Tweco 300 XT Ultra-Cut Plasma Cutting System - Manual (Page 180)

ULTRA-CUT 300 XT
�7� PPENDIX Manual 0�5�7�
d. If jumping TP3 to TP1 does not turn the fans on then the Relay board or the �0 pin ribbon cable pin 13 is at fault.
Art # 12313
MC3A
MC3B
M1
Torch Coolant Pump
1
2
3
J16
1 2 3 4
J13
(65B)
(66)
(67) (64B)
CHASSIS GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
J8
1
5
3
2
4
Coolant Pump Control
K5
MC3
Coolant pump Control
(163)
(162)
SA4
ARC_SUPPRESSOR
D27
24 VAC
Relay PCB
TP1 TP3
CCM I/O PCB
To test Pump relay jump TP3 to TP1.
+24
J4-13
230 VAC from T1
Coolant flows but flow is less than the required minimum:
Test and adjust the pump/bypass valve:
This test measures the “dead head” or blocked flow pressure at the rear panel coolant supply fitting. Perform
this test only after the coolant system is fully primed, that is after the coolant is circulated throughout the system
and is mostly free of bubbles. It requires a pressure gauge with #6 JIC fitting.
The gauge needs to be able to read at least 173 PSI. Remove the coolant supply hose and connect the pressure
gauge in its place. For the uto�Cut �00 XT connect the gauge in place of the torch coolant supply hose on the
torch connection bulkhead. This is a #5 JIC fitting.
NOTE:
Do not put the gauge in-line and attempt to pinch off the hose to block the flow. It is very difficult to totally block
the flow and failure to do so will result in incorrect setting of the bypass.
Turn the on the unit. You will have � minutes to perform the test/adjustment before the system times out with
a coolant flow fault. If that happens recycling the power gives you another � minutes.
1. The pressure on the gauge should be close to 173 (170�175) PSI. If it is the pump and the bypass are OK.
�. If the pressure is less than 173 PSI adjust the bypass screw clockwise to raise the pressure. If you can
change the pressure with the bypass screw but cannot reach 173 PSI it is likely the pump is worn out or
damaged. If the pressure does not change using the bypass screw it is likely the bypass is defective.
3. If the pressure is above 173 reduce the pressure by adjusting the bypass valve screw counter clockwise.
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.� l). Use a larger con�
tainer 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 adjust�
ment screw) see pressure test/adjustment above
• The pump is worn out (may be the case with an older unit).