Tweco 400 Ultra-Cut XT Plasma Cutting System - Manual (Page 221)

ULTRA-CUT 100 XT/200 XT/300 XT/400 XT
Manual 0-5297 APPENDIX A-87
Possible causes for low flow:
• Coolant filter clogged.
• Flow bypass valve incorrect adjustment or defective. Call the factory for instructions.
• Defective pump.
• Coolant supply or return hose twisted or pinched reducing flow.
If coolant flow is not low but code is being set, possible causes:
• Flow switch disconnected or defective.
• Relay PCB.
• CCM.
Troubleshooting:
1. First note whether the fault is an “E” meaning it’s currently low or an “L” meaning it was low but isn’t now.
Flow that remains low could indicate a failed component or a blockage such as clogged filter or pinched
hose. It also means you should be able to measure the flow to determine if it is really low or the sensor has
a problem.
2. First recycle power. If flow is still low or a component is defective the code should change to 404. Go to
that section for further troubleshooting.
3. If after recycling power there is no code, continue cutting to see if it occurs again. Take note of when it oc-
curs, for example if it’s with the torch at one end of the table, perhaps the leads get pinched there? In any
case go to code 404 section for more information.
403 Coolant overheated.
TS1 is a linear negative temperature coefficient (NTC) resistor sensor attached to the brass fitting at the exit of
the bypass valve. Here we determine the coolant being supplied to the torch is below the required temperature
which is currently 75 deg C (167F). The radiator is on the lower right side of the unit. The fan(s) are behind it
and blow out through the radiator. 100A & 200A units may either have 2 smaller fans or one larger one. The
300 & 400A units have one larger one.
Fans operate during cutting and for 4 minutes after last cut then shut off. Exception is AC 200 XT where the
fans are on whenever power is on. The external heat exchanger, HE400, fan is thermostatically controlled so it
only comes on when coolant is over 60 deg C. It will shut off when the other fans shut off.
Possible reasons for coolant overheated:
Coolant fan(s) failed or defective fan control relay MC2.
• Radiator fins clogged with dirt.
• Duty cycle exceeded (ambient temperature above 40 deg C and operating at high duty cycle).
• Operating with an object placed in close proximity to the air outlet (right side of the unit) or the front
panel inlet openings.
• Operating for extended time with right lower side panel removed.
• Defective Relay board.
• Defective CCM.