Tweco 151 with SL100SV - Manual (Page 88)

SERVICE 5-20 Manual 0-4691
5
B. Torch will not pilot; gas flows; AC and Gas indicators ON; TEMP and DC indicators OFF
1. Gas pressure is below torch minimum requirement (Minimum pressure for power supply operation is lower than
minimum required for torch operation.)
a. Adjust gas pressure per pressure setting label on power supply.
2. Power Supply RUN / SET switch in SET position
a. Place RUN / SET switch to RUN position.
3. Upper O-ring on torch head is in wrong position.
a. Remove shield cup from torch; check position of upper O-ring. Correct if necessary.
Upper Groove
with Vent Holes
Must Remain Open
Threads
Upper O-Ring
in Correct Groove
Lower O-Ring
Art # A-03725
C. Torch will not pilot; AC , GAS , and TEMP indicators ON
1. Air flow blocked
a. Check for blocked air flow around the unit and correct condition.
2. Unit is overheated
a. Let unit cool down for at least 5 minutes. Make sure the unit has not been operated beyond Duty Cycle limit. Refer
to duty cycle data in Specifications Section.
3. Input line voltage is low
a. Check and connect to proper input power line.
4. Faulty Temperature Sensor / Switch
a. Refer to Appendix 15, Main PC Board Layout. Check IGBT Heatsink Temp Sensor (TS1). Disconnect wire connector
P29 from terminal J29 on Main PC Board. Check connector pins 1 and 2 for 10K ohm (±25%) (at ambient temperature).
If resistance is not 10K ohm (±25%), replace TS1.
b. Check Inductor Temp Switch (TS2). Disconnect wire connector P32 from terminal J32 on Main PC Board. Check
connector pins 1 and 2 for at least 12K ohms. If resistance is less than 12K ohms, replace output inductor (L1). If temp
switch is open, replace Main PC Board.