Heatcraft Refrigeration Products BN-LOPTB - 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
HGT 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
HGT  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
HGT 6 FPI
035-065
075-140
160-280
50169304
50169305
50169306
50169604
50169605
50169606
52733601
52733602
52733603
52733801
52733802
52733803
HGT  FPI
041
068-102
136-235
50169304
50169305
50169306
50169604
50169605
50169606
52733601
52733602
52733603
52733801
52733802
52733803
Hot Gas Reverse Cycle Kits