Lincoln Electric LN-25 PRO DUAL POWER Service Manual page 30

B-12
1. GAS PURGE PUSHBUTTON
(See Figure B.4)
The gas solenoid valve will energize but neither the
power source output nor the drive motor will be turned
on. The Gas Purge switch is useful for setting the
proper flow rate of shielding gas. Flow meters should
always be adjusted while the shielding gas is flowing.
2. FLOW METER
The flowmeter shows the flow rate of shielding gas and
has a valve to adjust the flow. The flow meter is scaled
for CO , Ar, and Ar/CO blends. The middle of the ball
2 2
indicates the flow rate of shielding gas.
Adjust the flow rate while depressing the GAS PURGE
switch by turning the valve at the bottom of the meter.
Most weld procedures require 25-40 scfh (11.8 - 18.9
lpm) for sufficient shielding gas coverage. Gun angle,
nozzle diameter, joint configuration and wind condi-
tions may effect the amount of shielding gas required.
When using a wire feeder with a flow meter, adjust the
regulator at the shield gas bot-
tle or supply to a flow rate that
is higher than the flow rate
indicated on the feeder flow
meter. Note that most regula-
tors are calibrated based upon
having low restrictions on the
outlet. The valve on the feeder
flow meter creates a high
restriction and may cause
errors in the readings at the
supply regulator. Set the gas
flow rate using the feeder flow
meter reading and not the sup-
ply regulator reading.
SCFH Liter/Min.
10 4.7
20 9.4
30 14.2
40 18.9
50 23.6
60 28.3
70 33.1
80 37.8
OPERATION
90
80
70
60
50
B all
40
30
20
10
Valve
LN-25™ PRO DUAL POWER
B-12