Table of Contents
Advertisement
SHORT INTERVAL TEST — Use this test procedure if:
1. No previous absolute pressure readings have been re-
corded, OR
2. Previous absolute pressure reading was made less than 4
weeks ago, or reading indicated a machine pressure of
more than 1 in. (25 mm) of mercury, OR
3. Machine had to be leak tested after long interval test.
Procedure
1. Connect absolute pressure gage to auxiliary evacuation
valve and record pressure reading.
2. If the reading is more than 1 in. (25 mm) of mercury ab-
solute, evacuate the machine as described in the Main-
tenance Procedures section, page 33.
3. Record the absolute pressure reading and the ambient
temperature.
4. Let machine stand for at least 24 hours.
5. Note the absolute pressure reading when ambient tem-
perature is within 15° F (8° C) of the ambient tempera-
ture recorded in Step 3.
6. If there is any noticeable increase in pressure, an air leak
is indicated. Leak test the machine as described in Main-
tenance Procedures section, then repeat short interval vacuum
test to ensure results.
Machine Evacuation —
sure is greater than 1 in. (25 mm) of mercury absolute, ma-
chine must be evacuated as described in Maintenance Pro-
cedures section, page 33.
Solution and Refrigerant Charging
HANDLING LITHIUM BROMIDE SOLUTION
Lithium bromide and its lithium chromate inhibitor can
irritate the skin and eyes. Wash off any solution with
soap and water. If solution enters the eye, wash the eye
with fresh water and consult a physician immediately.
Lithium bromide is a strong salt solution; do not syphon
by mouth.
Liquid materials that are added to lithium bromide
solution such as lithium hydroxide, hydrobromic acid,
octyl alcohol, and lithium chromate inhibitor, are clas-
sified as hazardous materials. These materials, and any
lithium bromide solution they are in, must be handled in
accordance with current Occupational Safety and Health
Administration (OSHA) and Environmental Protection
Agency (EPA) regulations.
Solutions of lithium bromide and water are nontoxic, non-
flammable, nonexplosive, and can easily be handled in open
containers. The solution is chemically stable and does not
undergo any appreciable change in properties even after years
of use in the absorption machine. Its general chemical prop-
erties are similar to those of table salt.
Because lithium bromide salt can corrode metal in the pres-
ence of air, wipe off any solution spilled on metal parts or
tools and rinse the part with fresh water as soon as possible.
After rinsing, coat the tools wih a light film of oil to prevent
rust. After emptying metal containers of solution, rinse the
container with fresh water to prevent corrosion. Immedi-
ately wipe or flush the floor if lithium bromide or octyl al-
cohol is spilled on it.
Lithium bromide should be stored only in the original con-
tainer or in a completely clean container. Used lithium bro-
mide solution should be disposed of by a reputable chemical
disposal company.
CHARGING SOLUTION — Solution is drawn into the ab-
sorber through the solution pump service valve while the
When machine absolute pres-
pump is off. To minimize the chance of air entering the ma-
chine, the solution should not be drawn in directly from a
small container. A vacuum pump should be in operation while
the solution is being charged into the chiller to remove en-
trained noncondensables.
1. Connect a flexible hose to a
⁄
-in. (15-mm) pipe. Fill both pipe and hose with water
1
2
to minimize any air entry into the machine.
2. Insert the
1
⁄
-in. (15-mm) pipe into the container (be sure
2
it goes to the bottom), and connect the flexible hose to
the solution pump service valve (Fig. 20). The lithium
bromide container must have yellow, ''Lithium Chro-
mate Inhibitor'' markings, and a 55% concentration so-
lution must be used.
3. Open the service valve. Continue charging until solution
level is near the bottom of the container. Do not allow air
to be drawn into machine.
4. Repeat with other containers as required until the amount
specified in Table 3 has been charged into the chiller.
Fig. 20 — Charging Solution and Refrigerant
CHARGING FOR CONDITIONS OTHER THAN NOMI-
NAL — The solution quantity can be adjusted to compen-
sate for other than nominal values for design chilled water
temperature, condensing water temperature or flow. The so-
lution quantity can be increased or decreased by up to 10%
of the nominal charge listed in Table 3. Adjust quantity as
follows:
1. Increase (decrease) the nominal solution charge by 1%
for each degree F (.56° C) that the design chilled water
temperature is below (above) 44 F (7 C).
2. Increase (decrease) the nominal solution charge by 1%
for each 2° F (1.1° C) that the design condensing water
temperature is above (below) 85 F (29 C).
3. Increase the nominal solution charge by 1% for each 10%
reduction in design condensing water flow below nomi-
nal 100%.
4. Do not adjust nominal charge for changes in steam
pressure.
INITIAL REFRIGERANT CHARGING — The refrigerant
charge must be either distilled or deionized water. Do not
use tap water without first having it tested for the following
requirements:
pH
Hardness CaCO
3
Silica
Ammonia NH4+
Specific Resistance
21
1
⁄
-in. MPT adapter and a
2
7.0 ± 0.2 at 77 F (25 C)
2.0 ppm or less
0.2 ppm or less
None
5
5 x 10
ohms/cm
at 77 F (25 C)
Hide quick links:
Advertisement
Table of Contents
