Purge Manual Exhaust Procedure; Absorber Loss Determination; Noncondensable Accumulation Rate - Carrier 16JT Series Start Up & Operation Manual

Purge Manual Exhaust Procedure (Fig. 25) —
See also Machine Description section, pages 3-9, for expla-
nation of the purge operation, component identification, and
illustrations.
NOTE: The following does not apply to optional vacuum
pump operation.
NEVER LEAVE the machine during purging opera-
tion. A failure to close the exhaust valve will disable the
machine, and could cause crystallization of the
solution.
OPERATE THE VALVES in the correct sequence.
NEVER LET AIR leak into the machine.
MAKE SURE that the tip of the vinyl tube is at the bot-
tom of the plastic bottle at all times.
NEVER SPILL any solution from the plastic bottle.
If spilled on personnel or the floor, follow the warning
pertaining to Handling Lithium Bromide Solution,
page 21.
1. Exhaust purge only when machine and solution pump are
operating, because the exhaust pressure is supplied by the
solution pump.
2. Keep end of plastic tube below the liquid level in plastic
bottle.
3. Close the solution return valve.
4. Wait approximately 5 minutes for storage chamber pres-
sure to rise above atmospheric.
5. Slowly open the exhaust valve. If the liquid level in the
exhaust bottle drops, close valve and wait approximately
2 minutes.
6. Slowly reopen the exhaust valve. If bubbles appear in the
exhaust bottle, leave exhaust valve open until bubbles stop
and solution level in bottle begins to rise. Close valve;
purge is now exhausted.
7. Open the solution return valve to resume purge
operation.
8. Slowly open the exhaust valve and allow solution in the
bottle to be drawn into the purge tube. Lower the solution
level until bottle is one-third to one-half full. Close ex-
haust valve before solution level in bottle nears the tube
end. Do not allow air to be drawn into the purge tube.
9. Log the date and time of purge evacuation to provide an
indication of changes in the rate of noncondensable
accumulation.
Absorber Loss Determination —
loss readings when machine is operating with stable
temperatures.
1. Make sure that Cycle-Guard™ valve is closed and
has not operated for at least 10 minutes before taking
readings.
2. Fill thermometer wells on discharge lines of solution and
refrigerant pumps with oil or heat conductive compound
and insert thermometers.
3. Take refrigerant and solution samples (see Solution or Re-
frigerant Sampling, page 34), and determine the specific
gravity and temperature of each sample. The samples can
be returned to the machine through the purge exhaust bottle.
4. Using the equilibrium diagram (Fig. 22A or 22B), plot
the intersection point of the specific gravity and tem-
perature of the solution sample. Extend this point
horizontally to the right and read the saturation tempera-
ture. Repeat with refrigerant sample, using Fig. 26A or
26B and reading to the left for saturation temperature.
5. Subtract the solution saturation temperature from the re-
frigerant saturation temperature. The difference is the ab-
sorber loss. Repeat the readings with a second sample to
verify steady state conditions. (On larger chillers with mul-
tiple solution pumps, determine saturation temperature for
each pump.) If the absorber loss is greater than 5° F
(3° C), machine evacuation is necessary because exces-
sive noncondensables may interfere with normal opera-
tion before they can be removed by the purge (see Ma-
chine Evacuation section, page 33).
For probable causes and suggested remedies for high ab-
sorber loss, refer to the Troubleshooting Guide, pages 41 and
42.
Noncondensable Accumulation Rate —
important maintenance item on the absorption machine is
the maintenance of machine vacuum within acceptable lim-
its. Machine vacuum tightness can be checked by determin-
ing the rate at which noncondensables accumulate. Some
noncondensables are normally generated within the ma-
chine; but an air leak or the need for additional inhibitor is
indicated if the accumulation rate increases.
Take absorber
After machine evacuation or other service, operate ma-
chine for at least 200 hours before determining noncondens-
able accumulation rate. Then proceed as follows (Fig. 27):
1. Fill a length of flexible tubing with water and connect to
the purge exhaust connection. Insert free end into a con-
tainer of water. Exhaust purge completely (see Purge Manual
Exhaust Procedure section, on this page).
2. Operate machine for 24 hours with purge operating
normally.
3. Fill a 2-pint (1000 cm
a clean container filled with water.
4. Insert the free end of water-filled hose into the bottle.
5. Follow the purge exhaust procedure. Noncondensables dis-
place water in the inverted bottle. Continue until bub-
bling in the bottle ceases and only solution flows from
exhaust tubing.
31
Fig. 25 — Purge Exhaust Assembly
3
) bottle with water and invert it in
The most