Electrical Controls; Control Panel; Diagram Of The Unit's Electrical System - Carrier CU-O Series Use & Maintenance Instructions

7. PLACING INTO SERVICE OF THE UNIT

7.1 Electrical controls

8. HOW TO OPERATE THE UNIT
8.1 Description of the unit
working cycle
8.2 Diagram of the unit's
electrical system
Carrier
T
o start the machine up proceed as follows:
A) Adjust the ambient thermostat, which is on the evaporator, to the desired tempera-
ture inside the refrigerating cell. Units with remote control panels are equipped with
an electronic room thermostat which is located on the remote control panel itself.
The thermostat can be connected following the scheme; or it can work on the sole-
noid valve which pipes the refrigerant to the evaporator.
B) Position the switch preheating/stop/running, arranged by the customer, on
preheating (the indication for the connection is in the electric scheme).
C) Move the mains switch to position (ON). Leave the unit in the pre-start position
for at least 4 hours. If the temperature is particularly cold, keep the unit in the
pre-start position for at least 12 hours.
D) At the end of the pre-start phase, move the pre-start/stop/start switch to opera-
ting position.
E) If the compressor fails to start, check:
- connection to the power supply
- a blockage in the minimum pressure switch due to the lack of refrigera-
ting gas. In this case the leak must be identified and repaired before
refilling the compressor and proceeding again with the operations
illustrated above.
- Faulty auxiliary fuse = identify and eliminate the cause.

7.1.1 Control panel

The CU-O units use only one model of control panel. (fig.9)
fig.9
Uniblock CU refrigerating units operate through a sealed or semi-sealed refrige-
rating compressor, powered by mains a/c supply (three phase) and use HFC
refrigerating liquids.
Units in the CU-O range feature a special electrical system, a diagram
of which is attached to this manual.
I ON
I ON
Mains
switch
GB
D
F
I
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