Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
5690002-2EN Revision 4
Object ID: 00000018WIA30A1AE20GYZ
Topic ID: id_13106501 Version: 2.4
Date: Oct 11, 2021 6:34:13 PM

HEC Troubleshooting

This document describes the various problems and conditions for the heat exchanger cabinet (HEC) and the possible solutions for those problems and conditions.

Note:

(For HEC G6000EN) For internal wiring and plumbing schematics, see GEHC DVMR HEC Heat Exchanger Cabinet Liquid Cooling System Manual, DOC1806874, available from the online documentation library. The G6000EN HEC can be identified by the features shown in Figure 1.

(For HEC G6001EN) For internal wiring and plumbing schematics, see GEHC DVMR HEC Heat Exchanger Cabinet Liquid Cooling System Manual, DOC1816671, available from the online documentation library. The G6001EN HEC can be identified by the features shown in Figure 2.

1	HEC catalog number G6000EN	3	Chilled air mixing valve
2	GC/PE mixing valve	4	No G-catalog label

1	HEC catalog number G6001EN	3	Chilled air mixing valve
2	GC/PE mixing valve	4	Catalog label G6001EN

Notice

Avoid leaks by checking that the bleeder valves on the front of each pump in the bottom of the HEC are fully closed before powering on the pumps for the first time.

Table 1. HEC Troubleshooting

For this condition:

Follow these steps:

Difficulty navigating or interpreting HEC screens.

Section 5.3 of Heat Exchanger Theory describes how to navigate the screens. Procedures for setting parameters for the HEC are described in subsequent sections of that document.

The HEC display shows zero cryogen compressor coolant flow, despite customer coolant flowing through the HEC and the cryocompressor receiving adequate flow.

Perform a TPS reset. If the cryogen compressor flow continues to show zero, the flowmeter in the HEC may be clogged or defective. It can be visually inspected by swinging the power box out of the way (see applicable steps in Power Box replacement procedure).

The HEC display shows dashes instead of values for gradient or power electronics coolant flow.

Check the red VFD display of the pump on the circuit in question. Make sure the display is not dark and that the circuit breaker it is not turned off.

If the VFD display is turned on, the issue is probably with the PE or GC pressure sensors.

If the HEC display shows either the gradient or power electronics coolant flow value, the sensor for the value shown is functioning. Swap the PE (J4) and GC (J3) pressure sensors at the signal box, and see if the values change.
The pressure sensors are FRUs, and are listed in the FRU manual.
Check the wire crimps at the connectors of any suspected faulty sensors.

The system displays messages saying that the HEC coolant reservoir is low. The HEC display appears to confirm this.

There are upper and lower pressure-sensitive level sensors mounted on the right side of each reservoir tank. These sensors close (turn on) when the coolant level is high (usually three inches above the sensor, but sometimes the height must be as high as five inches above the sensor).

You can measure the switch continuity with a digital multi-meter (switch closed, low resistance/switch open, very high resistance).

Add coolant to the reservoir until the coolant level is six to seven inches above the sensors. See HEC Coolant Fill and Coolant Leak Check. PE or GC should stop reporting the warning when the increase in coolant pressure causes the switches to engage.

Rarely, the pressure sensors become stuck. Stuck sensors can be freed by tapping them with a finger. Do not use anything other than your finger to tap the sensors.

The system displays messages saying coolant resistivity is too low.

The system reports a warning when resistivity falls below 3.5 kOhm-cm and inhibits scanning if below 2.5 kOhm-cm.

Deionize the coolant to restore the proper resistivity. See Heat Exchange Cabinet Coolant Deionization.

Note:

Generally, new systems will register around 5-15 kOhm-cm. However, it is possible for a system to have and display a coolant resistivity between 0.01 kOhm-cm and 1000 kOhm-cm, so it is possible that a new system will have a resistivity lower than 2.5 kOhm-cm and will not be able to scan. The solution is to deionize the coolant.

Performing deionization process, but resistivity value reported from HEC LCD is slowly going down or not changing.

Notice

Stop the process! Disconnect the inlet line before the tank overflows.

There are two possibilities:

The inlet line has been incorrectly connected to the facility coolant discharge and facility coolant is backflushing into the GC coolant tank.

