Heatcraft Refrigeration Products BN-LOPTB - Manual (Page 14)

1
In the refrigeration cycle, the thermostatic expansion
valve bypass assembly check valve only allows refrigerant
flow through the thermostatic expansion valve and into the
evaporator coil. As the refrigerant vapor exits the coil at the
suction line, the check valve of the drain pan loop check valve
assembly prevents the refrigerant vapor flow through the drain
pan loop.
Factory engineered assemblies (kits) are available for both
shipped-loose and factory-installed at an additional cost to
complete the reverse cycle piping and components. The suction
line check valve assembly includes the suction line check valve
and the piping for both the suction line and the connection
to the drain pan loop inlet header. In order for the suction line
check valve assembly to be mounted, the drain pan loop check
valve assembly must be used. The drain pan loop check valve
assembly includes the check valve, suction line tee and a bent
pipe. The thermostatic expansion valve bypass assembly option
includes the check valve, tee and necessary piping. In order for
the thermostatic expansion valve bypass assembly option to
be complete, a thermostatic expansion valve must be selected
by the sales engineer. The thermostatic expansion valve
bypass assembly option is dependent on the body style of the
thermostatic expansion valves which includes the Sporlan SQE,
SbF, EG and the Alco HFESC body styles. The factory-installed
thermostatic expansion valve bypass assembly option must
have the thermostatic expansion valve selection included on
the order for the hot gas unit cooler.
To increase the efficiency, higher performance and greater system protection, a heat exchanger may be beneficial to the
system. In order to use a heat exchanger, the thermostatic expansion valve bypass assembly option must be modified. See
the piping view in Figure 2. The modification includes rerouting the pipe from the thermostatic expansion valve bypass
check valve to the inlet connection of the liquid line to the heat exchanger. A pipe needs to be routed from the liquid line
outlet connection of the heat exchanger to the inlet connection of the thermostatic expansion valve.
The electrical control option includes an adjustable defrost termination and fan delay control (DTFD) which is standard.
For an additional cost, an optional (2) control electrical system is available with one adjustable control for defrost
termination (DT) and one fixed control for the fan delay (FD). For both the DTFD and DT adjustable controls, the remote
bulb position is with the bulb strapped to the piping of the thermostatic expansion valve bypass assembly option between
the distributor sideport and the check valve. When the thermostatic expansion valve bypass assembly is shipped-loose, the
installer will need to position the remote bulb. When the thermostatic expansion valve bypass assembly is factory-installed,
the remote bulb should already be properly installed.
Hot Gas Reverse Cycle Kits (cont.)