3
APP-001f
SEPT 2016
The minimum line size for foul gas piping is ½” (13 mm).
The line should be pitched down toward the purger to
drain any refrigerant that may condense.
It is important that one purge point solenoid valve is
open at all times to prevent losing foul gas pressure to
the purger. The high side pressure transducer monitors
foul gas pressure and the AUTO-PURGER Plus will enter
an alarm condition if foul gas pressure is lost.
EVAPORATIVE CONDENSER PIPING
Typically, ammonia evaporative condenser outlet liquid
drain lines on each circuit must drop between 4’–6’ (1.2m–
1.8m) from the centerline of the condenser outlet to the
centerline of highest elevation of the liquid line manifold
to receiver. Preferably each circuit should have a P-trap
to balance variations in pressure drop in each circuit
and to prevent liquid from backing up into one or more
condensers, flooding the purge point. A properly-sized
equalizer line from the receiver will help drain condenser
circuits into the receiver. Refer to ASHRAE guidelines or
IIAR papers on condenser piping design. Also, consult
condenser manufacturer’s installation instructions for
additional piping and sizing information.
Do not use one purge point solenoid valve to purge two
circuits. This negates the P-trap on the condenser drain
line and may back liquid up into one circuit.
PURGE POINT LOCATIONS
Condensers should be purged at points recommended by
the condenser manufacturer. This is typically at the top
of each circuit’s outlet header.
In some cases a small, high-pressure auxiliary receiver
is located at the outlet of one or more condensers. This
receiver should have a purge point at the top.
Where a high-pressure float regulator is used to drain one
or more condensers, the top of the float valve chamber
should be a purge point.
Heat exchangers and horizontal shell and tube watercooled
condensers should be purged at the top, usually at the
point or points furthest from the compressor discharge
main inlet. Vertical condensers should be purged near
the top of the vessel if possible.
For certain types of oil separators where very low velocities
may exist near the top of the vessel, purging may be
advisable from a top fitting.
It is not necessary to purge control pressure receivers,
high pressure thermosyphon vessels, or vessels located
on the low side of the system.
CONDENSER
CONDENSER
CONDENSER
RECEIVER
AUTO-PURGER PLUS APP (ALL MODELS)
PURGE POINT SOLENOID
VALVE (TYPICAL)
LIQUID DRAIN LINE FROM CONDENSER
PITCH FOUL GAS LINES TOWARD PURGER
1/2" (13 MM) LINE SIZE UP TO 200–300 FEET (60–90 M)
3/4" (20 MM) LINE SIZE FOR LONG PURGE GAS LINES
OR WHERE TWO PURGERS ARE PURGING A
COMMON PURGE POINT
1/2" (13 MM) PORT
PURGE POINT
SOLENOID (TYPICAL)
(NO TRAP
S ALLOWED)
CONDENSER
INLET (TYPICAL)
PURGE POINT CONNECTION ON
TOP OF OUTLET PIPE OF EACH
CIRCUIT IN CONDENSER (TYPICAL)
PURGE POINT SOLENOID VALVE
(TYPICAL). LOCATE SOLENOID
VALVE NEAR THE PURGE POINT
AT THE SAME OR HIGHER
CONDENSER OUTLET (TYPICAL)
FOUL GAS LINE TO PURGER
1/2" (13 MM) LOW-PRESSURE PUMPED-LIQUID LINE
3/4" (20 MM) MINIMUM SUCTION LINE TO
PROTECTED SUCTION ACCUMULATOR
ELEVATION THAN THAT
OF THE PURGE POINT
1/2" (13 MM) LOW-PRESSURE LIQUID-RETURN LINE
TYPICAL PURGE POINT LOCATIONS
Figure 2
CONDENSER
CONDENSER
CONDENSER
RECEIVER
AUTO-PURGER PLUS APP (ALL MODELS)
PURGE POINT SOLENOID
VALVE (TYPICAL)
LIQUID DRAIN LINE FROM CONDENSER
PITCH FOUL GAS LINES TOWARD PURGER
1/2" (13 MM) LINE SIZE UP TO 200–300 FEET (60–90 M)
3/4" (20 MM) LINE SIZE FOR LONG PURGE GAS LINES
OR WHERE TWO PURGERS ARE PURGING A
COMMON PURGE POINT
1/2" (13 MM) PORT
PURGE POINT
SOLENOID (TYPICAL)
(NO TRAP
S ALLOWED)
CONDENSER
INLET (TYPICAL)
PURGE POINT CONNECTION ON
TOP OF OUTLET PIPE OF EACH
CIRCUIT IN CONDENSER (TYPICAL)
PURGE POINT SOLENOID VALVE
(TYPICAL). LOCATE SOLENOID
VALVE NEAR THE PURGE POINT
AT THE SAME OR HIGHER
CONDENSER OUTLET (TYPICAL)
FOUL GAS LINE TO PURGER
1/2" (13 MM) LOW-PRESSURE PUMPED-LIQUID LINE
3/4" (20 MM) MINIMUM SUCTION LINE TO
PROTECTED SUCTION ACCUMULATOR
ELEVATION THAN THAT
OF THE PURGE POINT
1/2" (13 MM) LOW-PRESSURE LIQUID-RETURN LINE
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SECTION 2 INSTALLATION
AUTO-PURGER PLUS APPT (ALL MODELS)
