York YHAU-CW - TABLE 33 - Wet Storage Method; TABLE 34 - Dry Storage Method

JOHNSON CONTROLS
152
FORM 155.31-ICOM2.EN.UL
ISSUE DATE: 12/21/2018
SECTION 7 – MAINTENANCE
TABLE 33 - WET STORAGE METHOD
PART STORAGE METHOD NOTES
Storage Period;
less than 2 months
Chilled water line
Filled with water
1. The manual valve on the purge piping should be fully
closed (See Figure 51 on page 133).
2. The main supply valve supplying steam must be
closed.
3. If the storage period exceeds 2 months, algae and
bacteria may propagate and corrode the tubes
depending on the water quality, chemicals should be
added to avoid such propagation.
4. If the storage period exceeds 2 months, water inside
the chiller should be replaced. If the same water re-
mains in the chiller for more than 2 months, bacteria
may propagate and corrode the tubes depending
on the environmental condition and water quality.
Hence, the chilled water and cooling water pumps
should be operated for a short time and the water
inside chiller should be replaced completely (at least
once a month).
5. If the storage period exceeds 6 months, apply pres-
sure 1.5~3 PSIG with nitrogen inside the shells and
leave as it is. Internal-pressure should be checked
(at least once a week) to conrm that no pressure
drop occurs.
Cooling water line
Steam line
Vacuum
Inside of shells
Storage Period;
more than 2
months and less
than 6 months
Chilled water system
Filled with water
Cooling water system
Steam line
Pressurized with Nitrogen
(1.5~3 PSIG)
Inside of shells Vacuum
Storage Period;
more than 6
months
Chilled water system
Filled with water
Cooling water system
Steam line
Dried and pressurized with
Nitrogen (1.5~3 PSIG)
Inside of shells
Pressurized with Nitrogen
(1.5~3 PSIG)
TABLE 34 - DRY STORAGE METHOD
PART STORAGE METHOD NOTES
Storage Period;
less than 2 months
Chilled water system
Dried and pressurized with
Nitrogen (1.5~3 PSIG)
1. Chilled water and cooling water systems should be
drained completely and dried by nitrogen blow, then
pressurized with nitrogen and left as is. Depending
on the water quality, hard scale may be xed on
the inside surface of tubes by drying and it can be
removed only by chemical cleaning. For more than 1
year’s storage, it is necessary to, after cleaning the
tubes, drain completely, dry the inside by nitrogen
blow, then pressurize with nitrogen and leave as is.
2. The main supply valve supplying steam must be
closed.
3. If the storage period exceeds 6 months, apply
pressure 0.01~0.02 Mpa with nitrogen inside the
shells and leave as is. Internal-pressure should be
checked (at least once a week) to conrm no pres-
sure drop occurs.
4. The manual valve on the purge piping should be
fully closed.
Cooling water system
Steam line
Vacuum
Inside of shells
Storage Period:
more than 2
months and less
than 6 months
Chilled water system
Dried and pressurized with
Nitrogen (1.5~3 PSIG)
Cooling water system
Steam line
Inside of shells Vacuum
Storage Period;
more than 6
months
Chilled water system Dried and pressurized with
Nitrogen (1.5~3 PSIG)
Cooling water system
Steam line
Inside of shells
Pressurized with Nitrogen
(1.5~3 PSIG)