Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 194)

ULTRA-CUT 400 XT
A-70 APPENDIX Manual 0-5306
Possible causes:
• Coolant is low
• Level switch defective, disconnected or installed upside down.
• Relay board defective or J7 disconnected.
• CCM defective.
Troubleshooting:
1. Confirm visually that the level switch float is below the coolant, if not add more coolant to the tank.
2. Check J7 on the Relay board.
a. If properly connected remove J7 and check continuity between pins 2 and 4 (pins 2 & 3 of J71 on the switch itself).
b. If no continuity at J71 on the switch, if it is still open, replace the switch.
3. If there was continuity at J7 plug it back in and measure voltage on pin 9 of the 40 pin ribbon cable (Relay board J4 to
CCM J23). Common is TP1 on either the Relay or the I/O board.
a. Pin 9 should be high, about +10 to +15V. If it’s not the relay board is bad or the ribbon cable is shorted.
b. To test the ribbon cable remove both ends, J4 on the Relay board and J23 on the I/O board and measure from pin
9 of the ribbon cable to both pin 8 and pin 10 of the cable. Both should be open. If not replace the ribbon cable.
Otherwise it’s the Relay board.
4. If pin 9 of the 40 pin ribbon cable was high in step 3.a the CCM is defective.
402 Low coolant Flow
The flow switch FS1 is positioned in series with the radiator where it measures the flow returning from the torch. The flow
switch serves two purposes, one to insure there is adequate flow for cooling needs and two, it insures the torch consum-
ables are in place so the negative output of the power supply is not exposed. This function is called “Parts in Place” or PIP.
The output cannot be enabled if parts are not in place. The normally open flow switch requires 0.7 GPM (2.65 liter/min.)
+/- about 10% to close.
When the system is turned on and enabled and fails to achieve proper coolant flow after 4 minutes code 404 will be set.
Getting code 402 means it initially had enough flow but something has caused the flow to be reduced. Listed here are things
that might happen during cutting to cause reduced flow. For other causes like component failures refer to code 404.
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 occurs, 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.