ROUTINE MAINTENANCE
Routine
maintenance
should
be
provided throughout the life of the
equipment in order to ensure satisfactory
operation and performance.
During the warranty period, an ASP
must be engaged to provide routine
maintenance at the beginning of each
cooling season
(spring changeover)
and
heating season
(fall changeover)
. When
the chiller-heater is used for process
cooling or heavy load operation, it may
be necessary to schedule additional
service
visits
to
evacuate
non-
condensable gasses from the vacuum
section.
Be aware that during the first few
months of operation, non-condensable
gases may accumulate at a greater rate
than expected as the inhibitor coating in
the unit finishes forming. However, after
approximately 3 months, the formation of
non-condensable gases should decrease
to the normal expected rates.
Each routine maintenance item is
covered in detail, many in step-by-step
detail, in Section 5 of the Service
Manual. What is provided here is a brief
summary of what the Service Manual
covers.
EVACUATION OVERVIEW
Arguably the most important aspect of
maintenance for the chiller-heater is
maintaining a proper level of vacuum.
Evacuation is performed at the front of
the machine. The evacuation service
valves are referred to as Service Valve A
(upper)
and Service Valve B
(lower)
.
Refer to Fig. 4 for detail on where these
valves are located at the front of the unit.
The evacuation service valves are
back-seating access valves similar to
those used throughout the refrigeration
industry. The stem has a 10mm square
head. The stem secures a copper seal
to a steel seat inside the valve. Do not
over-torque this valve or else the seal
can become damaged and compromise
vacuum integrity.
Yazaki offers a torque wrench
(P/N
N7510)
specifically for use with this service
valve.
A number of precautions should be
observed at all times during evacuation.
Key points are:
*** Great care must be taken to
ensure that no oil enters the Yazaki
chiller-heater! Permanent damage
could result from even a small amount
of oil being introduced into the
vacuum section! ***
Never
leave a vacuum pump running
unattended. Power loss could allow
the chiller-heater vacuum section to
suck oil out of the pump in a matter of
minutes.
Never
have the Service Valve open
unless the vacuum pump is running
and the integrity of the vacuum lines
between the valve and the pump has
been verified as tight.
Never
have
the vacuum
pump
discharge tube in the water bucket
unless the vacuum pump is running.
The vacuum pump could suck water
from the bucket and contaminate the
oil charge.
Never
pull a vacuum when the unit is
running in Heat mode. Only pull a
vacuum in
“Off” or “Cool” modes.
