York YCAJ44HE8, Installation, Operation And Maintenance Manual

Page: 72 / 92

72 YORK INTERNATIONAL
It is the responsibility of the owner to provide the neces-
sary daily, monthly and yearly maintenance require-
ments of the system.
IMPORTANT
If a system failure occurs due to improper main-
tenance during the warranty period; YORK will
not be liable for costs incurred to return the sys-
tem to satisfactory operation. The following is
intended only as a guide and covers only the
chiller unit components. It does not cover other
related system components which may or may
not be furnished by YORK. System compo-
nents should be maintained according to the in-
dividual manufacturers’ recommendations as
their operation will affect the operation and life of
the chiller.
DAILY MAINTENANCE
It is recommended that the following items be checked
daily.
1. Oil Level – Correct oil level is when oil appears in
either of the compressor oil sight glasses after the
unit necessary to add oil after this operating period,
see item #3 under the ANNUAL MAINTENANCE
section.
8. After 90 seconds of run time, if cooling demand
requires and no safeties have been exceeded the lag
compressor will start unloaded. Coincident with the
start, the programmable anti-recycle counter will be
set and begin counting downward to “0”. The liquid
line solenoid will open when the system is pumped
down to the suction pressure cut-out.
9. After 94 seconds of run time, the oil pressure of
the lag compressor must be a minimum of 5 PSID
and suction pressure must be greater than 50% of
cut-out.
10. After 2 minutes of run time, the lead compressor
will continue to load, if cooling demand (temperature
and rate control) requires and extra steps of capac-
ity are present. The oil pressure of the lag compres-
sor must be a minimum of 20 PSID and the suction
pressure must be a minimum of 50% cut-out.
11. After 2 minutes and 30 seconds of run time, the
lag compressor will load, if cooling demand (tem-
perature and rate control) requires.
12. After 3 minutes of run time, the lead compressor
will load, if cooling demand (temperature and rate
control) requires, and extra steps of capacity are
present.
13. After 3 minutes and 30 seconds of run time, the
lag compressor will load, if optional stages of loading
are present and cooling demand requires.
14. After 4 minutes or runtime, the lead compressor’s
suction pressure must be greater than the pro-
grammed cut-out. In addition, the oil pressure of the
lead compressor must be greater than 25 PSID.
15. After 4 minutes and 30 seconds of run time, the
lag compressor will load, if optional stages of loading
are present and cooling demand requires.
16. After 5 minutes and 30 seconds of run time, the
lag compressor’s suction pressure must be greater
than the programmed cut-out. In addition, the oil
pressure of the lead compressor must be greater
than 25 PSID.
17. Operation beyond 6 minutes will be dictated by cool-
ing demand. Anti-recycle timers will time out and
system safety thresholds will confine to be moni-
tored.
PREVENTATIVE MAINTENANCE
2. Oil Pressure – Oil pressure should be a minimum
of 50 PSI above suction pressure. Typical pressure
is 65 - 70 PSI.
3. Compressor Superheat – Correct superheat is
10 - 15°F measured at the compressor.
4. Operating Pressures and Temperatures – Check
to see that operating pressures and temperatures are
within the LIMITATIONS shown in this book.
WEEKLY MAINTENANCE
It is recommended that the following items be checked
weekly.
1. All items listed under DAILY MAINTENANCE.
2. Color of Compressor Oil – New oil is clear, and if
the system is not contaminated with moisture and/
or foreign material, it should retain its new appear-
ance for a reasonable length of operating time.
Discoloration of the oil, either turning darker brown or
in some cases lighter, is an indication of contamina-
tion, basically due to moisture. If it is necessary to
charge oil refer to item #3 under the ANNUAL MAIN-
TENANCE section.
3. Check the refrigerant circuit for leaks.