Emerson 3000/ITR Manuale Utente

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.

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.

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.

Risk of explosive discharge from high-pressure refrigerant. Can cause injury or death.
This unit contains fluids and gases under high pressure. Relieve pressure before working with 

piping.

Blower will not 

start

No main power

Check L1, L2 and L3 for rated voltage.

Blown fuse or tripped circuit breaker (CB)

Check fuses or CBs to main fan.

Overloads tripped

Push reset button on main fan overload. Check amp draw.

No output voltage from transformer

Check for 24 VAC between P24-2 and P24-1. If no 

voltage, check primary voltage.

Control fuse blown or circuit breaker tripped

Check for 24 VAC between P4-4 and E1. If no voltage, 

check for short. Replace fuse or reset circuit breaker.

Chilled water or hot 

water/steam valve 

not opening

Motor operates but valve 

won’t open

Check linkage for adjustment and be sure that it is tight on the valve.

Modulating Motors

No 24 VAC power to motor

Check linkage for adjustment and be sure that it is tight on the valve.

No signal from control

Check DC voltage on printed circuit board in motor. Terminal No. 1 is 

grounded and No. 3 is positive. DC voltage should vary from 0.8 to 

2.0 VDC or above as temperature control is varied below room 

temperature on cooling valve or above room temperature on heating 

valve.

Motor not working

Remove wires on Terminal No. 1 and No. 3 from the motor (do not 

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 

work, replace it.

Actuator Motors

No 24 VAC power to motor

Check for 24 VAC between P22-3 and P22-5 (open), or P22-1 and 

P22-5 (closed).