side as the refrigeration
stub. An Alco balanced port expansion valve model
is furnished as standard equipment, unless otherwise
specified by customer.
expansion valve adjustment
Expansion valves must be adjusted to fully feed the
evaporator. Before attempting any adjustments, make sure
the evaporator is either clear or very lightly covered with
frost, and that the fixture is within 10° F of its expected
operating temperature.
Measuring the operating Superheat
1. Determine the suction pressure with an accurate
pressure gauge at the evaporator outlet.
. From a refrigerant pressure temperature chart,
determine the saturation temperature at the
observed suction pressure.
3. Measure the temperature of the suction gas at the
thermostatic remote bulb location.
4. Subtract the saturation temperature obtained in step
No. from the temperature measured in step No. 3.
The difference is superheat.
5. Set the superheat for 5°F - 7° F
omni-Stat location
The Omni-Stat case controllers are located in the access
area in the right end panel. To gain access, remove the
right louvered panel. Please refer to the MZ3-S Technical
Data Sheet for the proper recommended temperature and
defrost settings.
Plumbing (cont'd)