Installation, Operation, and
Maintenance Information
Low Velocity Unit Coolers
Bulletin No. IOM 110.3
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Table of Contents |
Inspection ................................................................................................................................................................................ |
2 |
Installation ....................................................................................................................................................................... |
2 – 4 |
General.................................................................................................................................................................................... |
2 |
Location............................................................................................................................................................................... |
2 |
Drain Line ............................................................................................................................................................................ |
3 |
Refrigerant Piping................................................................................................................................................................ |
3 |
Expansion Valve.................................................................................................................................................................. |
3 |
Evacuation........................................................................................................................................................................... |
3 |
Wiring ............................................................................................................................................................................. |
3 - 4 |
Typical Wiring Diagrams ................................................................................................................................................. |
4 |
Start-up Procedure.......................................................................................................................................................... |
5 – 6 |
System Check ......................................................................................................................................................................... |
5 |
Initial Start-up ...................................................................................................................................................................... |
5 |
Superheat Adjustment................................................................................................................................................... |
5 – 6 |
Maintenance..................................................................................................................................................................... |
6 – 7 |
General ................................................................................................................................................................................ |
6 |
Cleaning............................................................................................................................................................................... |
6 |
Check-up.............................................................................................................................................................................. |
6 |
Fan Blade and Motor Replacement ..................................................................................................................................... |
6 |
Defrost Heater Replacement ............................................................................................................................................... |
7 |
Troubleshooting Chart ......................................................................................................................................................... |
7 |
Replacement Parts ................................................................................................................................................................ |
8 |
Service Record ...................................................................................................................................................................... |
8 |
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Part # 08499173
INSPECTION
When the equipment is received, the number of crates and cartons should be checked against the bill of lading. Any damage or shortages should be noted immediately and a report given to the freight carrier and the manufacturer. It is the customer’s responsibility to file all freight claims with the carrier. Verify that the voltage listed on the unit nameplate matches the power supply available.
INSTALLATION
General
Installation and maintenance must be performed by qualified personnel who are familiar with the local codes and regulations and who are experienced with this type of equipment. When mounting the units, lift and handle them by the cabinet or hanger flanges only. Lifting by the tubing or fan guards may result in damage to the unit. The unit should be mounted level to ensure proper drainage. Caution: Avoid contact with sharp edges and coil surface as they are
potential injury hazards.
Location
Determine the best location for the unit cooler in the room to be refrigerated. Placement of the unit should be centered in the room and away from doors to keep warm, outside air from being drawn into the unit. This dual discharge unit draws air up through the fan blades and discharges it through the coil surface. Figure 1 shows the proper clearances that should be maintained for proper air flow and service access to the unit. Allow at least 36 inches space below the drain pan for air flow and service access. Before unit is raised into position all packaging should be removed while taking care not to damage the drain fitting or refrigerant connections. The unit should be supported on 5/16” minimum rod hangers, or 5/16” minimum lag bolts, at all mounting slots. To meet NSF requirements, the unit must be positioned flush with the ceiling and all gaps properly caulked. If hung below the ceiling, adequate space for cleaning must be provided per NSF requirements.
Dimension (Ft.)
A B C
Min. 5 10 2
Max. 15 30 10
Figure 1: Unit Location (Top View)
Drain Line
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Part # 08499173
The drain line should be pitched at a minimum of 1/2” per foot to allow proper drainage and should exit the refrigerated space as soon as possible. The drain line should be insulated and sealed to protect from freezing where it passes through the wall and a trap provided outside the refrigerated area. In rooms with temperatures below 34° F, the drain line should be heated and insulated.
Refrigerant Piping
Refrigerant piping should be installed in accordance with all applicable codes and using good refrigeration practices. For liquid and suction line sizing, refer to the ASHRAE Refrigeration Handbook. A trap must be installed prior to any risers in the suction line. Horizontal suction lines should be sloped at a minimum of 1/8” per foot to provide proper oil return to the compressor. Suction lines should be properly insulated to prevent sweating and higher return gas temperatures.
Expansion Valve
Expansion valves are to be sized and installed in accordance with the valve manufacturer’s recommendations. Valves should include an external equalizer line, which must be connected. Proper location of the sensing bulb is extremely important to the performance of the coil. Good thermal contact to the suction line is essential. On solder type valves, a wet cloth wrapped around the valve during installation will help protect it from overheating and damage during the installation process.
Evacuation
Proper evacuation is essential prior to charging the system. This avoids many problems that may arise due to lack of detail in this step. After charging, the system should be checked through all cycles to ensure proper operation. See Startup Procedure section in this bulletin.
Wiring
Wiring should be done in accordance with all national and local codes. Electric defrost units are supplied with a temperature sensing defrost termination switch which will terminate the defrost at a preset temperature. A fan delay switch is also provided to allow the coil to cool down prior to the fans restarting after the defrost cycle. The time clock should be adjusted to have a maximum 30 minute override to prevent overheating and steaming of the coils. Typically one to two defrosts per day are recommended however the number of defrosts are ultimately dictated by the usage of the box and the actual amount of frost buildup on the coils.
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Part # 08499173
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