Hussmann Krack MS Series User manual

MS Series Medium Profile Unit Coolers (E270190_F) 1
1
Part Number: E270190_H

MS Series Medium Profile Unit Coolers (E270190_H) 2

MS Series Medium Profile Unit Coolers (E270190_H) 3
TABLE OF CONTENTS
1 UNIT INFORMATION AND DIMESIONS ............................................................................................................ 5
1.1 MODELS COVERED ____________________________________________________________________ 5
1.2 UNIT DIMESION _______________________________________________________________________ 6
2 RECEIPT OF EQUIPMENT..................................................................................................................................... 7
2.1 INSPECTION __________________________________________________________________________ 7
2.2 LOSS OF GAS HOLDING CHARGE ________________________________________________________ 7
3 ASSEMBLY OF COMPONENTS ............................................................................................................................. 7
3.1 SHIPPED LOOSE PARTS - LONG THROW ADAPTERS _______________________________________ 7
3.2 REFRIGERANT DISTRIBUTOR NOZZLES _________________________________________________ 7
3.3 EXPANSION VALVE____________________________________________________________________ 7
3.4 CHECK VALVE ________________________________________________________________________ 8
4 RIGGING INSTRUCTIONS ..................................................................................................................................... 8
4.1 RIGGING INSTRUCTIONS _______________________________________________________________ 8
5 UNIT LOCATION AND MOUNTING .................................................................................................................... 8
5.1 UNIT LOCATION _______________________________________________________________________ 8
5.2 MOUNTING ___________________________________________________________________________ 8
6 PIPING INSTALLATION ......................................................................................................................................... 9
6.1 DRAIN LINE ___________________________________________________________________________ 9
6.2 REFRIGERATION PIPING _______________________________________________________________ 9
6.3 EVACUATION AND LEAK TEST ________________________________________________________ 11
6.4 MS GAS DEFROST PIPING _____________________________________________________________ 111
6.5 REFRIGERANT DISTRIBUTOR NOZZLES _______________________________________________ 111
6.6 EXPANSION VALVE___________________________________________________________________ 13
7 ELECTRICAL ........................................................................................................................................................ 133
7.1 FIELD WIRING ______________________________________________________________________ 133
7.2 ELECTRICAL DATA __________________________________________________________________ 133
7.3 AIR DEFROST SEQUENCE OF OPERATION ______________________________________________ 144
7.4 ELECTRIC DEFROST SEQUENCE OF OPERATION ________________________________________ 166
7.5 HOT GAS DEFROST SEQUENCE OF OPERATION _________________________________________ 188
7.6 DUAL SPEED MOTOR – SEQUENCE OF OPERATION ______________________________________ 20
7.7 VARIABLE SPEED MOTOR – SEQUENCE OF OPERATION _________________________________ 21
7.8 VARIABLE SPEED MOTOR WITH SYSTEM 450 – SEQUENCE OF OPERATION ________________ 21
7.9 INTERLOCKING SINGLE COMPRESSOR UNIT WITH KRACK COILS _________________________ 22
8 START UP ............................................................................................................................................................... 233
8.1 PRE-STARTUP _______________________________________________________________________ 233
8.2 OPERATION CHECKOUT _____________________________________________________________ 233
9 PREVENTATIVE MAINTENANCE ................................................................................................................... 244
9.1 DRAIN PAN _________________________________________________________________________ 244
9.2 COIL AND CABINET __________________________________________________________________ 244
9.3 FAN GUARD OR LONG THROW ADAPTER REPLACEMENT _______________________________ 255
9.4 FAN REPLACEMENT _________________________________________________________________ 255
9.5 UNIT MOTOR REPLACEMENT _________________________________________________________ 255
9.6 ELECTRIC DEFROST HEATERS ________________________________________________________ 255
10 TROUBLESHOOTING CHART .......................................................................................................................... 266
11 REPLACEMENT PARTS LIST ........................................................................................................................... 266

