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 10F T.D. and 95F 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 10F to 12F T.D. system, the valve should be adjusted to maintain 5F
to 6F superheat.
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