Start−Up; First Start−Up (Or After Long Standstill); Starting And Stopping; Automatic Restart - Liebert himod Service Manual

6 − Start−up
First start−up (or after long stand-
6.1 −
still)
Start the air conditioner as follows:
1) Open all valves in the water circuit according to the
instruction label attached to the valve.
2) Check that there are no water leakages.
3) Bleed all air out of the chilled water circuit using
the bleed valve on the chilled water coil.
4) Close all MCBs on the electrical panel.
5) Check the supply voltage on all phases.
6) Start the unit by pressing ON OFF (see Fig. 13).
7) Check the electrical absorption of all components
(see Chap. 5).
8) Ensure that the fans rotate in the correct direction
(see arrow on fan).
CAUTION: risk of contact with rotating devices.
9) Ensure that all control system settings are correct
and that there are no alarms (see Control manual).
10)Verify the water flow.
11)Verify the Fresh Air Intake operation (if fitted).
12)Once the system is operating under load, check the
various components, as follows:
S Verify that the fans are operating properly.
S Ensure that the temperature and relative hu-
midity are being controlled, and that the humid-
ifier (optional) and heating steps (optional) op-
erate when required.
S Ensure that chilled water valve operates when
required.
7 − Operation
Unit operation is completely automatic. The below se-
quence explains how the unit operates :
S The air, sucked in by the fan(s), enters the unit.
S The air is immediately filtered.
S The TEMPERATURE sensor or HUMITEMP (tem-
perature + rel. humidity) sensor
installed), verifies the state of the inlet air, and relays
this information to the control system.
S The control system compares the relayed informa-
tion to the set point and proportional band values
programmed into its memory: it then commands the
air conditioner to treat the air as follows (see also
Control manual):
S COOLING
Chilled water flows through the chilled water
coil, thus cooling the air passing over it. The
chilled water flow is controlled by a timed mod-
ulating (3−way) valve, which regulates the flow
rate in order to obtain the exact amount of cool-
ing required.
S HEATING
This can take one of two forms:
24
6.2 −
Turn on the unit operating on the ON/OFF switch pla-
ced on the left case of the unit (Fig. 13). If the ON/OFF
remote device is not installed, the green LED on the
Microface case will light up together with the LED pla-
ced below the ON/OFF switch. The fan starts imme-
diately (the fan always works when the unit is ON); af-
ter 2 minutes the regulation is activated, so the cooling
(compressor), heating (electric heaters), humidifying
and dehumidifying devices can start.
Adjust the set−point as indicated in
.
nual
Stop the unit putting the ON/OFF switch in OFF.
S The main switch QS should only be switched off if
the unit is stopped for a long period of time.
6.3 −
If desired, the unit will automatically restart on the re-
turn of power after a supply interruption (see Control
manual).
Fig. 13 − On−Off switch
− electrical heating (optional): the heating ele-
− hot water heating (optional): if hot water is
(check type
S DEHUMIDIFICATION − optional
S HUMIDIFICATION − optional
HIMOD−C

Starting and stopping

Automatic restart

ments heat the air passing over them. There are
3 heating steps.
available, this flows through the hot water coil,
thus heating the air passing over it. The hot wa-
ter flow is controlled by an on−off (3−way)
valve.
Maximum chilled water flow is requested
through the coil, whose temperature drops be-
low the dew point of the air, thus dehumidifying
it.
If necessary, heating is used to reheat the air.
N.B.: If, during dehumidification, the ambient
temperature drops below a specified level, de-
humidification will be stopped if necessary (see
LOW LIMIT intervention in Control manual).
The humidifier creates steam, which is distrib-
uted into the air stream via the steam distribu-
tion pipe (see also App. A).
Control ma-
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