Review Heat Exchange Cabinet Coolant Deionization, and after the configuration has been corrected, continue with the deionization process and confirm during the process that the GC coolant resistivity increases.
Coolant may not be flowing properly through the deionization kit.
- Check that the pump is primed and that coolant is flowing through the kit.
- Check that the kit connection at the reservoir quick disconnect is not constricting flow. Return any kits with poor flow for repair.
- Confirm that new filters are used in the DI kit.

The system displays pressure or RF air temperature warning errors.

Any deviations from specifications for pressure or cooling are stored in the system error log.

See the Facility Coolant Requirements section of Direction 5670003 Discovery MR750w 3.0T Preinstallation Manual for the HEC pressure and cooling requirements.

If the system returns error 2268904 or 2268905:

This error is displayed if the temperature exceeds the upper temperature limit or falls below the lower temperature limit. These are ±2 °C from a set point of 18 °C.
See the HEC block diagram. The temperature sensor that is detecting this error is located in the top manifold of the chilled air HEC blower assembly. This sensor rarely fails.
This error occurs commonly if the facility coolant cooling capacity is inadequate. Check the facility parameters on the HEC to make sure they are within specification. Facility coolant that is too cold is almost as problematic as coolant that is too warm. The coolant temperature MUST remain within the required upper and lower window requirements as stated in the Preinstallation Manual for the system.

Note:
See Heat Exchanger Theory for more information about navigating the HEC screens.
1. From the main menu of the HEC LCD screen, select Monitor > Facility.
2. Record the Facility Temperature, Inlet Pressure, and Differential Pressure values.
3. See the Facility Coolant Requirements section of Direction 5670003 Discovery MR750w 3.0T Preinstallation Manual for the HEC pressure and cooling requirements.
4. If the facility parameters do not meet specifications, have the customer fix the coolant flow or temperature issue. (The inline filter may require replacement.)
5. If the facility parameters meet specifications, check the mixing valve values:
  1. From the main screen of the HEC LCD display, select Diags > PID Monitor.
  2. Record the Blower Mixing Valve Percent Open value.
  3. Typically, this valve is at around 50% open. If the value is significantly below 50%, confirm that facility coolant temperature is not too low. If the value is significantly above 50%, check that facility coolant temperature is not too high and also check for adequate blower air flow. It is often necessary to seek assistance from the HVAC team that maintains the chiller to get facility coolant temperature under control. Call the OLC before ordering any parts for this problem.
6. If the facility parameters are within specification and the mixing valve is operating normally:
  1. Check to see whether the error condition always corrects within 1 to 3 seconds, or whether a TPS reset is always needed to correct the error condition.
    
    If either of these conditions is true, contact the OLC and request that the cooling.xml file be examined for spiking.
  2. Check Guided Install and make sure the correct HEC type is selected. (See the Guided Install screen for help in identifying the HEC type, or refer to Customer-Supplied Coolant, the Temperature section, in Heat Exchanger Theory. If the wrong HEC type was selected, make the proper selection and perform a TPS reset.

Refer to the Lytron vendor manual (GE PN 5161931) for vendor specifications.

Suspected bad pressure sensor.

It is important to determine whether the sensor or the signal box (PLC) is actually faulty.

If you are testing an HEC facility coolant inlet or outlet sensor:

Note the facility inlet and outlet pressure readings on the HEC LCD screen.
Swap J5 and J6 on the signal box and confirm that the facility inlet and outlet pressure readings are swapped on the HEC LCD screen. If they are swapped, the sensor is faulty.

If you are testing a GC pressure sensor:

Note the GC inlet pressure reading on the HEC LCD screen.
Swap J3 and J6 on the signal box and confirm that the same pressure reading for Facility Inlet Pressure on the HEC LCD screen.

If you are testing a PE pressure sensor:

Note the PE inlet pressure reading on the HEC LCD screen.
Swap J4 and J6 and confirm the same pressure reading for Facility Inlet Pressure on the HEC LCD screen.
Note:
Alternatively, you can test GC and PE pressure sensors by swapping J4 with J5 (Facility Outlet Pressure) instead of swapping J4 and J6.

One or both of these errors appear repeatedly in the error log, but scanning is not inhibited:

Heat Exchanger Cabinet (HEC) detected the gradient coil coolant flow is too low. Verify that the pump is turned on, and all inline valves are open.

