Tweco Troubleshooting Power Supply - Manual (Page 37)

37
Coolant not overheated but code 4-3 still set:
• Coolant temperature sensor circuit open
• PCB5
• CCM
Failed fan – Check for 24 VDC at fan connector, if present replace fan.
Open Coolant sensor – Temperature sensor has leads about a foot long with a
connector which connects to a 2 wire harness going to PCB5 CN1. If either end is
not connected gives 4-3 fault.
Coolant sensor measures about 20-25K ohms at room temperature. Resistance
reduces as temperature goes up. If resistance measures considerably more than
25K the sensor is defective.
PCB5 – Voltage at CN1-1 should be +15VDC. At room temperature the voltage
at CN1-2 is about 2.5-3 VDC. It increases at higher coolant temperatures. Voltage
out of PCB5 on the CN11 / J36 pin 7 is about 1.5-2 VDC at room temp. It is
scaled by the circuits on PCB5 so that 0-10V = 0 to 100 deg C. If the sensor
measures the correct resistance and either voltage at CN1 or at CN11 / J36 is
wrong then PCB5 is defective.
CCM – If voltages are correct on PCB5 then the CCM is at fault.
4-4
Cooling System not Ready
When power is applied to the system with External E-Stop satisfied and Plasma
Power Supply Enabled (switch on GCM 2000, 2010 or remote HMI) system goes
into the purge state. During purge gasses flow and the coolant pump operates.
Pump runs for up to 30 seconds during which it must see flow greater than 0.35
gal/min for at least 5 seconds. If it does not, it sets 4-4 code. When first installing
a system or new (dry) torch leads it is normal to have this happen until coolant has
circulated throughout the system.
Reasons for Cooling System not Ready code.
Coolant not flowing:
• In new installation, coolant has not circulated all the way through the
leads.
• 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.
• No power to pump motor.
• Pump/motor failure.