MS Series Medium Profile Unit Coolers (E270190_H) 4
TABLES
TABLE 1 UNIT DIMENSIONS .................................................................................................................................................... 5
TABLE 2 CHECK VALVES KITS ................................................................................................................................................ 7
TABLE 3 DISTRIBUTOR NOZZLE CAPACITIES – TONS OF REFRIGERANT ................................................................... 122
TABLE 4 MS MOTOR ELECTRICAL DATA (AMPS) ............................................................................................................. 133
TABLE 5 (E) EDL HEATERS ELECTRICAL DATA ............................................................................................................... 144
TABLE 6 TROUBLESHOOTING .............................................................................................................................................. 26
TABLE 7 REPLACEMENT PARTS LIST ................................................................................................................................. 277
FIGURES
FIGURE 1 UNIT DIMENSIONS ................................................................................................................................................. 6
FIGURE 2 DRAIN LINE.............................................................................................................................................................. 9
FIGURE 3 PIPE JOINING .......................................................................................................................................................... 9
FIGURE 4 MULTIPLE UNIT COOLERS CONTROLLED BY A SINGLE SOLENOID ........................................................... 10
FIGURE 5 MULTIPLE UNIT COOLERS CONTROLLED BY MULTIPLE SOLENOIDS ....................................................... 10
FIGURE 6 GAS DEFROST PIPING DIAGRAMS ................................................................................................................... 111
FIGURE 7 AIR DEFROST WIRING MOTOR TYPE C ........................................................................................................ 155
FIGURE 8 AIR DEFROST WIRING MOTOR TYPE D ........................................................................................................ 155
FIGURE 9 AIR DEFROST WIRING MOTOR TYPE V ........................................................................................................ 155
FIGURE 10 ELECTRIC DEFROST WIRING WITH DEFROST TIMER MOTOR TYPE C ................................................... 177
FIGURE 11 ELECTRIC DEFROST WIRING WITH DEFROST TIMER MOTOR TYPE D ................................................... 177
FIGURE 12 ELECTRIC DEFROST WIRING WITH DEFROST TIMER MOTOR TYPE V .................................................... 177
FIGURE 13 (E) EDL ELECTRIC DEFROST WIRING 1 PH .................................................................................................. 178
FIGURE 14 (E) EDL ELECTRIC DEFROST WIRING 3 PH .................................................................................................. 188
FIGURE 15 (H) HGE (3 PIPE) HOT GAS COIL AND ELECTRIC DRAIN PAN WIRING ................................................... 199
FIGURE 16 (G) HGG (3 PIPE)/(K) KGG (2 PIPE) GAS COIL AND GAS DRAIN PAN WIRING ........................................ 199
FIGURE 17 (P) KGE (2 PIPE) COOL GAS COIL AND ELECTRIC DRAIN PAN WIRING ................................................... 20
FIGURE 18 WIRING DRAWING OF EVAPORATOR WITH SYSTEM 450 ............................................................................. 21
FIGURE 19 SETUP IN SINGLE COMPRESSOR UNIT(INTERLOCKING SINGLE COMPRESSOR UNIT KRACK COILS) 22
FIGURE 20 DUAL SPEED EVAPORATER COILS (INTERLOCKING SINGLE COMPRESSOR UNIT KRACK COILS) ..... 22
FIGURE 21 VS SPEED EVAPORATER COILS (INTERLOCKING SINGLE COMPRESSOR UNIT KRACK COILS) ........... 23
FIGURE 22 REPLACEMENT PARTS LIST .............................................................................................................................. 26

MS Series Medium Profile Unit Coolers (E270190_H) 5
1 UNIT INFORMATION AND DIMENSIONS
1.1 MODELS COVERED
MS Series medium profile unit coolers.
The MS series designed for walk-in coolers with ceiling heights of 10 to 14 feet that require high airflow.
The MS series handles medium to low temperature requirements and has three defrost options – air, electric and
hot gas. Consult the drawing that was sent with each unit to determine the temperature and defrost type.
Additional refrigerants are shown in the TABLE classified as Glide and Non-Glide for selection of two speed or
variable speed motors to meet DOE/NRCan regulations.