Heat Exchanger Cabinet (HEC) detected the power electronics coolant flow is too low. Verify that the power electronics pump is turned on, and all inline valves are open.

The HEC may have pumps from different manufacturers (Price or Ebara). Confirm the pump type is exactly matched with the correct VFD chip.

An incorrectly matched pump and VFD chip results in either high pressure or low flows, risking equipment damage and/or system errors.

Ebara pumps have a round face; Price pumps have an irregular face. Do not rely on the color of the suction hose for identification. (Ebara pumps may have blue or white suction hoses.)
Confirm the pump speeds. For the speeds for each combination of GC/PE pump and RF amplifier, please see below.
The Eaton VFD requires a jumper wire between terminal 8 and 16 to set the correct speed for the Ebara pump.

Note:

A jumper wire is not used with the Price pump.

Note:

These speeds must be verified with the HEC in full-power mode (scan-ready). If you are unsure if the HEC is in full-power mode, prescribe an exam on the MR system to ensure the pumps are ramped to full speed.

Pump type (identify as described above)

Ebara

Price

RF amplifier type in PGR cabinet. Identify by presence of red and blue cooling hoses hooked to front of RF amplifier. Hoses are not present on air cooled RF amplifiers.

Liquid

Air

Liquid

Air

Displayed value on middle VFD (VFD PPMP)

50 ±1

43 ±1

61 ±1

53 ±1

Displayed value on left VFD (VFD GPMP)

50 ±1

61 ±1

Verify that PE pressure is 4.2 to 4.8 bar. Verify that GC pressure is 5.2 to 5.3 bar.

If the pressure is outside the stated limits, replace the pressure sensor.

Do not change any adjustable valve positions for less than maximum flow.

One or both of these errors appear repeatedly in the error log, but scanning is not inhibited.

Heat Exchanger Cabinet (HEC) detected the gradient coil coolant flow is too high.

Heat Exchanger Cabinet (HEC) detected the power electronics coolant flow is too high. Verify that the power electronics pump is turned on, and all inline valves are open.

The HEC may have pumps from different manufacturers (Price or Ebara). Confirm that the pump type is exactly matched with the correct VFD chip.

An incorrectly matched pump and VFD chip results in either high pressure or low flows, risking equipment damage and/or system errors.

Ebara pumps have a round face; Price pumps have an irregular face. Do not rely on the color of the suction hose for identification. (Ebara pumps may have blue or white suction hoses.)
Confirm the pump speeds. For the speeds for each combination of GC/PE pump and RF amplifier, please see below.
The Eaton VFD requires a jumper wire between terminal 8 and 16 to set the correct speed for the Ebara pump.

Note:

A jumper wire is not used with the Price pump.

Note:

Pump type (identify as described above)

Ebara

Price

RF amplifier type in PGR cabinet. Identify by presence of red and blue cooling hoses hooked to front of RF amplifier. Hoses are not present on air cooled RF amplifiers.

Liquid

Air

Liquid

Air

Displayed value on middle VFD (VFD PPMP)

50 ±1

43 ±1

61 ±1

53 ±1

Displayed value on left VFD (VFD GPMP)

50 ±1

61 ±1

Verify that PE pressure is 4.2 to 4.8 bar. Verify that the GC pressure is 5.2 to 5.3 bar.

If the pressure is outside the stated limits, replace the pressure sensor.

Do not change any adjustable valve positions for less than maximum flow.

Suspected bad temperature sensor.

It is important to determine whether the sensor or the signal box (PLC) is actually faulty.

If you are testing the HEC facility coolant inlet sensor:

Note the Facility inlet temperature reading on the HEC LCD screen.
Note the GC inlet temperature reading on the HEC LCD screen.
Note:
The HEC stops pumping when the GC sensor is disconnected. Pumps will restart when the sensor is reconnected.
Swap J18 (Facility) and J17 (GC) on the signal box, and confirm that the facility temperature is now visible for GC on the HEC LCD screen, and that the GC temperature is now visible for Facility on the HEC LCD screen.

If you are testing the GC temperature sensor:

Note the Facility inlet temperature reading on the HEC LCD screen.
Note the GC inlet temperature reading on the HEC LCD screen.
Note:
The HEC stops pumping when the GC sensor is disconnected. Pumps will restart when the sensor is reconnected.
Swap J18 (Facility) and J17 (GC) on the signal box, and confirm that the facility temperature is now visible for GC on the HEC LCD screen, and that the GC temperature is now visible for Facility on the HEC LCD screen.

