LLC. Low Profile Unit Cooler Technical Guide

15
The hot gas defrost unit coolers conforms to
the standard 3-pipe hot gas system using a check
valve assembly, an electrical control to terminate
the defrost, and a hot gas solenoid valve. The
check valve assembly transports the hot gas
between the drain pan loop and the sideport
distributor of the coil. The check valve assembly kit
is available for shipped-loose or factory-installed
for an additional cost.
The electrical control option includes an
adjustable defrost termination and fan delay
control (DTFD) which is standard. An optional
(2) control electrical system is available with one
adjustable control for defrost termination (DT)
and one xed control for the fan delay (FD) for
an additional cost. For both the DTFD and DT
adjustable controls, the remote bulb position is
with the bulb strapped to the suction line to insure
a complete defrost. The remote bulb is positioned
by the installer. The hot gas solenoid valve must be
ordered separately and will be shipped-loose. The thermostatic expansion valve could be ordered separately and shipped-
loose or the thermostatic expansion valve could be factory-installed with a liquid line for an additional cost.
The liquid line is designed for the body styles of the Sporlan SQE, SBF, EG and the Alco HFESC thermostatic
expansion valves. The thermostatic expansion valve needs to be selected by the sales engineer. In a typical 3-
pipe, multiple evaporator system, the compressor discharge defrosts the evaporator. The liquid/vapor mixture of
refrigerant after defrost, however, returns to the common suction line of the system. In order to provide sucient
re-evaporation of the liquid vapor mixture and sucient heat for defrost, no more than one-third of the system
should be defrosted at one time. Some means of control in the 3-pipe hot gas system should be supplied to
regulate the large amount of liquid returning to the compressor, refrigerant slugging can otherwise damage
the compressor.
When using the hot
gas units with a hot
gas loop drain pan on
0°F applications and
below, an insulated
drain pan is required.
For hot gas models with the
hot gas loop drain pan only
Shipped-loose Factory-installed
TXV Liquid Line TXV Liquid Line
GLC 6 FPI SQE/SBF EG HFESC SQE/SBF EG HFESC
035-075
090-160
180-280
50169410
50169411
50169412
50169413
50169414
50169415
50169416
50169417
50169418
52733901
52733902
52733903
52733904
52733905
52733906
52733907
52733908
52733909
GLC 4 FPI
041-080
102-204
235
50169410
50169411
50169412
50169413
50169414
50169415
50169416
50169417
50169418
52733901
52733902
52733903
52733904
52733905
52733906
52733907
52733908
52733909
Shipped-loose Factory-installed
Drain Pan Loop Check Valve Kit Drain Pan Loop Check Valve Kit
GLC 6 FPI
035-075
090-160
180-280
50169504
50169505
50169506
52739601
52739602
52739603
GLC 4 FPI
041-080
102-204
235
50169504
50169505
50169506
52739601
52739602
52739603
3-Pipe Hot Gas Defrost