MS Series Medium Profile Unit Coolers (E270190_H) 6
1.2 UNIT DIMENSIONS
TABLE 1: UNIT DIMENSIONS
Fan Q-ty A B C
1
45.00
45.00
57.00
2
45.00
90.00
102.00
3
39.00
117.00
129.00
4 39.00 156.00 168.00
FIGURE 1: UNIT DIMENSIONS

MS Series Medium Profile Unit Coolers (E270190_H) 7
2 RECEIPT OF EQUIPMENT
2.1 INSPECTION
All equipment should be carefully checked for damage or shortages as soon as it is received. Each shipment
should be carefully checked against the bill of lading. If any damage or shortage is evident, a notation must be
made on the delivery receipt before it is signed and a claim should then be filed against the freight carrier.
2.2 LOSS OF GAS HOLDING CHARGE
Each unit cooler is leak tested, evacuated to remove moisture and then shipped with a gas holding charge.
Absence of this charge may indicate a leak has developed in transit. The system should not be charged with
refrigerant until it is verified that there is no leak or the source of the leak is located.
3 ASSEMBLY OF COMPONENTS
3.1 SHIPPED LOOSE PARTS - LONG THROW ADAPTERS
Long Throw Adapters are shipped loose. They should be mounted on the unit before the unit is installed. The
evaporator fan cabinet contains through-bolts with the threaded end pointing out away from the fan cabinet. The
bolts have two ½” nuts, flat washers, and a lock washer on them. Remove the outer most nut, lock washer, and
one flat washer on each bolt. Place Long Throw Adapter on the top bolts braced against the remaining flat
washer. While holding the adapter with one hand place the flat washers, then the lock washers, and then thread the
nuts on the top two bolts to hold the guard and adapter in place. Repeat procedure on the bottom two bolts. Secure
with a wrench.
3.2 REFRIGERANT DISTRIBUTOR NOZZLES
Direct expansion unit coolers are piped using a refrigerant distributor with a changeable nozzle design to equally
distribute refrigerant to each circuit of the evaporator coil. Distributor nozzles are installed at the factory.
The nozzles provided with the unit have been selected for design conditions of 10F T.D. and 95F liquid
refrigerant at the expansion valve inlet or the conditions supplied to the factory at the time of order. If the unit will
be operated at conditions that are substantially different from these conditions, it may be necessary to select a
different size nozzle. Contact the factory for advice.
The nozzle must be installed in the distributor or the auxiliary side connector before installing the expansion
valve. There are nozzle identification numbers stamped on one side of the nozzle. Be sure to insert the nozzle
into the distributor with these numbers visible in case identification is required later. The nozzle is held in place
by a retainer ring that is easily inserted or removed with a pair of needle nose pliers.
3.3 EXPANSION VALVE
Before mounting the unit, install the expansion valve and connect the equalizer tube. The expansion valve should
be installed directly to the distributor body or as close as possible with no elbows or bends. Locate the expansion
valve bulb on a horizontal length of suction line as close to the suction header as possible. Position the bulb in a
3, 4 or 8, 9 o’clock position (do not position on the bottom side of the pipe). Clamp the bulb down flush and tight
against the pipe and insulate. Never locate the bulb in a trap or downstream from a trap.
Expansion valves are adjusted at the factory prior to shipment. The setting will be correct for many applications,
but in other applications adjustments may be needed. It is important that the operation of the expansion valve be
checked after the system has balanced out at the desired room temperature. If the coil is being starved it is
necessary to reduce the superheat setting of the valve by turning the adjusting stem counter-clockwise. If the
superheat is too low it is necessary to increase the superheat setting of the valve by turning the adjusting stem
clockwise. It is recommended that for a 10F to 12F T.D. system, the valve should be adjusted to maintain 5F
to 6F superheat.

