Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 198)

ULTRA-CUT 400 XT
A-74 APPENDIX Manual 0-5306
Coolant flow test:
In addition to the pressure test or in place of it if you don’t have a gauge, determine if the flow returning from the torch (the
flow that passes through the FS1), is greater than the required minimum. With the unit switched off remove the return hose
from the back of the power supply. Place it in a container of a known volume. Turn the unit on and let the pump run exactly
30 seconds. It should pump at least 3/8 gal. (1.4 l). Use a larger container in case the flow is greater and it overflows.
If the flow is lower than 0.75 GPM:
• Look for restrictions such as sharp bends or something pinching the coolant hoses or torch leads.
• Other possibilities are the bypass valve has been adjusted wrong (someone may have turned the adjustment screw)
see pressure test/adjustment above
• The pump is worn out (may be the case with an older unit).
Coolant flow is correct but system doesn’t detect it due to defective components:
• Defective or disconnected FS1 flow switch.
• Relay board.
• CCM.
Flow Switch FS1 disconnected – FS1 comes with wire about 1 ft. long and a connector that connects to a 3 wire harness.
This could be disconnected at either end, J74 or J5 on the relay board.
Defective FS1– The flow switch, normally open, closes when flow through it exceeds 0.75 GPM, could be open. Easiest place
to measure the switch is at the J5 harness connector that plugs into the Pilot board. Assuming you have previously deter-
mined flow is sufficient, disconnect J5 from the Pilot board, start the unit so the coolant is flowing and measure continuity
between the 2 pins of J5.
• If there is no continuity either the switch is open or the harness between J5 and J74 at FS1 is open.
• If there is continuity between the J5 pins with sufficient coolant flow then either relay board or the CCM is faulty.
• Relay board
• CCM
405 Low Coolant Level Warning
If the coolant level becomes low while cutting it is not necessary to immediately stop the cut as there is still enough coolant
to continue so we display E405 as a warning. Once the cut stops if the coolant is still low the display changes to E401 and
prevents starting another cut. Refer to the section for code 401 for troubleshooting.
406 Coolant Flow Low Warning
Ultra-Cut XT units, in addition to a coolant flow switch, include a turbine flow sensor FL1, referred to in the plumbing diagram
as a “bubble sensor”, with a pulse output that accurately measures coolant flow and in addition can detect the presence of gas
bubbles in the coolant. Gas bubbles from leaking seals in the torch or hose fittings have been proven to reduce consumable
life. This code is a warning, it does not prevent cutting but if it persists the cause should be investigated.
407 Coolant Overheated due to High Ambient
As described in the section for codes 259-264 the CCM measures the ambient temperature using sensor TS2 and, like with
the inverters, if the coolant is over temperature we first check the ambient and if it is above 40 deg C we attribute the cause
of the coolant over temperature to high ambient and of course the solution is to lower the ambient or reduce the duty cycle.
The other possibility is the ambient measuring circuit is defective and the coolant is overheated. In that case you would
have to go to the section for code 403 to find the cause of the coolant overheating and go to section for codes 259-264 to
determine what is wrong with the TS2 circuit.