If you are testing the PE temperature sensor:

Note the Facility inlet temperature reading on the HEC LCD screen.
Note the PE inlet temperature reading on the HEC LCD screen.

Note:
The HEC stops pumping when the PE sensor is disconnected. Pumps will restart when the sensor is reconnected.
Swap J18 (Facility) and J16 (PE) on the signal box, and confirm that the facility temperature is now visible for PE on the HEC LCD screen, and that the PE temperature is now visible for Facility on the HEC LCD screen.

If you are testing the Blower temperature sensor:

Note the Facility inlet temperature reading on the HEC LCD screen.
Note the Blower inlet temperature reading on the HEC LCD screen.
Move the connector at J18 (Facility) to J28 (Blower) on the signal box, and confirm that the blower temperature is now visible for Facility temperature on the HEC LCD screen.
Note:
You can move the connector at J28 to J18 to make the temperature check the other way. However, this may require cutting the tie wraps for the J28 cable to reach the J18 connector.

Circuit breaker trips when power is applied to the HEC. Circuit breaker or fuses in MDP may trip at same time.

Examine the HEC for short circuits:

Perform LOTO on the HEC. See the MR Service Safety Manual, PN 5452735.
Open the HEC power box, and disconnect pump or blower wiring from the VFD.
Use a DVM to measure resistance between the pump or blower lines (phase-to-phase) and from each line to ground (phase-to-ground) for short circuits.
Use a DVM to measure resistance between the VFD input and output connections (phase-to-phase) and from each line to ground (phase-to-ground) for short circuits.
Use a DVM to measure resistance between the BLW CB circuit breaker input and output connections (phase-to-phase) and each connection to ground (phase-to-ground) for short circuits.

If there are no short circuits observed, order and replace the HEC power box.

There is insufficient water flow to or from components in the PGR cabinet.

Check for kinks in the supply and return hoses, especially where hoses are behind units. You can often quickly clear a kink by twisting a pressurized hose a full rotation in one direction and then twisting it in the opposite direction.

Use a discharge hose and a flask or bucket as troubleshooting tools to check for coolant flow on the supply and return hoses and through components.

Notice

Use the Coolant Draining Kit that is shipped with the HEC (and available as a FRU) to drain PGR modules. Do not use any pump other than the supplied hand pump.

Notice

The water cooling system for the PGR cabinet is rated to 65 psi.

Use a high volume pump to try to clear blockages in components. Try the return side first, then the supply side. You may need to repeat this a few times to clear the blockage.

Notice

Use the Coolant Draining Kit that is shipped with the HEC (and available as a FRU) to drain PGR modules. Do not use any pump other than the supplied hand pump.

Check that ball valves and check valves in the cooling lines from the HEC are open and installed in the correct orientation. Make sure fittings are fully engaged on each component in the PGR cabinet

HEC pumps are constantly cycling on and off.

The HEC stops pump operation if GC or PE coolant temperature sensors report measurements that are over the limits. This can be due to the heating of the pipe while the pump is dry or the flow of coolant is stalled. Check for any obstructions (kinks, twists, etc.) in the coolant line or improper installations (backwards check valve) or closed ball valves (tank valve, external valves, etc.).

Need to view HEC parameters in real-time.

The system uses event-based polling to monitor the HEC, storing the data it receives to the cooling.xml log file.

Open a C-shell and type:

more /usr/g/service/log/paramdata/cooling.xml

Each output describes units in which the value is expressed. You must pay attention to the units and scaling.

At power up, the GC/PE coolant pump or blower is not operating. The Lenze AC Tech VFD for the component displays UF.

At initial start or after replacing the GC/PE coolant pump, air needs to be purged from the system. This is done automatically by running the pump, but the pump may need to be cycled on several times before this process completes successfully.

The run command is not being sent from the signal box.

Both of these conditions are corrected by sending run commands from the signal box using the following steps:

Notice

Do not cycle pumps rapidly on and off using the circuit breaker, because VFD damage may result. Use the shortcut keys from the signal box controller as described below.

On the signal box controller, hold the up arrow button while you press F1 to toggle the blower on, F2 to toggle the GC pump on, and F3 to toggle the PE pump on.
If the VFDs do not ramp up to the proper speed, check the connections at the side of the signal box and check for a bad VFD.
If all appears okay, replace the signal box.

