Tweco 300 XT Auto-Cut 400V - Manual (Page 146)

AUTO-CUT 300 XT
A-�� APPENDIX Manual 0-5290
401 Coolant Level Low
The coolant reservoir (tank) has a normally open (tank dry) float type level switch, LS1. When the coolant
level in the tank is below about ½ full this fault will signal the need to add coolant. It will not stop the process
during a cut but will instead show the 405 fault as a warning. As soon as the cut stops it will not allow another
to start until the issue is corrected.
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 consumables 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 re-
duced. 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.