Neutronics H1301 - Inlet Pressure Switch Function and Adjustment

Model H1301 Recovery and Recycling System
Installation, Operation and Maintenance Manual
Revision-L September, 2019
Page 28 of 105
V. System Operations and Controls (continued)
C. Inlet Pressure Switch Function and Adjustment
There are two automatic modes of recovery: liquid recovery and vapor recovery.
During the liquid recovery mode the AGENT liquid containing dissolved nitrogen is
forced into the machine from the pressure of the nitrogen charge in the source container.
During the vapor recovery mode the AGENT vapor and free nitrogen gas is drawn into
the system using the vapor compressor of the machine. This evacuation process will
continue until the source container is emptied to (–10”) Hg vacuum level.
The inlet pressure switch is the sensor that determines whether the machine will
operate in the liquid recovery mode or the vapor recovery mode. When the pressure
of the source container is above the set point of the inlet pressure switch; the machine
will operate in the liquid recovery mode. When the pressure of the source container
drops below the set point of the switch; the machine will operate in the vapor recovery
mode. The factory setting of the inlet pressure switch is for Halon 1301 or FE25 set
at 90 to 100 psi.
AGENT source containers pressurized to 360 psi with nitrogen, when properly positioned
to discharge liquid first, will usually discharge all of the liquid AGENT with 90 psig of
AGENT vapor and nitrogen remaining in the container.
The machine will recover in the liquid mode until the pressure in the source container
drops below 90 psig then the machine will operate in the vapor recovery mode. Recovery
from source containers super pressurized with nitrogen will usually require no
adjustment of the inlet pressure switch from the factory set point.
The factory setting of 90 psig should always be used when processing Halon 1301
or FE25.
The inlet pressure switch will need adjustment when recovering Halon 1211 or
FM200 from source containers with a low nitrogen charge, (less than 200 psig), or
no charge at all. These container pressure conditions will present liquid AGENT to the
inlet of the machine below 90 psig at ambient temperatures. Unless the pressure switch
is adjusted to below the vapor pressure liquid AGENT will be drawn into the machine
during the vapor recovery mode. The machine will begin a self-evacuation process to
clear the liquid from the inlet plumbing preventing the vapor compressor from becoming
damaged. During the self-evacuation process the machine will not recover Agent
from the source container until the inlet plumbing of the machine is cleared of liquid.
This will greatly slow down the recovery process. The self-evacuation mode can be
identified when the control panel Compressor Lamp is illuminated while the Evacuation
Lamp is not illuminated. Normally both lamps will be illuminated simultaneously.
The condition of the source containers of agent must be evaluated and the inlet
pressure switch may be adjusted using the adjustment procedure beginning on the
following page. The source container may also be charged with nitrogen within the
limits of the working pressure of the container to avoid pressure switch adjustment.