Troubleshooting
8.0TROUBLESHOOTING
Use this section to assist in troubleshooting your unit. Also refer to 6.0 - Alarm Descriptions. Sug- gestions are grouped by product function for convenience.
! WARNING
Risk of electric shock. Can cause injury or death.
The Liebert iCOM microprocessor does not isolate power from the unit, even in the “Unit Off” mode. Some internal components require and receive power even during the “Unit Off” mode of Liebert iCOM control.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote disconnect switch. Refer to unit electrical schematic.
Only properly trained and qualified personnel should service these units. Lethal voltage is present in some circuits. Use caution when troubleshooting with power On. Disconnect and lock out power before replacing components.
! WARNING
Risk of explosive discharge from
This unit contains fluids and gases under high pressure. Relieve pressure before working with piping.
NOTICE
Risk of improper control connection. Can cause equipment damage.
When using jumpers for troubleshooting, always remove jumpers when maintenance is complete. Jumpers left connected could override controls and cause equipment damage.
Table 12 Blower troubleshooting
Symptom | Possible Cause | Check or Remedy |
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| No main power | Check L1, L2 and L3 for rated voltage. |
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| Blown fuse or tripped circuit breaker (CB) | Check fuses or CBs to main fan. |
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Blower will not | Overloads tripped | Push reset button on main fan overload. Check amp draw. |
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start | No output voltage from transformer | Check for 24 VAC between |
| voltage, check primary voltage. | |
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| Control fuse blown or circuit breaker tripped | Check for 24 VAC between |
| check for short. Replace fuse or reset circuit breaker. | |
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Table 13 Chilled water troubleshooting
Symptom | Possible Cause | Check or Remedy | |
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Chilled water or hot | Motor operates but valve |
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water/steam valve | Check linkage for adjustment and be sure that it is tight on the valve. | ||
won’t open | |||
not opening |
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| No 24 VAC power to motor | Check linkage for adjustment and be sure that it is tight on the valve. | |
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| Check DC voltage on printed circuit board in motor. Terminal No. 1 is | |
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| grounded and No. 3 is positive. DC voltage should vary from 0.8 to | |
| No signal from control | 2.0 VDC or above as temperature control is varied below room | |
Modulating Motors |
| temperature on cooling valve or above room temperature on heating | |
| valve. | ||
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| ||
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| Remove wires on Terminal No. 1 and No. 3 from the motor (do not | |
| Motor not working | short). With 24 VAC power from TR to TR jumper terminal 1 and 2 on | |
| motor to drive open. Remove jumper to drive closed, if motor fails to | ||
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| ||
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| work, replace it. | |
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Actuator Motors | No 24 VAC power to motor | Check for 24 VAC between | |
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