MS Series Medium Profile Unit Coolers (E270190_H) 8
3.4 CHECK VALVE
Check valves kit brazed to the pipe at the field, refer to FIGURE 6.
TABLE 2: CHECK VALVES KITS
Model
Check Valve Kit
Gas Inlet
Diam
eter
166, 178, 195, 212,
223, 239, 323, 356,
390, 424
CE269381
0.500
444, 445, 487, 502, 532
0.875
594, 602, 643, 669,
685, 710, 803, 858, 914
CE269382 0.875
4 RIGGING INSTRUCTIONS
4.1 RIGGING INSTRUCTIONS
MS units tend to be a long and heavy object. Jobsite requirements will affect the method of moving and lifting the
unit into place. Carefully consider the support that is required to lift and move the unit. Under no circumstances
should the shipping skid be used for lifting the unit. To ensure that the unit is not bowed or damaged when being
lifted into place from above, all leg or hanger points should be used. If the unit is being lifted into place from
underneath, a level support directly under all of the shipping legs is required to adequately steady the unit as it is
lifted to the hanger rods.
5 UNIT LOCATION AND MOUNTING
5.1 UNIT LOCATION
Unit coolers must be located to provide good air circulation to all areas of the cooler. The unit cooler should be
positioned to blow away from the wall and directed down an aisle rather than into and through shelves. For best
performance it is desirable to arrange the air discharge toward the door of the cooler to minimize the entrance of
warm moist air when the door is open. Light fixtures, shelving and product boxes must be located so that they do
not block the air intake or air discharge from the unit cooler.
IMPORTANT:
The coil face must be located a minimum of 27” from the wall to assure unrestricted air intake.
5.2 MOUNTING
Install the expansion valve and equalizer connection before hanging the unit cooler. See section 2.3.
The unit cooler should be suspended with 3/8” diameter rods. Rods should have double nuts on the top and
bottom. Adequate support must be provided to hold the weight of the unit.
The unit must be mounted so that the drain pan end is approximately 1” lower than the bottom of the electrical
end of the unit. If mounted to a level ceiling the hanging brackets provide the slope. Mount to ceiling with
hanging brackets provided. Suspended units must have sufficient clearance above the unit for cleaning the top.
Remove shipping legs after installation.

MS Series Medium Profile Unit Coolers (E270190_H) 9
6 PIPING INSTALLATION
6.1 DRAIN LINE
The drain line should be as short and as steeply pitched as possible with a minimum of ¼” drop per running foot.
A drain line trap should be installed to prevent warm moist air from migrating through the drain line. If the
temperature surrounding the drain line and trap is below freezing (32) it must be wrapped with a drain line heater
and insulation. Be sure to also wrap the drain pan coupling. The drain line heater must be energized
continuously. Be sure to follow the manufacturer’s recommendation when installing the drain line heat tape.
FIGURE 2: Drain Line
A union at the drain connection in the drain pan is recommended for ease of installation and future servicing. The
union should be located as close to the drain pan as possible, but outside the drain pan space. Use two wrenches
when tightening to prevent the drain fitting from twisting and damaging the unit.
Use drain line hangers to avoid damage to the drain pan with long runs of drain line, i.e. more than a few feet.
FIGURE 3: PIPE JOINING
6.2 REFRIGERATION PIPING
System design must conform to all local and national codes, laws and regulations applying to the site of
installation. In addition, the safety code for mechanical refrigeration, ASME B31.5, should be followed as a
guide to safe installation and operation practice.
Refrigerant line sizes and piping techniques should be obtained from the ASHRAE guide or equivalent reference.
Under no circumstances should the refrigerant connection size of the unit be used as the basis for sizing the lines.
The horizontal suction line should slope away from the unit cooler toward the compressor. Vertical suction risers
may require a trap at the bottom of the riser for proper oil return.
EVAPORATOR
DRAIN PAN
4" to 6"
DRAIN TRAP
CONDENSATE
DRAIN LINE
UNION
DRAIN LINE WRAPPED
WITH INSULATING MATERIAL
THERMOSTATICALLY CONTROLLED
HEATING CABLE
INSULATED
WALL
HEATING CABLE
POWER LINE
VAPOR SEAL THE
PIPE PENETRATION
AND AWAY FROM EVAPORATOR
SLOPE DRAIN PIPE DOWN
WITH ACCESS
( 1/4 INCH PER FOOT OF PIPE )

MS Series Medium Profile Unit Coolers (E270190_H) 10
When connecting multiple unit coolers in series using a common suction line, the branch suction lines must enter
the top of the common suction line. The branch lines must be sized for the evaporator capacity and the common
suction line to be sized for the total system capacity.
To properly protect and control systems using pumped liquid overfeed R744, the solenoid, isolation, and pressure
relief valves shall be arranged as shown in either FIGURE 4 or 5, according to the solenoid valve arrangement. To
handle the requirements of liquid R744 high pressure solenoid valves are to be used.
FIGURE 4: MULTIPLE UNIT COOLERS CONTROLLED BY A SINGLE SOLENOID
FIGURE 5: MULTIPLE UNIT COOLERS CONTROLLED BY MULTIPLE SOLENOIDS
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