After initial power up, the system reports the GC coolant resistivity is out of range (too low or too high).

If the GC resistivity value is less than 2.5 kOhm-cm and greater than 1 kOhm-cm, deionize the coolant. See Heat Exchange Cabinet Coolant Deionization.

A GC resistivity value greater than 20.0 kOhm-cm may mean that an FE forgot to add rust inhibitor and biocide chemicals after performing the last deionization procedure. Perform deionization again and ensure these are added according to the procedure. If values are unchanged after adding additives, then proceed to “If the fuse is OK” section below.

A GC resistivity value less than 1 kOhm-cm may indicate faulty hardware.

Make sure a successful TPS reset has been done since initial system power up.
Remove the HEC signal box cover and check the condition of the fuse located in the upper left corner of the DI circuit board. A spare fuse is usually provided in the plastic bag inside the signal box. If a fuse is not available, order 5266827 Fuse FRU kit.
If the fuse is open:
1. View the voltage selector toggle switch setting through the view holes on the front of the HEC power box. You may need a flashlight.
2. Confirm that the switch is in the correct position for incoming voltage to the HEC. See Section 4.3 of Power-On Sequencing.
If the fuse is OK:
It is likely that the signal box has malfunctioned. Order both a signal box and a DI sensor. Try replacing the sensor first.
Multiple instances of an open fuse indicate variations in one or more incoming AC line phases. If the toggle switch is in the correct position, and the AC line phase voltage variation is within the product’s published limits, replace the power box.

The cable dressing for the HEC signal box appears different.

There are two versions of the cable dressing for the HEC signal box. The newer version is used in HEC version 11 and higher and signal box version 2 and higher.

To determine the version of the HEC, locate the rating label for the HEC behind the left front door on the floor of the cabinet.

To determine the version of the signal box, locate the label on the side of the signal box. If there is no label, the signal box is an early model.

The mixing valve reading on the signal box LCD screen is at 100% or 0%.

A reading of 100% means:

The maximum amount of coolant is being passed through the heat exchanger.
The mixing valve is completely open (down):
- (For HEC G6000EN) The stem on the mixing valve is completely down so that the stem is almost flush with the mixing valve case.
- (For HEC G6001EN) The actuator is completely down.
1 Mixing valve for HEC G6000EN 3 Valve stem
2 Mixing valve for HEC G6001EN 4 Actuator

A reading of 0% means:

The minimum amount of coolant is being passed through the heat exchanger (the maximum amount of coolant is being passed around the heat exchanger).
The mixing valve is completely closed:
- (For HEC G6000EN) The stem of the mixing valve is at the maximum height above the mixing valve case.
- (For HEC G6001EN) The actuator is completely up.

Mixing valve positions (0% to 100%) does not have any significant effect on total facility coolant flow through HEC, because these are three-way valves so the same amount of coolant passes through the cabinet regardless of valve position.

HEC blower circuit breaker trips and needs to be manually reset.

The blower may be drawing excess current because of a blockage.

Check the condition of the air filter on the PEN wall in the scan room. Clean or replace if it is dirty.
Inspect the area where the filter is located and make certain that it is not too restricted so that air flow into the filter is poor.
Inspect the blower motor or hosing inside the HEC for evidence of excessive amounts of dust or lint.

Additionally, there are hoses internal to the HEC that connect to the blower. It may be necessary to remove the suction hose (the one not connected to the liquid-to-air heat exchanger) and check if the internal wall of the hose is still intact and not delaminated or clogging airflow.

Coolant to PE or GC components is too cold or warm (HEC does not appear to be regulating temperature of coolant).

(For HEC 6000EN only) Inspect the top of the mixing valves and make sure that nothing like a hose, cable, etc. is depressing the white plastic manual override button on top of the mixing valve.
Check the mixing valve percentages on the HEC LCD screen. Contact OLC if necessary for support.

On power up, Lenze AC Tech VFD displays two-letter code such as UF.

