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6. The refrigerant charge can be adjusted at either refriger-
ant level. In Table 6, use the refrigerant level that corre-
sponds to the weak solution concentration in the machine
at the percent load determined in Step 4. Proceed as fol-
lows, at the appropriate refrigerant level (Fig. 23):
HIGH LEVEL — Remove temperature cutout wire from
terminal 15 .
MID LEVEL — Install jumper between terminals
15 and 41 .
TCO — Temperature Cutout
Fig. 23 — Refrigerant Levels Connection
7. Check status of Cycle-Guard™ valve. If it is open, gradu-
ally remove water from refrigerant pump service valve
until Cycle-Guard valve closes. (See Solution or Refrig-
erant Sampling section, page 34.) If Cycle-Guard valve
is closed, add small quantities of water to machine until
Cycle-Guard valve opens. Water can be drawn into the
machine through the refrigerant pump service valve when
the refrigerant pump is off. The pump can be stopped with-
out a dilution cycle by pressing the trip bar on the pump
starter overload, then depressing the Stop button and the
overload reset. Fill the charging hose with water before
opening the pump service valve. Do not allow any air to
be drawn into the machine.
Turn the refrigerant pump on after adding water. The Cycle-
Guard valve cannot be energized while the pump is off.
Add or remove water to change the solution concentra-
tion as needed. When adding or removing water, allow
approximately 10 minutes for temperatures and concen-
trations to stabilize. Periodically check weak solution con-
centration while adjusting refrigerant charge. Readjust
machine conditions, if necessary, to maintain controlled
concentration.
8. Remove jumpers from thermoswitch terminals 15 and
41 . Replace wire connections removed in Step 6.
9. If solution charge has been increased (decreased) for de-
sign conditions other than nominal, decrease (increase)
refrigerant charge by an equal amount. (Refer to Solution
and Refrigerant Charging — Charging for Conditions Other
than Nominal, page 21.)
Check Machine Shutdown —
ton momentarily. The capacity control valve closes and the
Cycle-Guard valve opens to dilute the solution. When the
solution has been sufficiently diluted, a refrigerant level switch
shuts down the machine.
Depending on solution concentration before shutdown, the
shutdown can take up to 20 minutes. If machine does not
shut down correctly, check operation of capacity controls,
refrigerant level switches, Cycle-Guard valve, and machine
wiring.
Depress the Stop but-
27
Check Low-Evaporator Level Operation —
ter machine has completed a normal shutdown:
1. Depress the Start button to start the machine. Place the
capacity control AUTO.-MAN. button in MAN. and use
( ) to keep the valve closed.
2. Wait 5 minutes for the refrigerant pump to start then place
the Cycle-Guard switch in MANUAL to transfer refrig-
erant from the evaporator, lowering the refrigerant level
until it reaches the low-level switch. The refrigerant pump
should stop. If the pump becomes noisy, it might be in
cavitation from a low-level switch malfunction. Do
NOT allow the pump to remain in operation with this
condition.
3. Return the Cycle-Guard switch and capacity control but-
ton to AUTO. for normal operation. When enough refrig-
erant has been recovered from the solution to raise the
evaporation level above the low-level switch, the refrig-
erant pump restarts.
Determine Noncondensable Accumulation Rate
—
After approximately 200 hours of machine operation, the
rate of noncondensable accumulation in the purge should be
measured to be sure that the machine does not have an air
leak. If a leak is indicated, it must be corrected as soon as
possible to minimize internal corrosion damage. Refer to Main-
tenance Procedures, Noncondensable Accumulation Rate sec-
tion on page 31 for checking procedures.
OPERATING INSTRUCTIONS
Operator Duties
1. Become familiar with absorption machine and related equip-
ment before operating. See Introduction and Machine De-
scription sections, pages 3-9.
2. Start and stop machine as required.
3. Inspect equipment; make routine adjustments; maintain
machine vacuum and proper refrigerant level; exhaust purge
as required.
4. Keep log of operating conditions and recognize abnor-
mal readings.
5. Protect system against damage during shutdown.
Before Starting Machine —
1. Power is on to condensing water and chilled water pump
starters, cooling tower fan, and absorption machine con-
trol panel (chiller Stop light is on).
2. Cooling tower has proper water level.
3. Chilled and condensing water circuits are full and valves
are open.
4. Correct steam or hot water supply is available.
5. Air supply for pneumatic controls is adequate.
6. Alarm indicator lights are off.
Start Machine —
If machine has manual auxiliary start,
first energize the auxiliaries.
To re-energize the control circuit after a safety shutdown,
depress the Stop button and then the Start button.
Now follow one of the 2 procedures described below as
it applies to your machine:
• Start-Up After Limited Shutdown — If machine has been
shut down for less than 3 weeks
• Start-Up After Extended Shutdown — If machine has been
shut down for 3 weeks or more
Af-
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