Vilter VSM 71-701, Руководство по эксплуатации и обслуживанию

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58
Service
0.00 GENERAL COMMENTS
When working on the compressor, care must be
taken to ensure that contaminants (i.e. water from
melting ice, dirt and dust) do not enter the com-
pressor while it is being serviced. It is essential
that all dust, oil or ice that has accumulated on
the outside of the compressor be removed before
servicing the compressor.
When servicing the compressor, all gaskets, O-
rings, roll pins and lock washers must be replaced
when reassembling the compressor.
It is important that if the refrigerant requires the
use of a Polyolester (POE) refrigeration oil, that
all oil is removed from the compressor unit after
the unit has been opened to the atmosphere for
servicing. POE refrigeration oils are highly
hydroscopic and will absorb large quantities of
moisture in a short time, when exposed to the
atmosphere during servicing. Once the moisture
is absorbed into the oil it is nearly impossible to
remove the moisture from the oil.
0.01 PREPARATION OF UNIT FOR
SERVICING
A) On Cool Compression units, while the unit is
running, close the main liquid ammonia line
(located before the thermostatic expansion
valve) and wait for the unit to stop by itself.
This operation will remove all the liquid am-
monia from the separator. The compressor
will stop when the superheat at discharge
reaches 25°F.
B) Shut down the unit, open the electrical dis-
connect switch and pull the fuses for the com-
pressor motor to prevent the unit from start-
ing. Put a lock on the disconnect switch and
tag the switch to indicate that maintenance
is being performed.
C) Isolate the unit by manually closing the dis-
charge Stop/Check valve. If the unit is
equipped with a V-PLUS
®
or liquid injection
cooling system, close the liquid supply valves
and open all solenoid valves to prevent liq-
uid refrigerant from being trapped between
the stop valves and solenoid valves. Allow
the unit to equalize to suction pressure be-
fore closing the Suction Bypass or Stop/
Check valve. After the unit has equalized to
suction pressure and suction valve closed,
use an acceptable means to depressurize the
unit that complies with all Local, State and
Federal Ordinances.
D) Remove drain plugs from the bottom
ofcompressor housing and the discharge
manifold On units equipped with Suction Oil
Injection (SOI) manually open the SOI sole-
noid valve below the compressor. Drain the
oil into appropriate containers.
0.02 REMOVAL OF COMPRESSOR
FROM THE UNIT
After Preparing the unit for service the following
steps should be followed when removing the com-
pressor from the unit:
A) Disconnect the motor drive coupling from the
compressor input shaft.
B) Disconnect all gas and oil piping which is
attached to the compressor. When removing
the suction strainer on VSS/VSM units or the
suction line from VSR units, the suction line
should be supported to prevent it from sag-
ging.
C) Replace oil drain in compressor housing and
discharge manifold after oil has stopped
draining.
All Oil must be removed from unit.
D) Remove all electrical connections to the com-
pressor.