On the signal box controller, hold the up arrow while you press F1 to toggle the blower on, F2 to toggle the GC pump on, and F3 to toggle the PE pump on.
If there is no response, cycle HEC power and try again to start the pumps manually (hold the up arrow while you press F1 to toggle the blower on, F2 to toggle the GC pump on, and F3 to toggle the PE pump on).
If you cannot clear the code, try these solutions:
- Check for proper incoming AC mains power.
- If the code is visible only on a single VFD, swap its control wiring with that of neighboring unit and see if the problem moves.
- If the same code is visible on all VFDs, and incoming AC mains power is okay, check operation of the signal box.

Eaton VFD displays power fault two-letter code F1 09 – Reset/clear power fault

DETAILS: After mains power interruption, the VFD will lock out in an error condition, displaying F1 09. The reset/clear power feature allows the VFD to ramp to a safe powered down condition to protect the load device (motor). A TPS Reset will not recover the VFD from this condition. Follow this process to manually clear the error message and reset the pump or blower.

Turn off the circuit breaker (group of 3) in the HEC power box supplying power to the drive showing the fault. For instance, if the VFD GPMP has the fault, turn off the GPMP circuit breaker only, the remaining circuit breakers are left on: PWR CB, PPMP CB, BLW CB, and CRY CB
Allow time for the VFD display to turn off.
Turn the circuit breaker back on.
Cycle the drive command for the pump or blower by simultaneously pressing:
- (For the GPMP (gradient pump)) Up arrow + F2 (see Illustration 1)
- (For PPMP (power electronics pump)) Up arrow + F3 (see Illustration 1)
- (For BLW (blower)) Up arrow + F1 (see Illustration 1)
  Figure 3. HEC Drive Command
This will restart the “Run” command from the drive.
The drive will reset and the pump or blower in question should function normally.

Note:

To avoid future power faults, make sure to perform the following steps for “Restart Programming” as well.

Eaton VFD displays power fault two-letter code F1 09 – Restart Programming for the HEC Power Box

DETAILS: After mains power interruption, the VFD will lock out in an error condition, displaying F1 09. The restart programming feature allows the VFD to ramp to a safe powered down condition to protect the load device (motor). A TPS Reset will not recover the VFD from this condition. Follow this process to change the Auto-Restart setting, parameter P6.13, allowing TPS reset to start the pump and blower.

If the drive shows a fault, follow the steps listed in the row above.
Disable the drive command at the signal box for the pump or blower by simultaneously pressing:
- (For the GPMP (gradient pump)) Up arrow + F2 (see Illustration 2)
- (For PPMP (power electronics pump)) Up arrow + F3 (see Illustration 2)
- (For BLW (blower)) Up arrow + F1 (see Illustration 2)
  Figure 4. HEC Drive Command
This will remove the ‘Run’ command from the drive, displaying 0.0 Hz on that drive.
Press the button on the VFD labeled “BACK RESET” (1). This will activate the menu level (arrow flashes).
Figure 5. Eaton display
1. Back/Reset button 2. Up arrow button
3. Ok button 4. Down arrow button
Using the ‘down arrow’ button (4), press until the arrow on the left of the display moves from ‘MON’ to ‘PAR’. Press the ‘OK’ button (3). When the PAR menu is activated, the first parameter will flash between ‘P1.1’ and ‘0’ on the display.
Press and hold the ‘up arrow’ button (2) until parameter P6.13 is shown. This is the setting for Automatic Restart. The display will alternately flash between ‘6.13’ and ‘0’.
Press the ‘OK’ button (3). The display will show current setting ‘0’. Press the ‘up arrow’ button (2) to change the value to 1. Press the ‘OK’ button (3). This enables auto-restart.

Note:
Complete this step quickly, otherwise the system will timeout.
Press the ‘BACK RESET’ button (1), and then press the ‘up arrow’ button (2) until the arrow on left of display is next to MON. Press the ‘OK’ button (3). This completes the parameter change actions.
In order to restart the drive at the signal box, manually cycle the drive command for the pump or blower by simultaneously pressing:
- (For the GPMP (gradient pump)) Up arrow + F2 (see Illustration 4)
- (For PPMP (power electronics pump)) Up arrow + F3 (see Illustration 4)
- (For BLW (blower)) Up arrow + F1 (see Illustration 4)
  Figure 6. HEC Drive Command
This will enable the “Run” command from the drive.
The drive will restart and the pump or blower will function normally:
- (For the GPMP (gradient pump)) 61 Hz ± 5 Hz. (active mode), 43 Hz. ± 5 Hz. (idle mode)
- (For PPMP (power electronics pump)) 61 Hz ± 5 Hz. (active mode), 43 Hz. ± 5 Hz. (idle mode)
- (For BLW (blower)) 60 Hz ± 5 Hz. (active mode only)
Repeat Step 2 – Step 8 until all 3 VFD’s have been updated.

