Tweco 400 Ultra-Cut(May 2014) - Manual (Page 204)

ULTRA-CUT 100 XT/200 XT/300 XT/400 XT
A-76 APPENDIX Manual 0-5302
Possible causes:
• Cooling fan(s) not operating.
• Disrupted air flow.
• Defective inverter module.
• Inverter Ribbon cable bad connection.
• Defective CCM.
Originally 100 and 200A units had 2 smaller fans while 300 & 400A used a single larger fan along with a larger radiator. More
recently, the single larger fan may be used in the 100 & 200A as well.
Troubleshooting:
1. Confirm that air is exhausting from both the top (top fan)and bottom (bottom fan of units with 2 fans) of the opening in
the right side panel. As the fan(s) are behind the radiator it’s hard to see them to confirm they are turning but perhaps
you can use an inspection mirror. Refer to section for code 403 for troubleshooting defective fans.
!
WARNING!
Fan blades can be moving and accidental contact with a mirror or other inspection devise can cause personal injury
or damage to the machine.
2. Leaving the side panels and cover off, especially the left lower side or the top cover will reduce the air flow. Also if the
radiator fins become clogged with dust it will reduce air flow. Clean the radiator periodically by blowing air into it to clear
dirt from the fins.
259-264 Inverter Over Temperature due to high Ambient.
The CCM measures the ambient temperature where the cooling air enters the louvers on the left side of the front panel. If
an inverter goes over temperature and we have determined that the ambient exceeds 40 deg C we will get one or more of
the high ambient codes, 252-264. The sensor, TS2, is a NTC (Negative Temperature Coefficient) resistor whose resistance
varies with temperature. It is mounted on the inside of the front panel next to the louvers on the left. To access it requires
removing one or more of the inverter modules. If the ambient is high but no inverter is too hot there is no fault.
Possible causes:
• Ambient is too high.
• Cooling fan(s) not operating.
• Disrupted air flow.
• TS2, Ambient temperature sensor, shorted (very unlikely) or otherwise defective.
• Defective Relay board.
• Defective CCM.
• Defective Relay board.
Troubleshooting:
1. If room temperature exceeds 40 deg C, cool the room, or operate the unit at reduced duty cycle or lower current.
2. Confirm that air is exhausting from opening in the right side panel. As the fan(s) are behind the radiator it’s hard to see
them to confirm they are turning but perhaps you can use an inspection mirror. Be careful not to get the mirror or your
hands into the blades. 100 & 200A units have 2 smaller fans, 300 & 400A have one larger one.
3. It is unlikely these high ambient temperature codes would be set before some other temperature related code but just in
case we’ll note that leaving the side panels and cover off, especially the left lower side or the top cover will reduce the air
flow. Also the radiator fins clogged with dust will reduce air.
4. To test TS2 remove J2 from the Relay board and measure the resistance between pins 4 & 6 of the J2 harness connector.
The resistance varies from about 33K ohms at 0 degrees C to about 12K ohms at 20C to 5.3K ohms at 40C.