Heatcraft Refrigeration Products Air Defrost RLC - Manual (Page 13)

13
The hot gas unit coolers can be used in reverse cycle hot gas defrost systems using multiple evaporators
connected to one condensing unit. Generally, not more than one-third of the system defrosts at one time.
During the reverse cycle defrost, the reversing
valve; located in the compressor discharge
line, diverts hot gas through the suction line
to the evaporator. See piping view in Figure
1. The suction line check valve directs the hot
gas through the drain pan loop which prevents
condensate in the pan from freezing. The hot
gas exits the loop at the pan loop outlet header
and enters the evaporator through the check
valve assembly. As the hot gas defrosts the coil,
heat is removed from the hot gas and eventually
it condenses into a liquid and exits the coil at
the distributor sideport. The liquid then flows
through the check valve of the thermostatic
expansion valve bypass assembly, around the
thermostatic expansion valve, and into the
system liquid line. The liquid refrigerant then
feeds other evaporators on the cooling cycle,
evaporates, and returns to the compressor
through their suction lines.
Recommendation is that both check valve kits are ordered: (For hot gas models with the hot gas loop drain
pan ONLY)
NOTE: The drain pan check valve kit can be ordered as an independent item. But the suction line check valve kit
must be ordered with the drain pan check valve kit in order to complete the piping.
NOTE: 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.
Shipped-loose Factory-installed
TXV Bypass Assembly Kits TXV Bypass Assembly Kits
GLC 6 FPI SQE/SBF EG HFESC SQE/SBF EG HFESC
035-075
090-160
180-280
50169210
50169211
50169212
50169213
50169214
50169215
50169216
50169217
50169218
52733701
52733702
52733703
52733704
52733705
52733706
52733707
52733708
52733709
GLC 4 FPI
041-080
102-204
235
50169210
50169211
50169212
50169213
50169214
50169215
50169216
50169217
50169218
52733701
52733702
52733703
52733704
52733705
52733706
52733707
52733708
52733709
Shipped-loose Factory-installed
Drain Pan Loop
Check Valve Kit
Suction Line
Check Valve Kit
Drain Pan Loop
Check Valve Kit
Suction Line
Check Valve Kit
GLC 6 FPI
035-065
075-140
160-280
50169304
50169305
50169306
50169604
50169605
50169606
52733601
52733602
52733603
52733801
52733802
52733803
GLC 4 FPI
041
068-102
136-235
50169304
50169305
50169306
50169604
50169605
50169606
52733601
52733602
52733603
52733801
52733802
52733803
Hot Gas Reverse Cycle Kits