Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 196)

ULTRA-CUT 400 XT
A-72 APPENDIX Manual 0-5306
b. If 24 VAC is not on the MC2 coil check for D24 on the relay board being ON. If it’s on, the Relay board should be
providing the 24 VAC so if it’s not the Relay board must be defective.
c. If D24 is not on, measure on the CCM I/O board between TP2 and the common at TP1. It should be low, near zero
volts. If not the CCM is probably defective. Jumper TP2 (I/O board) to TP1. If the fans now come on replace the
CCM.
d. If jumping TP2 to TP1 does not turn the fans on then the Relay board or the 40 pin ribbon cable pin 19 is at fault.
404 Coolant System Not Ready
When power is applied to the system with External Plasma Enable satisfied and Plasma Power Supply Enabled (switch on
2010 or TSC 3000), assuming there is enough coolant in the tank, after some initial tests taking about 15-20 seconds (see
manual section 4 for details of the Start-Up Sequence) the pump will start. Coolant will be pumped through the system. Flow
is measured by the FS1 flow switch placed in the torch coolant return path just before the radiator (see plumbing diagram).
If the flow doesn’t reach at least 0.75 GPM (2.8 lpm) within 4 minutes it will set the 404 fault. The reason for the 4 minutes
is a new dry system especially one with long torch leads will take some time before the leads, hoses, radiator and cold plates
are full of coolant. More coolant may have to be added. On a system that has been run before it normally takes only a few
seconds to establish proper flow. In any case the pump will run for 4 minutes before setting the 404 fault.
First determine if the pump motor is running and if so is there any coolant flowing. With the right lower side panel removed
touch the pump and feel for vibration to indicate if the motor is running. Observe the clear coolant hoses to see if they are
full of coolant. There are two hose fittings on the back of the tank. The upper one is the coolant return. Remove the tank
filler cover. You should see a fairly strong stream of coolant from that fitting. The lower fitting is from the pump bypass
valve. If the pump is operating some coolant may be exiting that fitting as well. If these fittings are below the coolant level
you may have to drain out some of the coolant to see this. If a strong stream is exiting the bypass (lower) fitting but nothing
from the upper fitting, you probably have some kind of blockage.
Reasons for 404 faults (Coolant not flowing):
• In new installation, coolant has not circulated all the way through the leads. Add more coolant if necessary and recycle
the power to restart the pump and 4 minute timer.
• Coolant supply & return leads are reversed, check valve in torch coolant return prevents reverse flow.
• Torch parts removed or are wrong style so torch check valve shuts off flow.
• Torch coolant tube damaged or the tube extension (if required) missing.
• No power to pump motor.
• Pump/motor failure.
• Bypass valve defective or adjusted incorrectly.
Damaged Coolant Tube
Coolant tube includes a check valve at its upper end. When cartridge with consumables is not installed the spring loaded
coolant tube is fully extended closing the check valve preventing coolant from leaking out.
When consumables are in place they push the tube inward, opening the check valve, allowing coolant to flow. The coolant
tube has fingers on the end to contact the inside of the electrode and allow coolant to flow through the openings between
the fingers.
The fingers can be bent over or broken if reasonable care is not taken when the cartridge is not in place. If the fingers are
bent or broken it shortens the tube so the consumables may not push the tube in enough to open the check valve resulting
in no coolant flow. The coolant tube assembly may be replaced separately from the torch head.
Some consumables use an extension on the coolant tube. A missing extension will not allow the check valve to open.
Art # 12312
Coolant Tube Extension
Fingers
Internal Check Valve