Emerson Liebert iCOM User Manual download pdf (Page 33)

Operation

23 Liebert

iCOM

Setting the counter to 0 will auto-reset the alarm without the need of pressing the reset button on the

display. Even if the pressure in the system drops below the alarm point, the compressor will remain

Off until the system is reset.

Digital Scroll High Temperature

A protective maximum operating compressor temperature limit is imposed on units with digital scroll

compressor(s) with thermistor. If the digital scroll temperature reaches the maximum temperature

threshold, the compressor will be locked out for at least 30 minutes and an alarm will be annunciated.

If after 30 minutes the temperature has cooled to a safe operating temperature, the compressor will

resume operation.

Each time a high-temperature alarm occurs, HT 1 Alarm Counter (Service Menu, Diagnostics) or

HT 2 Alarm Counter (Service Menu, Diagnostics) is increased by one. Once these counters reach five

occurrences in a rolling four-hour period, the compressor will be locked out. The alarm can be reset

once the temperature returns to a safe level by:

1. Setting the counter back to 0 from the display and pressing the alarm reset button.

2. Shutting Off power to the control board by turning the cooling unit's main power disconnect

switch Off and On.

3.1.4 Compressor Timing—Short-Cycle Protection

To help maximize the life of your compressor(s), there is a start-to-next start delay for each single

compressor.

3.1.5 Compressor Sequencing on Two-Compressor Units

Compressor Sequencing parameter (Service Menu, Options Setup) is intended to maintain equal run

times between compressors. This setting has three selection possibilities:

• Always use Compressor 1 as lead compressor.

• Always use Compressor 2 as lead compressor.

•Auto:

• First priority: if the safety timings are acceptable for only one compressor, then it is the next

to be started/stopped.

• If both compressors are Off: the one with fewer working hours is the next to start.

• If both compressors are in operation: the one that has been operating longer since the last

start is the next to be stopped.

NOTE

If the unit is equipped with manual reset high head pressure switches, or if the auto reset high

head pressure switches don’t reset, the compressor will not be turned back on, but there will be

a 30-second delay from when the high head pressure situation occurs and when the alarm is

annunciated.

NOTE

This delay may cause a short cycle if there is a very light room load. A short cycle means that

the compressor has cycled On and Off 10 times in the past hour. This is typically caused by a

lack of load or control settings set too tight (see 3.7 - Control Types for more information on

the control adjustment). Should short cycling still occur after the control has been adjusted,

contact technical support at 800-543-2778 to adjust the minimum compressor Off delay.

NOTE

The Auto setting attempts to maintain equal run times between compressors. However,

the control will not turn Off a compressor to equalize run time when it is needed to

control the space.

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 ... 191 192

Comments to this Manuals

No comments

Emerson Liebert iCOM User Manual Page 33

Comments to this Manuals