Table 2. AC Tech VFD Fault Messages
Fault	Description	Possible Cause
AF	High Temperature	Ambient temperature is too high; the cooling fan has failed (if equipped).
CF	Control Fault	A blank EPM or an EPM with corrupted data has been installed.
cF	Incompatibility Fault	An EPM with an incompatible parameter version has been installed.
dF	Dynamic Braking Fault	The drive has sensed that the dynamic braking resistors are overheating and has shut down to protect the resistors.
EF	External Fault	One of the TB-13 terminals is set as an external fault input and that terminal is open with respect to TB-11.
GF	Data Fault	User data and OEM defaults in the EPM are corrupted.
HF	High DC Bus Voltage Fault	Line voltage is too high; deceleration rate is too fast (overhauling load). For fast deceleration or overhauling loads, dynamic braking may be required.
JF	Remote Keypad Fault	The communication link between the drive and the optional remote keypad has been lost. Check for proper wiring and/or noise.
LF	Low DC Bus Voltage Fault	Line voltage is too low.
OF	Output Transistor Fault	Phase to phase or phase to ground short circuit on the output. Boost settings are too high. Acceleration rate is too fast. Failed output transistor.
PF	Current Overload Fault	VFD is undersized for the application. Mechanical problem with the driven equipment.
UF	Start Fault	Start command was present when the drive was powered up. Must wait 2 seconds after powered up to apply start command if start method is set to normal.
F1	EPM Fault	The EPM is missing or damaged.
FC	Internal Fault	The control board has sensed a problem. Replace VFD.
F2–F9	Internal Fault	The control board has sensed a problem. Replace VFD.
Fo	Internal Fault	The control board has sensed a problem. Replace VFD.

Table 3. Eaton VFD Fault Messages
Fault	Description	Possible Cause
01	Over Current	The frequency inverter has detected an excessive current in the motor cable, or there was a sudden load increase, or there was a short circuit in the motor cable, or the motor is Inadequate.
02	Over Voltage	The DC intermediate circuit voltage has exceeded the internal safety limit, or the delay time is too short, or the high over voltage peaks in line power.
03	Ground Fault	An additional leakage current was detected when starting by means of a current measurement, or there is a fault with the cable insulation or motor insulation.
08	System Fault	CPU error message or internal communication fault.
09	Under Voltage	The DC intermediate circuit voltage has exceeded the internal safety limit. Probable cause: The supply voltage is too low, or internal device fault, or site power failure.
13	Under Temperature	The IGBT switch temperature is below 14°F (-10°C)
14	Over Temperature	The IGBT switch temperature is above 248°F (120°C). An excessive temperature warning is issued if the IGBT switch temperature goes above 230°F (110°C).
15	Motor Stalled	The motor blocking protection mechanism has been triggered.
16	Motor Over Temperature	The frequency inverter’s motor temperature model has detected motor over heating. The motor is overloaded.
17	Motor Under Load	Motor idle, connection to load machine interrupted (Example: torn drive belt).
22	EEPROM Checksum Error	Error when storing parameters, or malfunction, or component fault, or error in micro-processing monitoring.
25	Watchdog (API)	Error in micro-processor monitoring, or malfunction, or component fault.
27	Back EMF	Electromotive force. The voltage induced in the motor with the rotation is greater than the output voltage of the frequency inverter.
35	Application Error	The application is not working.
41	IGBT Over Temperature	The IGBT switch temperature is above 248°F (120°C). An excessive temperature warning is issued if the IGBT switch temperature goes above 230°F (110°C).
50	Live Zero Error	Current less than 4 mA, or the voltage is less than 2V, or the signal cable was interrupted. The signal source is faulty.
51	External Fault	Error message at a digital input (DI1–DI6).
53	Fieldbus Error	The communication link between the master device and the drive's fieldbus has been interrupted.
54	Fieldbus interface error	MMX-NET-XA mounting frame for fieldbus interface cards is not connected to the frequency inverter, or the optional fieldbus interface is not fitted.