KR Electrical Defrost Unit Coolers (PN E108318_S) 8
4 DRAIN LINE
The drain line should be as short and as steeply pitched as possible with a minimum of ¼” drop
per running foot. Any traps in the drain line must be in an ambient above freezing location. If the
temperature sur- rounding the trap or drain line is below freezing (32°F) it must be wrapped with a
drain line heater. Be sure to also wrap the unit drain coupling. Cover the drain line, drain coupling,
and heat tape with insulation. Be sure to follow the manufacturer’s recommendation when installing
the drain line heat tape.
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. Use two wrenches
when tightening to prevent the drain fitting from twisting and damaging the unit.
Long runs of drain line (i.e., more than a few feet) should be supported by hangers to avoid damage
to the drain pan.
5 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 for 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 toward the compressor. Vertical suction
risers may require a trap at the bottom of the riser for proper oil return.
There are two typical methods of defrosting a unit with hot gas. FIGUREs 7A. and 7B (in section 9
“Sequence of Operation”) show typical piping arrangements for 3 pipe hot gas defrost. FIGUREs
8A and 8B show typical piping arrangements for reverse cycle defrost.
For Food Service installations – seal any joint between unit cooler and cooler wall with a sealant
Listed by the National Sanitation Foundation.
Special Instructions for Units Using Carbon Dioxide (R-744)
These unit coolers are intended to utilize carbon dioxide only in a secondary loop or cascade
system. As such, unit installation must comply with the following instructions:
A.
If the refrigeration system is de-energized, venting of the R-744 through the pressure
regulating relief valves on the refrigeration system can occur. In such cases, the
system may need to be recharged with R-744, but in any case, the pressure regulating
relief valve(s) are not to be defeated or capped. The relief setting shall not be altered.
B.
A sufficient number of pressure relief and pressure regulating relief valves may need
to be provided based on the system capacity and located such that no stop valve
is provided between the relief valves and the parts or section of the system being
protected.
To properly protect and control systems using pumped liquid overfeed R-744, the solenoid,
isolation, and pressure relief valves shall be arranged as shown in either FIGURE 2 or 3,
according to the solenoid valve arrangement. To handle the requirements of liquid R-744 high
pressure solenoid valves are to be used.
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