16
Always
start with a fresh oil charge in
the vacuum pump.
Always
use a liquid trap or collection
flask.
Always
use a vacuum gauge to verify
the level of vacuum achieved. Run
time has almost nothing to do with the
level of vacuum achieved.
Never
pull a vacuum if the ACT5
Maintenance Checker indicates an LT
temperature exceeding 90°F
(32°C)
.
Never
pull an extended vacuum
(exceeding a few hours)
. If such seems
to be necessary, there is likely to be
something wrong with the vacuum
pump
or
the
oil
has
been
contaminated with moisture inherently
found inside the chiller-heater vacuum
section.
Use only dual-stage, deep vacuum
pumps. Typical refrigeration vacuum
pumps may not perform well on a vessel
as large as the chiller-heater vacuum
section. Just because the vacuum pump
has stopped producing bubbles in the
water bucket does NOT mean the
vacuum level is adequate. A digital
vacuum gauge MUST be used in order to
determine the true level of vacuum
achieved.
The desired level of vacuum on a
machine that is not running would be
less than 2000 microns
(<2mmHg)
, with
less
than
1000
microns
(<1mmHg)
preferred. On a machine actively
running in Cool mode
(burner engaged)
,
the desired level of vacuum is 5000
microns
(5mmHg),
no less. Any lower
than 5000 microns
(5mmHg)
on a running
machine will cause the vacuum pump to
remove an extraordinary amount of
refrigerant vapor
(water)
.
A step-by-step, detailed evacuation
method is provided in Section 5 of the
Service Manual. The general evacuation
assembly setup is displayed in Fig. 11.
Fig. 11
– General Evacuation Assembly Setup
