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2-2
R
efRIgeRatIon
Line Sizing
Refrigerant lines should be sized as shown on
the refrigeration legend that is furnished for
the store or according to ASHRAE guidelines .
Refer to the information on the next page for
branch line piping of Hussmann Equipment .
Oil Traps
P-traps (oil traps) must be installed at the base
of all suction line vertical risers .
Pressure Drop
Pressure drop can rob the system of capacity .
To keep the pressure drop to a minimum, keep
the refrigerant line run as short as possible
using a minimum number of elbows . Where
elbows are required,
.
only
INSULATION
The suction and liquid lines should be clamped
or taped together and insulated for a minimum
of 30 ft (9144 mm) from the merchandiser .
Additional insulation for the balance of the
liquid and suction lines is recommended wher-
ever condensation drippage is
objectionable or lines are exposed to ambient
conditions .
SUCTION LINE
•
Pitch in direction of flow .
•
May be reduced by one size at one third of
case run load and again after the second
third . Do not reduce below the case suction
line size .
•
Case suction
lines should enter
at the top of the
branch line .
P/N 0453549_M
/ e
leCtRICal
use long rAdius elbows
Suction Line Return
Suction Line Return
U.S. & Canada 1-800-922-1919 • Mexico 1-800-890-2900 • WWW.HUSSMANN.COM
LIQUID LINE
•
May be reduced by one size after one half
the case run load . Do not reduce below the
case liquid line connection size .
•
Take-offs to case liquid lines should exit
the bottom of the branch liquid line .
Provide an expansion loop for each evap-
orator take-off . (Minimum 3 in . [76 mm]
loop .)
Minimum Loop
M inim um Loop
3-in. (78 mm)
3-in. (76 m m )
Liquid Line Take Off
Liquid Line Take Off
CONTROL SETTINGS
Merchandiser data sheets are shipped with this
manual . The data sheets provide case control
settings and defrost data .
An evaporator pressure regulator or EPR (pri-
mary control) and a 3 – 5ºF (1 .7 – 2 .7ºC) dif-
ferential thermostat (secondary control) must
control refrigeration temperature . The EPR
must be set to maintain the proper saturated
evaporator temperature as listed in the data
sheets . The thermostat must be set a couple
degrees colder than the discharge air tempera-
ture specified in the data sheets . The ther-
mostat will prevent product freezing should
the EPR temperature drift downward during
reduced load periods (lights off, lower ambi-
ent) . The thermostat will be wired to control
the compressor motor contactor (single com-
pressor) or a liquid line solenoid valve (parallel
compressor systems) .
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