OXWELD PM-GST, Instructions Manual, Page: 3 / 8

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NOTE: The optimal amount of preheat oxygen is auto-
matically regulated by the torch. The pilot oxy-
gen valve is used only to adjust the pilot flame.
Cutting: Preheating is done while cutting lever is fully
depressed. Position torch on the far side of steel to be
cut. While maintaining at least 4 in. nozzle-to-work stand-
off, position the flame on the edge of the steel. Pull torch
towards you to begin cutting.
NOTE: The flame is hottest at the edge of the cutting
oxygen stream. Placing the edge of the cutting
oxygen stream on the edge of the steel will give
the fastest starts.
Torch head, nozzle, and nozzle nut become VERY
hot while pilot flame is on and remain hot for sev-
eral minutes after torch is turned off. Do NOT allow
hot torch to contact anything flammable.
SHUTTING OFF
1. Release cutting oxygen lever.
2. Close the pilot oxygen and fuel gas valves.
If operations are to be stopped for a half-hour or more,
pressure should be released from all regulators in the
following order:
1. Close station valve of each gas supply.
2. Open all torch shutoff valves.
3. When pressure on each regulator gauge drops down
to zero, back out regulator pressure-adjusting screw.
4. Close torch shutoff valves.
OPERATING PRECAUTIONS
Flow: There must be proper flow of gases for safe op-
eration and full performance. This requires the following
three conditions: (1) the regulators that determine the
inlet pressure to the hoses must be set to the correct
pressure: (2) the hoses and their connectors must have
adequate capacity for the job (hoses that are too long,
too small or have connectors with small passageways
can cause problems); and (3) the throttle valves on the
torch must be adjusted with the procedure shown in these
instructions.
NOTE: Items (1) and (2) can be checked by measuring
the gas pressures at the torch. Gauge adaptors
are available for this purpose.
Backfire: Improper operation of the torch may cause
the flames to go out with a loud “pop”. Such a backfire
may be caused by contact of nozzle with the work, by
the use of incorrect gas pressures or by leakage at the
cutting nozzle seats due to dirt or nicks on the seats or
to a loose nozzle nut.
ADJUSTING GAS PRESSURES
1. Depress the cutting lever fully. Adjust cutting oxy-
gen regulator to the desired pressure (see Figure 1)
compensating for any line loss to the torch through
the hose and valve. Then immediately release the
lever.
2. Adjust fuel gas regulator to provide 20 psig at the
torch with flow.
TESTING FOR LEAKS
The system should be thoroughly tested for leaks after
it is first hooked up, and at regular intervals thereafter.
With the system pressurized down to the shutoff valves,
apply Leak Test Solution suitable for oxygen service,
such as P/N 998771 (8 oz. container), on all joints and
connections. Bubbling of the solution indicates leakage.
If leakage is detected, tighten the connection. If this does
not stop leakage, then shut off the appropriate gas sup-
ply and open the torch valve to remove pressure from
the system. Break the leaky connection, wipe metal seat-
ing surface with a clean dry cloth, and examine them for
nicks and scratches. Remake the connection(s) and re-
test. Do not try to light the torch until you are satisfied
that all connections are gas tight.
After lighting the torch and adjusting the flames, use leak
test solution to check for leakage around hose connec-
tions at each valve and torch fitting.
LIGHTING AND FLAME ADJUSTMENT
Lighting Pilot Flame:
Open fuel gas valve fully and light
the gas about 2 inches from the nozzle with a friction
lighter. DO NOT use a match. Use of a match can seri-
ously burn your hand. Slowly open the pilot oxygen valve
until the pilot flame is adjusted as desired. For best per-
formance, a flame extending just beyond the nozzle skirt
is recommended.
Cutting Flame Adjustment: While torch is lit in pilot
mode, point torch in a safe direction, hold torch firmly
and depress cutting lever fully. CAUTION: The torch will
tend to kick back from the force of the cutting oxygen.
Adjust fuel gas valve to give desired flame. Release cut-
ting lever to return to pilot mode. Depress cutting lever
several times, both slowly and quickly to ensure pilot
flame is set properly. If torch extinguishes itself when
lever is released, open pilot oxygen valve slightly to in-
crease pilot oxygen flow, relight torch and readjust pilot
oxygen valve.
stream of the regulator. Tighten the connecting nuts
firmly using two wrenches to prevent damage to the
torch.
3. Assemble desired nozzle (see Table) to the torch
and tighten nozzle retaining nut firmly.
Never touch the nozzle to the work piece.